1) The document discusses different types of photobioreactors used to cultivate phototrophic microorganisms like microalgae.
2) Open pond systems are simpler but have disadvantages like lower productivity due to light limitations, CO2 and water losses, and higher contamination risks. Closed photobioreactors allow better control of parameters.
3) Recent trends in closed photobioreactor design include tubular and plate configurations to increase surface area exposed to light, as well as very thin culture layers to improve light distribution, leading to higher biomass concentrations and productivities.
Eze Chinwe Catherine presented on applying nanotechnology to microbial pollution control. Key points:
1) Nanotechnology involves manipulating matter at the atomic scale between 1-100 nanometers. Properties change dramatically at this scale, enabling novel applications like selective sensors, fast dissolution, and catalytic/antimicrobial activity.
2) Nanomaterials like carbon nanotubes, nanoparticles, and dendrimers have antimicrobial properties that can physically pierce cells and inhibit biofilm formation on surfaces. Silver nanoparticles generate ions that bind to microbes and inactivate them.
3) Nanotechnology enables more targeted and effective bioremediation through enzyme immobilization techniques like single enzyme nanoparticles, which allow enzymes to withstand extreme conditions while maintaining
The document summarizes the state of wastewater treatment technologies. It discusses best available technologies (BAT) as those proven effective and efficient. The core BATs are intensive and extensive biological treatment technologies. Intensive technologies use suspended biomass in activated sludge or attached biomass in trickling filters. Extensive technologies include constructed wetlands, lagoons, and biological lakes. Driving forces for development include legislation, climate change, water scarcity, and energy efficiency goals. While wastewater has some energy potential, it represents a small fraction of typical plant or household energy usage.
The document discusses the use of nanobioremediation to clean up environmental pollution. It proposes using genetic engineering and nanoparticles to enhance the ability of microorganisms to remediate contaminants. Key points:
1) Nanoparticles and genetic engineering can be used to modify microbial cells to increase their ability to degrade various pollutants like heavy metals and organic compounds through increased enzyme production and substrate specificity.
2) Immobilizing microbial cells and enzymes onto nanoparticles increases their stability and reusability, improving bioremediation efficiency.
3) A radioresistant bacterium, Deinococcus radiodurans, has been genetically engineered to remediate multiple contaminants found in radioactive waste, providing a
This document summarizes a seminar report on photobioreactors. It defines a photobioreactor as a bioreactor that uses light to cultivate phototrophic microorganisms like algae and cyanobacteria. It then describes some common types of photobioreactors including open systems like raceway ponds and circular ponds, and closed systems like tubular, flat plate, and internally illuminated reactors. The document lists factors that affect photobioreactor performance and criteria for selecting different photobioreactor designs. It concludes that the type of photobioreactor and operating factors influence microalgae growth and downstream product yields.
This document discusses the production of algae using photobioreactors. It reviews different types of photobioreactors including open systems like raceway ponds and closed systems. Closed photobioreactors have advantages over open systems like better environmental control and prevention of contamination. The document describes various closed photobioreactor designs - vertical tubular, flat panel, horizontal tubular, bubble column, airlift, helical, and stirred tank. It notes that hybrid designs that combine features may be most suitable for mass algae cultivation.
Nano technology for crop resilience to climate change,
this seminar mainly related to crop response to applied nano particles in different environmental stresses like drought ,salt stress,etc,.
This document discusses the topic of nanobioremediation. It begins with introductions to nanoscience and bioremediation. Nanobioremediation uses nanoscience and nanoparticles to enhance microbial activity and remove pollutants more quickly. Examples are given of using genetic engineering and nanoparticles to modify microbes for improved bioremediation. The document concludes that nanobioremediation can clean environmental hazards faster and safer than other methods while meeting economic, social, and environmental criteria.
Biotechnology can be applied to waste management through microbial fuel cells (MFCs). MFCs use microorganisms to convert the chemical energy in organic compounds into electrical energy. They have two chambers, an anode where microbes in the wastewater oxidize organic matter and release electrons and protons, and a cathode where oxygen reacts with the electrons and protons to form water. This generates a current that can be used as energy. The document describes a student's experiment using an MFC with effluent water, which generated voltages of up to 120mV over 5 days. MFCs provide a way to both treat wastewater and produce renewable energy, though further improvements are still needed.
Eze Chinwe Catherine presented on applying nanotechnology to microbial pollution control. Key points:
1) Nanotechnology involves manipulating matter at the atomic scale between 1-100 nanometers. Properties change dramatically at this scale, enabling novel applications like selective sensors, fast dissolution, and catalytic/antimicrobial activity.
2) Nanomaterials like carbon nanotubes, nanoparticles, and dendrimers have antimicrobial properties that can physically pierce cells and inhibit biofilm formation on surfaces. Silver nanoparticles generate ions that bind to microbes and inactivate them.
3) Nanotechnology enables more targeted and effective bioremediation through enzyme immobilization techniques like single enzyme nanoparticles, which allow enzymes to withstand extreme conditions while maintaining
The document summarizes the state of wastewater treatment technologies. It discusses best available technologies (BAT) as those proven effective and efficient. The core BATs are intensive and extensive biological treatment technologies. Intensive technologies use suspended biomass in activated sludge or attached biomass in trickling filters. Extensive technologies include constructed wetlands, lagoons, and biological lakes. Driving forces for development include legislation, climate change, water scarcity, and energy efficiency goals. While wastewater has some energy potential, it represents a small fraction of typical plant or household energy usage.
The document discusses the use of nanobioremediation to clean up environmental pollution. It proposes using genetic engineering and nanoparticles to enhance the ability of microorganisms to remediate contaminants. Key points:
1) Nanoparticles and genetic engineering can be used to modify microbial cells to increase their ability to degrade various pollutants like heavy metals and organic compounds through increased enzyme production and substrate specificity.
2) Immobilizing microbial cells and enzymes onto nanoparticles increases their stability and reusability, improving bioremediation efficiency.
3) A radioresistant bacterium, Deinococcus radiodurans, has been genetically engineered to remediate multiple contaminants found in radioactive waste, providing a
This document summarizes a seminar report on photobioreactors. It defines a photobioreactor as a bioreactor that uses light to cultivate phototrophic microorganisms like algae and cyanobacteria. It then describes some common types of photobioreactors including open systems like raceway ponds and circular ponds, and closed systems like tubular, flat plate, and internally illuminated reactors. The document lists factors that affect photobioreactor performance and criteria for selecting different photobioreactor designs. It concludes that the type of photobioreactor and operating factors influence microalgae growth and downstream product yields.
This document discusses the production of algae using photobioreactors. It reviews different types of photobioreactors including open systems like raceway ponds and closed systems. Closed photobioreactors have advantages over open systems like better environmental control and prevention of contamination. The document describes various closed photobioreactor designs - vertical tubular, flat panel, horizontal tubular, bubble column, airlift, helical, and stirred tank. It notes that hybrid designs that combine features may be most suitable for mass algae cultivation.
Nano technology for crop resilience to climate change,
this seminar mainly related to crop response to applied nano particles in different environmental stresses like drought ,salt stress,etc,.
This document discusses the topic of nanobioremediation. It begins with introductions to nanoscience and bioremediation. Nanobioremediation uses nanoscience and nanoparticles to enhance microbial activity and remove pollutants more quickly. Examples are given of using genetic engineering and nanoparticles to modify microbes for improved bioremediation. The document concludes that nanobioremediation can clean environmental hazards faster and safer than other methods while meeting economic, social, and environmental criteria.
Biotechnology can be applied to waste management through microbial fuel cells (MFCs). MFCs use microorganisms to convert the chemical energy in organic compounds into electrical energy. They have two chambers, an anode where microbes in the wastewater oxidize organic matter and release electrons and protons, and a cathode where oxygen reacts with the electrons and protons to form water. This generates a current that can be used as energy. The document describes a student's experiment using an MFC with effluent water, which generated voltages of up to 120mV over 5 days. MFCs provide a way to both treat wastewater and produce renewable energy, though further improvements are still needed.
Nanotechnology is the emerging technology in almost all fields of science ..It is preferred and studied due to its high efficiency in all fields of its application... Also being used in overcoming or eliminating environmental pollution to a greater level, this presentation is all about how Nanotechnology is useful in treating polluted water
Gonzalez, 2008, Sulfur Formation And Recovery In A Thiosulfate Oxidizing Bior...roelmeulepas
This article discusses a bioreactor system that allows for high production and recovery of elemental sulfur from thiosulfate oxidation. The system, called a Supernatant-Recycling Settler Bioreactor (SRSB), consists of an upflow bioreactor and separate aeration vessel. The bioreactor contains an internal settler and packing material to facilitate cell retention and settling of produced sulfur. Supernatant is continuously recirculated between the bioreactor and aerator. Testing achieved 98-100% thiosulfate conversion and a 77% elemental sulfur yield, with 93% of sulfur recovered from the bioreactor bottom as sludge containing 87% sulfur. The internal settler and packing
The document discusses environmental biotechnology and its applications. It provides details about (1) using microorganisms to treat hazardous wastes and pollution, including bioremediation of contaminated soil and water, (2) the treatment process at a common effluent treatment plant (CETP) that cleans waste water from textile industries, and (3) two case studies on bioremediation of oil-contaminated soil and waste water treatment at a CETP.
This document discusses concepts related to bioplastics and biodegradable plastics. It begins by defining conventional plastics and their properties, as well as bioplastics. There are two types of bioplastics - those derived from biomass and those that are biodegradable. The document then discusses standards for biodegradability and compostability, noting that current standards do not fully capture biodegradation under natural environmental conditions. It also suggests that industry groups have influenced standards and definitions in ways that overstate the sustainability and environmental friendliness of certain bioplastics. In summary, the document provides background on plastics and bioplastics, discusses standards and their limitations, and notes industry influence over definitions and standards
This document discusses nanoscience and nanotechnology applications in agriculture. It defines nanotechnology as controlling matter on an atomic and molecular scale between 1 to 100 nm. The document outlines several applications of nanotechnology in agriculture including controlled release of agrochemicals like fertilizers and pesticides, targeted delivery of biomolecules to plants, use of nanosensors to detect pathogens and monitor soil/plant growth, nanofertilizers to address nutrient deficiencies, nano-pesticides for effective pest control, nanoherbicides that target weed roots, and nanobarcodes for tracking agricultural products. The document also discusses using nanotechnology to recycle agricultural wastes and enhance biofuel production. While promising, the document notes nanotechnology raises
Nanotechnologies show potential for environmental cleanup through remediation of contaminated groundwater and soil. Specifically, injecting nanoparticles containing zero-valent iron (nZVI) underground can degrade pollutants in situ. However, the nZVI used is larger than true nanoparticles and behaves more like environmental colloids than nanoparticles. Its reactivity comes from high surface area rather than nanoscale effects, and it has limited mobility underground of only a few meters. More research is still needed to understand how nZVI transforms over time and impacts the environment.
Bioremediation - prospects for the future application of innovative appliedIvan Vera Montenegro
1) Bioremediation uses biological processes to eliminate, attenuate, or transform polluting substances. Traditional techniques like biopiling and landfarming rely on microbial degradation of contaminants in soil. Phytoremediation uses plants and their rhizospheres to uptake or degrade contaminants.
2) Phytobial remediation combines phytoremediation and bioremediation by using microbes like Trichoderma harzianum colonized in plant roots to efficiently degrade toxicants while providing an energy source from plant root exudates.
3) Initial experiments found T. harzianum could detoxify cyanides and metallocyanides in soil, allowing plant
1) Environmental biotechnology uses biological processes to study and benefit the natural environment, such as remediating pollution or developing green technologies.
2) Bioaccumulation occurs when organisms absorb substances like pesticides at a higher rate than they can eliminate them, resulting in increasing concentration of the substance in the organism's body over time.
3) Bioremediation uses microorganisms to remove pollutants from the environment, either on-site (in situ) or by removing contaminated material (ex situ). Examples include phytoremediation and bioleaching.
Characterization of Clay/Chitosan Nanocomposites and their Use for Adsorption...Editor IJCATR
The document describes a study that prepared nanocomposite films from chitosan biopolymer and montmorillonite nanoclay (MMT) at various weight percentages. XRD and FTIR were used to characterize the structural properties of the nanocomposites and showed an intercalated structure formed. The nanocomposites were then used to adsorb Mn(II) ions from aqueous solution. Parameters like pH, contact time, adsorption mass, initial concentration, and temperature were investigated. Adsorption isotherms and kinetics as well as thermodynamic properties of the process were analyzed.
Nanotechnology in waste water treatmentSakthivel R
This document discusses how nanotechnology can be used for waste water treatment. It explains that nanoparticles are effective at removing pollutants from water due to their high surface area. Various nanomaterials like metal nanoparticles, carbon nanomaterials, and zeolites can be used. Specifically, nano sorbents can sorbe a wide variety of organic and inorganic contaminants, nano catalysts can increase reaction rates to degrade contaminants, and biomimetic membranes allow for efficient desalination using reverse osmosis. Molecularly imprinted polymers also selectively remove pollutants even at low concentrations. Overall, nanotechnology provides effective, efficient, and eco-friendly approaches to water treatment.
This document discusses the development of a slow-release nitrogen fertilizer using hydroxyapatite nanoparticles modified with urea. Bench-scale testing showed the nanofertilizer provided slow release of nitrogen and improved phosphorus availability compared to granular urea alone. Field tests on rice crops demonstrated higher yields with the nanofertilizer when applied at 50% of the normal urea dosage. Use of such a nanofertilizer could help reduce urea losses estimated at 70% of usage in Sri Lanka, saving an estimated $44 million annually while minimizing environmental impacts.
1. Nanotechnology shows potential for improving water treatment through the use of nanomaterials for filtration, remediation, sensing, and disinfection. Various nanomaterials under research include carbon nanotubes, nanoparticles, and dendrimers for filtration and zeolites, carbon nanotubes, and nanoparticles for remediation.
2. While nanotechnology could address issues like water scarcity and quality, research is still needed to fully understand the toxicity of engineered nanoparticles. More data is needed on their environmental and health impacts before large-scale use in water applications.
3. Overall, nanotechnology represents an emerging area that may lead to novel solutions for water treatment through the unique properties of nanomaterials. However, more
This document discusses bioremediation, which uses microorganisms to return environments contaminated by pollutants to their original condition. It describes two types of bioremediation: in situ, which treats contamination on site, and ex situ, which treats contamination off site. In situ bioremediation can be intrinsic, occurring naturally over time, or engineered through additions to stimulate microbes. Ex situ involves removing contaminated waste and treating it through solid phase methods like composting or slurry phase systems in bioreactors. Key factors that affect bioremediation include moisture, pH, temperature, nutrients, contaminant concentration, and microbial populations.
The document discusses the use of NatureVel-WW, a bioaugmentation product, for wastewater treatment. It contains mixed cultures of beneficial microbes that work synergistically to break down organic compounds and reduce BOD, COD, and pathogens. The product is applied in initial booster doses and maintenance doses to inoculate treatment systems and ensure the introduced microbes dominate over indigenous populations, improving system efficiency and reliability while reducing sludge and odors.
This document reviews the use of nanotechnology for waste water treatment. It discusses how nanoparticles have a high surface area and unique properties that allow them to efficiently remove toxins, microbes, and other contaminants from water. Various nanomaterials can be used, including metal nanoparticles, carbon nanomaterials, zeolites, and dendrimers. The document summarizes recent research on nanostructured catalytic membranes, nanosorbents, nanocatalysts, bioactive nanoparticles, biomimetic membranes, and molecularly imprinted polymers for applications in water treatment. Nanotechnology approaches provide efficient, precise, and scalable ways to treat waste water with benefits like lower costs and energy usage compared to conventional methods. However, more research is
The document discusses bioremediation of industrial wastewater using Pseudomonas aeruginosa. It provides background on the increasing volume of industrial wastewater polluting water sources and the need for effective treatment. The study aims to assess water quality parameters like BOD, COD, pH, TSS, TS and alkalinity before and after bioremediation of wastewater using P. aeruginosa over 15 days. The results will show if this microorganism can decrease waste and help treat industrial wastewater.
This document discusses bioaugmentation as a remediation technology. It introduces bioaugmentation and describes different bioaugmentation technologies including cell bioaugmentation, gene bioaugmentation, rhizosphere bioaugmentation, and phytoaugmentation. Cell bioaugmentation involves using carrier materials or encapsulation to deliver microorganisms to contaminated sites. Gene bioaugmentation uses horizontal gene transfer to introduce remediation genes. The document also provides case studies of bioaugmentation in coke plant wastewater and oilfield wastewater treatment and discusses benefits and challenges of bioaugmentation.
BIOTECHNOLOGICAL APPROACHES TOWARDS WATER WASTE MANAGEMENT saadmughal1271
This document discusses various biotechnological approaches for wastewater treatment, including engineered biosorbents for heavy metal removal, displaying metal binding peptides on microorganisms, and designing strains for enhanced biodegradation. It describes common wastewater treatment processes like the trickling filter, activated sludge process, and anaerobic digestion. Finally, it discusses using these biotechnological methods to treat wastewater from textile and desiccated coconut industries.
This document reviews the use of microalgae to biodegrade phenolic compounds in wastewater. It discusses how microalgae can remove over 70% of phenol from wastewater in a few days through metabolic pathways. The document also examines factors that affect microalgal growth, different culturing techniques like open and closed photobioreactor systems, and mechanisms by which microalgae degrade pollutants like phenol through the meta cleavage pathway. The conclusion emphasizes that microalgae significantly impact wastewater treatment and that understanding microorganism kinetics and mechanisms can further develop uses of microalgae for bioremediation.
This document defines a photobioreactor as a device that uses solar light to transform organic material into biomass. It discusses open and closed photobioreactor systems. Open systems include raceway ponds, which have lower costs but less control over conditions. Closed systems have reduced risks but higher costs. The document then describes five types of closed photobioreactors: tubular, Christmas tree, plate, horizontal, and foil designs. It notes advantages and disadvantages of different designs.
This document provides an overview of nanotechnology applications in food packaging. It discusses how nanomaterials can be incorporated into polymer packaging materials and coatings to improve barrier and antimicrobial properties. Key applications mentioned include polymer nanocomposites to enhance oxygen and moisture barrier properties, nano-coatings on packaging surfaces for improved barrier performance, and surface biocides using nanomaterials like silver, zinc oxide and titanium dioxide for their antimicrobial effects. The document also reviews the history of nanotechnology and various synthesis methods for nanomaterials.
Nanotechnology is the emerging technology in almost all fields of science ..It is preferred and studied due to its high efficiency in all fields of its application... Also being used in overcoming or eliminating environmental pollution to a greater level, this presentation is all about how Nanotechnology is useful in treating polluted water
Gonzalez, 2008, Sulfur Formation And Recovery In A Thiosulfate Oxidizing Bior...roelmeulepas
This article discusses a bioreactor system that allows for high production and recovery of elemental sulfur from thiosulfate oxidation. The system, called a Supernatant-Recycling Settler Bioreactor (SRSB), consists of an upflow bioreactor and separate aeration vessel. The bioreactor contains an internal settler and packing material to facilitate cell retention and settling of produced sulfur. Supernatant is continuously recirculated between the bioreactor and aerator. Testing achieved 98-100% thiosulfate conversion and a 77% elemental sulfur yield, with 93% of sulfur recovered from the bioreactor bottom as sludge containing 87% sulfur. The internal settler and packing
The document discusses environmental biotechnology and its applications. It provides details about (1) using microorganisms to treat hazardous wastes and pollution, including bioremediation of contaminated soil and water, (2) the treatment process at a common effluent treatment plant (CETP) that cleans waste water from textile industries, and (3) two case studies on bioremediation of oil-contaminated soil and waste water treatment at a CETP.
This document discusses concepts related to bioplastics and biodegradable plastics. It begins by defining conventional plastics and their properties, as well as bioplastics. There are two types of bioplastics - those derived from biomass and those that are biodegradable. The document then discusses standards for biodegradability and compostability, noting that current standards do not fully capture biodegradation under natural environmental conditions. It also suggests that industry groups have influenced standards and definitions in ways that overstate the sustainability and environmental friendliness of certain bioplastics. In summary, the document provides background on plastics and bioplastics, discusses standards and their limitations, and notes industry influence over definitions and standards
This document discusses nanoscience and nanotechnology applications in agriculture. It defines nanotechnology as controlling matter on an atomic and molecular scale between 1 to 100 nm. The document outlines several applications of nanotechnology in agriculture including controlled release of agrochemicals like fertilizers and pesticides, targeted delivery of biomolecules to plants, use of nanosensors to detect pathogens and monitor soil/plant growth, nanofertilizers to address nutrient deficiencies, nano-pesticides for effective pest control, nanoherbicides that target weed roots, and nanobarcodes for tracking agricultural products. The document also discusses using nanotechnology to recycle agricultural wastes and enhance biofuel production. While promising, the document notes nanotechnology raises
Nanotechnologies show potential for environmental cleanup through remediation of contaminated groundwater and soil. Specifically, injecting nanoparticles containing zero-valent iron (nZVI) underground can degrade pollutants in situ. However, the nZVI used is larger than true nanoparticles and behaves more like environmental colloids than nanoparticles. Its reactivity comes from high surface area rather than nanoscale effects, and it has limited mobility underground of only a few meters. More research is still needed to understand how nZVI transforms over time and impacts the environment.
Bioremediation - prospects for the future application of innovative appliedIvan Vera Montenegro
1) Bioremediation uses biological processes to eliminate, attenuate, or transform polluting substances. Traditional techniques like biopiling and landfarming rely on microbial degradation of contaminants in soil. Phytoremediation uses plants and their rhizospheres to uptake or degrade contaminants.
2) Phytobial remediation combines phytoremediation and bioremediation by using microbes like Trichoderma harzianum colonized in plant roots to efficiently degrade toxicants while providing an energy source from plant root exudates.
3) Initial experiments found T. harzianum could detoxify cyanides and metallocyanides in soil, allowing plant
1) Environmental biotechnology uses biological processes to study and benefit the natural environment, such as remediating pollution or developing green technologies.
2) Bioaccumulation occurs when organisms absorb substances like pesticides at a higher rate than they can eliminate them, resulting in increasing concentration of the substance in the organism's body over time.
3) Bioremediation uses microorganisms to remove pollutants from the environment, either on-site (in situ) or by removing contaminated material (ex situ). Examples include phytoremediation and bioleaching.
Characterization of Clay/Chitosan Nanocomposites and their Use for Adsorption...Editor IJCATR
The document describes a study that prepared nanocomposite films from chitosan biopolymer and montmorillonite nanoclay (MMT) at various weight percentages. XRD and FTIR were used to characterize the structural properties of the nanocomposites and showed an intercalated structure formed. The nanocomposites were then used to adsorb Mn(II) ions from aqueous solution. Parameters like pH, contact time, adsorption mass, initial concentration, and temperature were investigated. Adsorption isotherms and kinetics as well as thermodynamic properties of the process were analyzed.
Nanotechnology in waste water treatmentSakthivel R
This document discusses how nanotechnology can be used for waste water treatment. It explains that nanoparticles are effective at removing pollutants from water due to their high surface area. Various nanomaterials like metal nanoparticles, carbon nanomaterials, and zeolites can be used. Specifically, nano sorbents can sorbe a wide variety of organic and inorganic contaminants, nano catalysts can increase reaction rates to degrade contaminants, and biomimetic membranes allow for efficient desalination using reverse osmosis. Molecularly imprinted polymers also selectively remove pollutants even at low concentrations. Overall, nanotechnology provides effective, efficient, and eco-friendly approaches to water treatment.
This document discusses the development of a slow-release nitrogen fertilizer using hydroxyapatite nanoparticles modified with urea. Bench-scale testing showed the nanofertilizer provided slow release of nitrogen and improved phosphorus availability compared to granular urea alone. Field tests on rice crops demonstrated higher yields with the nanofertilizer when applied at 50% of the normal urea dosage. Use of such a nanofertilizer could help reduce urea losses estimated at 70% of usage in Sri Lanka, saving an estimated $44 million annually while minimizing environmental impacts.
1. Nanotechnology shows potential for improving water treatment through the use of nanomaterials for filtration, remediation, sensing, and disinfection. Various nanomaterials under research include carbon nanotubes, nanoparticles, and dendrimers for filtration and zeolites, carbon nanotubes, and nanoparticles for remediation.
2. While nanotechnology could address issues like water scarcity and quality, research is still needed to fully understand the toxicity of engineered nanoparticles. More data is needed on their environmental and health impacts before large-scale use in water applications.
3. Overall, nanotechnology represents an emerging area that may lead to novel solutions for water treatment through the unique properties of nanomaterials. However, more
This document discusses bioremediation, which uses microorganisms to return environments contaminated by pollutants to their original condition. It describes two types of bioremediation: in situ, which treats contamination on site, and ex situ, which treats contamination off site. In situ bioremediation can be intrinsic, occurring naturally over time, or engineered through additions to stimulate microbes. Ex situ involves removing contaminated waste and treating it through solid phase methods like composting or slurry phase systems in bioreactors. Key factors that affect bioremediation include moisture, pH, temperature, nutrients, contaminant concentration, and microbial populations.
The document discusses the use of NatureVel-WW, a bioaugmentation product, for wastewater treatment. It contains mixed cultures of beneficial microbes that work synergistically to break down organic compounds and reduce BOD, COD, and pathogens. The product is applied in initial booster doses and maintenance doses to inoculate treatment systems and ensure the introduced microbes dominate over indigenous populations, improving system efficiency and reliability while reducing sludge and odors.
This document reviews the use of nanotechnology for waste water treatment. It discusses how nanoparticles have a high surface area and unique properties that allow them to efficiently remove toxins, microbes, and other contaminants from water. Various nanomaterials can be used, including metal nanoparticles, carbon nanomaterials, zeolites, and dendrimers. The document summarizes recent research on nanostructured catalytic membranes, nanosorbents, nanocatalysts, bioactive nanoparticles, biomimetic membranes, and molecularly imprinted polymers for applications in water treatment. Nanotechnology approaches provide efficient, precise, and scalable ways to treat waste water with benefits like lower costs and energy usage compared to conventional methods. However, more research is
The document discusses bioremediation of industrial wastewater using Pseudomonas aeruginosa. It provides background on the increasing volume of industrial wastewater polluting water sources and the need for effective treatment. The study aims to assess water quality parameters like BOD, COD, pH, TSS, TS and alkalinity before and after bioremediation of wastewater using P. aeruginosa over 15 days. The results will show if this microorganism can decrease waste and help treat industrial wastewater.
This document discusses bioaugmentation as a remediation technology. It introduces bioaugmentation and describes different bioaugmentation technologies including cell bioaugmentation, gene bioaugmentation, rhizosphere bioaugmentation, and phytoaugmentation. Cell bioaugmentation involves using carrier materials or encapsulation to deliver microorganisms to contaminated sites. Gene bioaugmentation uses horizontal gene transfer to introduce remediation genes. The document also provides case studies of bioaugmentation in coke plant wastewater and oilfield wastewater treatment and discusses benefits and challenges of bioaugmentation.
BIOTECHNOLOGICAL APPROACHES TOWARDS WATER WASTE MANAGEMENT saadmughal1271
This document discusses various biotechnological approaches for wastewater treatment, including engineered biosorbents for heavy metal removal, displaying metal binding peptides on microorganisms, and designing strains for enhanced biodegradation. It describes common wastewater treatment processes like the trickling filter, activated sludge process, and anaerobic digestion. Finally, it discusses using these biotechnological methods to treat wastewater from textile and desiccated coconut industries.
This document reviews the use of microalgae to biodegrade phenolic compounds in wastewater. It discusses how microalgae can remove over 70% of phenol from wastewater in a few days through metabolic pathways. The document also examines factors that affect microalgal growth, different culturing techniques like open and closed photobioreactor systems, and mechanisms by which microalgae degrade pollutants like phenol through the meta cleavage pathway. The conclusion emphasizes that microalgae significantly impact wastewater treatment and that understanding microorganism kinetics and mechanisms can further develop uses of microalgae for bioremediation.
This document defines a photobioreactor as a device that uses solar light to transform organic material into biomass. It discusses open and closed photobioreactor systems. Open systems include raceway ponds, which have lower costs but less control over conditions. Closed systems have reduced risks but higher costs. The document then describes five types of closed photobioreactors: tubular, Christmas tree, plate, horizontal, and foil designs. It notes advantages and disadvantages of different designs.
This document provides an overview of nanotechnology applications in food packaging. It discusses how nanomaterials can be incorporated into polymer packaging materials and coatings to improve barrier and antimicrobial properties. Key applications mentioned include polymer nanocomposites to enhance oxygen and moisture barrier properties, nano-coatings on packaging surfaces for improved barrier performance, and surface biocides using nanomaterials like silver, zinc oxide and titanium dioxide for their antimicrobial effects. The document also reviews the history of nanotechnology and various synthesis methods for nanomaterials.
FABRICATION OF A SIMPLE BUBBLE COLUMN CO2 CAPTURE UNIT UTILIZING MICROALGAE ijbbjournal
This paper focuses on the fabrication of a vertical column CO2 bioreactor and the experimentation of
microalgae. On the manufacturing aspect of the project, the base design was modelled on Solidworks and
assigned a material. The model was then loaded onto a finite element analysis (FEA) software to determine
various engineering stresses and strains to confirm the specimen’s strength. Once the simulation had
completed, the model was ready for 3-D printing. The species of microalgae to be used in this study was
Chlorella Vulgaris. The medium solution was prepared by mixing many types of salts suitable for this type
of algae. Experimental trials of algae growth were conducted mainly to see whether the algae would indeed
grow more rapidly using the developed medium. After failure in early trials, some experiments were
conducted to determine which concentration of stock solution would be the most ideal for the algae to grow
in. These early experiments proved the major impacts of the concentration of the medium on the rate of
growth of the algae. The knowledge gained in these experiments will be instrumental during the next stages
of this project.
FABRICATION OF A SIMPLE BUBBLE COLUMN CO2 CAPTURE UNIT UTILIZING MICROALGAEijbbjournal
This document summarizes the fabrication of a vertical column photobioreactor to capture CO2 using microalgae. It describes the design and 3D printing of the reactor base, cultivation of Chlorella Vulgaris microalgae in the reactor, and experimental trials testing different growth medium concentrations. The best growth was found at a 20% concentration. The reactor design aims to efficiently capture CO2 from flue gases through microalgae photosynthesis in a controlled environment.
It is strongly felt the need to replace fossil fuels with other renewable and more compatible with the environment. The spinneret of algal crops is
producing different solutions ("open ponds", tubular, bioreactors in greenhouses, etc.). The aim is to obtain concentrations of dry substance such as to
justify the high costs of extraction. Another limitation suffered by the actual plants, derives from the choice to move the algal mass (process
characterized by a high energy consumption), with actions necessary to keep it in suspension as well as to move it, to exchange its positioning in order
to bring it to be conditioned by the light (exhausting its effectiveness after the first 0.2-0.3 m of algal mass depth, or even less if thicker and when it
would need more light for its exponential growth). In particular, it is not possible to bring a specific radiation spectrum, in a pervasive and deep way,
with a drastic cost reduction for the mechanical movement of the culture medium. A limitation derives also from the possibility of biological and
chemical contamination from the environment, because the algal mass is in a large contact with the environment itself (e.g. the "open ponds"
situations) and it is heavily exposed to the prevalent thermal cycles (often not suitable to the processes of growth) inside it. Some problems are often
encountered even in the phase of collection and selection of the algal mass to be forwarded to the following processes, that proceeds through the
massive processing of large volumes (by filtration and concentration) that, due to previous limitations (contamination and uncertain conditions of
growth), remain at low concentrations. The purpose of this article is to present the PBRC (Photo Bio Reactor Continuous) plant, subject of an
Italian patent [Lavanga and Farné, 2014], for the cultivation of microalgae, from which to extract an oleic fraction, which can be destined for
production of biofuels, and a protein fraction, which can be destined for use in the chemical, agri-food, pharmaceutical and cosmetic sectors.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document provides an overview of nanotechnology including definitions, history, and applications. It defines nanotechnology as the design and manipulation of materials at the nanoscale (1-100 nm) to produce novel properties. Nanomaterials are characterized by their small size and increased surface area. The document outlines the bottom-up and top-down approaches to nanotechnology and gives examples of applications in various fields including medicine, computing, and the environment. It specifically discusses applications of nanotechnology for water purification such as detection, filtration membranes, and biofilm removal. The document concludes with noting both the promise and environmental implications of nanotechnology that require further study.
Biological and Advanced Water Treatment.pptxYalelet Abera
Micro-organisms play an essential role in the biological treatment of wastewater by converting organic waste into more stable substances. There are three main types of biological wastewater treatment processes - aerobic, anaerobic, and anoxic. Two common biological wastewater treatment methods are trickling filters and activated sludge processes. Trickling filters use microorganisms attached to media to treat wastewater as it trickles down. Activated sludge processes use air and microorganisms in suspension to treat wastewater in aeration tanks, with the treated wastewater then sent to secondary clarifiers. Design considerations for biological wastewater treatment systems include organic loading rates, hydraulic loading rates, and detention
A bioreactor is an installation for the production of microorganisms outside their natural but inside an artificial environment. The prefix “photo” particularly describes the bio-reactor's property to cultivate phototrophic microorganisms, or organisms which grow on by utilizing light energy.
These organisms use the process of photosynthesis to build their own biomass from light and carbon dioxide. Members of this group are Plants, Mosses, Microalgae, Cyanobacteria and Purple Bacteria.
Photobioreactor or PBR, is the controlled supply of specific environmental conditions for respective species.
Photobioreactor allows much higher growth rates and purity levels than anywhere in natural or habitats similar to nature.
The function of the bioreactor is to provide a suitable environment in
which an organism can efficiently produce a target product—the target product might be.
Cell biomass
Metabolite
Bioconversion Product
The performance of any bioreactor depends on the following key factors:
Agitation rate
Oxygen transfer
pH
Temperature
There is no universal bioreactor.
The general requirements of the bioreactor are as follows:
The design and construction of bioreactors must keep sterility from the start point to end of the process.
Optimal mixing with low, uniform shear.
Adequate mass transfer, oxygen.
Clearly defined flow conditions.
Feeding substrate with prevention of under or overdosing.
Suspension of solids.
Gentle heat transfer.
Compliance with design requirements such as: ability to be sterilized; simple construction; simple measuring, control, regulating techniques; scale-up; flexibility; long term stability; compatibility with up- downstream processes; antifoaming measures.
A STUDY ON REDUCTION OF NITRATE FROM INDUSTRIAL CUM MUNICIPAL WASTEWATER USIN...IRJET Journal
1. The document discusses using MBBR technology to remove nitrates from industrial and municipal wastewater using polyurethane sponge bio-carriers.
2. It summarizes previous studies that found MBBR with PU carriers can achieve simultaneous nitrification and denitrification to efficiently remove total nitrogen at low levels.
3. The document also reviews literature that showed increasing the packing fraction of PU sponge carriers in an MBBR reactor improved nitrate removal through SND processes.
Bioremediation uses microorganisms or plants to remove pollutants from the environment. There are two main types - in situ treats pollutants on site, while ex situ removes pollutants to off-site facilities. Examples of in situ techniques include bioventing, biosparging, and in situ biodegradation which supply oxygen and nutrients to stimulate bacteria. Ex situ methods include slurry and aqueous reactors which process contaminated materials in a contained system. Bioremediation can degrade pollutants like copper but has limitations such as environmental constraints and long treatment time.
Photobioreactors Harnessing Photosynthesis for Sustainable Innovation.Fermex Solutions LLP
Discover the fascinating world of Photobioreactors. These innovative systems harness the power of light and microorganisms to produce biofuels, nutraceuticals, and more. Explore their design, advantages, and applications in a concise 50-word description that will leave you eager to learn more about this sustainable technology.
Major Project -Development of Nano Water FilterZiyad Sayed
Water is essential for life on Earth. However, only 1% of the world's fresh water is accessible for direct human use. As a result, over 1 billion people lack access to drinking water. Shortages are caused by factors like water pollution from agricultural and industrial runoff. This document proposes using a water purifier with UV disinfection, activated carbon filtration, and a polypropylene membrane to provide clean drinking water. Titanium dioxide coating on activated carbon and membranes could improve purification by photo catalytically degrading pollutants under UV light. Experiments are described to synthesize and apply these materials.
How nanotechnology affect biodiversity and ecosystem by shreya modiShreya Modi
This document discusses how nanotechnology can help address issues related to biodiversity and ecosystems. It describes how nanotechnology can help develop sustainable energy sources, treat wastewater, aid in oil spill cleanup, and enable better and more affordable medical treatment. The document provides multiple examples of how nanomaterials and nanoscale processes are already being used or explored to solve environmental problems and support human health and well-being while reducing environmental impacts.
Treatment of High Strength Industrial Effluents Using Levapor Bio Carriers fo...Amit Christian
This document discusses the biotreatment of industrial effluents using LEVAPOR biofilm technologies. It outlines that industrial effluents contain a variety of pollutants that are difficult to treat with conventional methods. The document then describes how LEVAPOR utilizes biomass immobilization to create biofilms that are highly resistant to toxic pollutants. This allows for effective degradation of even slowly degradable and toxic compounds. Several case studies are presented showing high removal rates of pollutants like bisphenol-A from industrial wastewaters using LEVAPOR biofilm reactors and biofilters.
Applications of nanotechnology in food packaging and food safetyDr. IRSHAD A
Over the past few decades the evolution of a number of science disciplines and technologies have revolutionized food and processing sector. Most notable among these are biotechnology, information technology etc… and recently nanotechnology which is now constantly growing in the field of food production, processing, packaging, preservation, and development of functional foods. Food packaging is considered as one of the earliest commercial application of nanotechnology in food sector. Around more than 400 Nanopackaging products are available for commercial use. In 2008, nanotechnology demanded over $15 billion in worldwide research and development money (public and private) and employed over 400,000 researchers across the globe (Roco, M. C. et al. 2010). Nanotechnologies are projected to impact at least $3 trillion across the global economy by 2020, and nanotechnology industries worldwide may require at least 6 million workers to support them by the end of the decade (Roco, M. C. et al. 2010). Scientists and industry stakeholders have already identified potential uses of nanotechnology in virtually every segment of the food industry from agriculture (e.g., pesticide, fertilizer or vaccine delivery; animal and plant pathogen detection; and targeted genetic engineering) to food processing (e.g., encapsulation of flavor or odor enhancers; food textural or quality improvement; new gelation or viscosifying agents) to food packaging (e.g., pathogen, gas or abuse sensors; anticounterfeiting devices, UV-protection, and stronger, more impermeable polymer films) to nutrient supplements (e.g., nutraceuticals with higher stability and bioavailability). Undeniably, the most active area of food nanoscience research and development is packaging: the global nano-enabled food and beverage packaging market was 4.13 billion US dollars in 2008 and has been projected to grow to 7.3 billion by 2014, representing an annual growth rate of 11.65% (www.innoresearch.net).This is likely connected to the fact that the public has been shown in some studies to be more willing to embrace nanotechnology in ‘out of food’ applications than those where nanoparticles are directly added to foods.
This document discusses bioreactors and their applications in waste water treatment. It begins with an introduction to bioreactors and their role in biotechnology. It then describes different types of bioreactors, including suspended growth reactors like batch and continuous stirred-tank reactors, as well as biofilm reactors like packed bed and fluidized bed reactors. The document concludes by discussing various applications of bioreactors in treating gaseous, liquid and solid wastes through bioconversion.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The development of sustainable bioplastics for new applications in packaging ...Agriculture Journal IJOEAR
Abstract— The advantage of biodegradable plastics is their degradation under the influence of biological systems into substances naturally present in the environment, which are then placed in a natural circulation cycle of matter. Moreover, the biodegradable plastics waste not require additional segregation and separation from households, and are collected together with other organic waste and subjected to recycling under aerobic or anaerobic conditions. Use of bioplastics reduces the harmful effects of waste on the environment, but does not eliminate it completely.
The article presents the results of (bio) degradation studies under industrial and laboratory (MicroOxymax) composting conditions as well as at atmospheric conditions of commercial disposable dishes from the Nature Works® PLA. Were also carried out investigation of abiotic degradation under laboratory conditions. It was found, from the macro- and microscopic observations, that the tested cups (bio) degraded in the selected environments, wherein in a greater extent under industrial composting conditions than in MicroOxymax. The GPC results, which show significantly reduce in the molar mass of the tested samples after specified incubation times in all environments, indicates that the hydrolytic degradation process occurs predominantly.
Similar to O pulz photobioreactor_productionsystem (20)
2. Fig. 1 Typical open pond
production site using a raceway
arrangement
Table 1 Systematics of
cultivation equipment Basic type Technical variables
1. Open system
Cuvette, container, stirred vessel Material (glass, plastics)
Natural water Turbulence development (pumping, stirring)
Raceway pond Flow direction (horizontal/vertical)
Inclined surface device Surface to volume-ratio
2. Closed system
Plastic sleeves O2 removal > CO2 input
Fermenter-like tank Type and duration of illumination
Tubular PBR Temperature control
Laminar PBR Sterilization
usually operating at water depths of 15–20 cm (Fig. 1). Closed systems
At these water depths, biomass concentrations of up to
1,000 mg/l and productivities of 60–100 mg/(l day–1), Closed PBRs are characterized by the regulation and
i.e., 10–25 g/(m2 day–1), is possible. Similar in design control of nearly all the biotechnologically important
are the circular ponds which are common in Asia and the parameters as well as by the following fundamental
Ukraine (Becker 1994). benefits (Pulz 1992): a reduced contamination risk,
Significant evaporative losses, the diffusion of CO2 to no CO2 losses, reproducible cultivation conditions,
the atmosphere. as well as the permanent threat of controllable hydrodynamics and temperature, and flexible
contamination and pollution, are the major drawbacks of technical design.
open pond systems. Also, the large area required must The scale-up of simple closed container-based
not be underestimated. The main disadvantage of this systems (tanks, hanging plastic bags) as a first generation
principle in terms of productivity seems to be the light of closed PBRs was soon faced with serious limitations
limitation in the high layer thickness. Technically it is because at a volume of 50–100 l it is no longer possible
possible to enhance light supply by reducing the layer to effectively introduce the light energy required for
thickness to a few centimeters or even millimeters, using successful biomass development. Several technical
thin layer inclined types of culture systems. Another approaches to underwater lighting, for instance with
problem of open systems is the maintenance of the submersed lamps or light diffusing optical fibers on the
desired microalgal population, which is possible only for one hand, or with pillar-shaped photobioreactors on the
extremophilic species and even there some contamina- other hand, have been tried, but have not been successful
tion risks remain. in application (Gerbsch et al. 2000; Semenenko et al.
Until recently, open systems were the most important 1992). However, this principle seems to be of future
design principle for microalgal production (Richmond relevance only for the aquaculture of certain selected
1990). However, the preparation of high-value products species.
from microalgae for applications in pharmacy and Closed photobioreactors (Fig. 2) are currently tested for
cosmetics appears to be feasible only on the basis of closed microalgal mass cultures in the following configurations:
photobioreactors with the ability to reproduce production (1) tubular systems (glass, plastic, bags), (2) flattened,
conditions and to be GMP-relevant (GMP: good manu- plate-type systems, and (3) ultrathin immobilized configu-
facturing practice following ISO and EC guidelines). rations. Vertical arrangements of horizontal running
3. tubes or plates seem to be preferred for reasons of light
distribution and appropriate flow.
Since about the 1990s, parameters such as species-
efficient light incidence into the photobioreactor lumen,
light path, layer thickness, turbulence and O2 release
from the total system volume have gained in importance
(Table 2). Closed or almost closed systems based on very
different design concepts have already been implemented
and tested up to pilot scale. The latest developments
seem to be directed toward photobioreactors of a tubular
configuration or of the compact-plate type as well as
combinations of these main design principles in order to
distribute the light over an enlarged surface area (Tredici
and Materassi 1992; Gabel and Tsoglin 2000).
Assuming that light for photosynthesis should be
continuously available to the receptor in the microalgal
cell, a lamination or other enlargement of the reactor
surface directed toward the light source seems to be the
prime aim. For microalgae this idea may include an
appropriate lowering of net light energy supply for the
suspension because of the significantly lower level of
light saturation needed for these organisms. The basic
principle of the laminar concept for thin layer plate or
thin diameter tube photobioreactors mimics the leaves of
higher plants. For instance a 100-year-old,10 m high
lime tree shading an area of 100 m2 has a leaf surface
area of more than 2,500 m2. Expressed as a surface:
volume ratio this amounts to a value of 2.5 m2/m3.
On the basis of these considerations, the trend toward
developing closed photobioreactors as already described
Fig. 2 Closed plate type photobioreactor fed with high CO2 levels
from a lime production plant in central Germany is paralleled by conceptions of the use of relatively thin
light-exposed reactor lumina. The tube diameter in tubular
photobioreactors is reduced significantly and laminar,
Table 2 Advantages and disadvantages of open and closed algal cultivation plants
Parameter Open ponds (raceway ponds) Closed systems (PBR systems)
Contamination risk Extremely high Low
Space required High Low
Water losses Extremely high Almost none
CO2-losses High Almost none
Biomass quality Not susceptible Susceptible
Variability as to cultivatable Not given, cultivation possibilities High, nearly all microalgal varieties
species are restricted to a few algal varieties may be cultivated
Flexibility of production Change of production between Change of production without
the possible varieties nearly impossible any problems
Reproducibility of production Not given, dependent on exterior conditions Possible within certain tolerances
parameters
Process control Not given Given
Standardization Not possible Possible
Weather dependence Absolute, production impossible during rain Insignificant, because closed configurations
allow production also during bad weather
Period until net production is reached Long, approx. 6–8 weeks Relatively short, approx. 2–4 weeks
after start or interruptions
Biomass concentration during production Low, approx. 0.1–0.2 g/l High, approx. 2–8 g/l
Efficiency of treatment processes Low, time-consuming, large volume flows due High, short-time,
to low concentrations relatively small volume flows
4. Table 3 Basic values of various cultivation plants (data obtained from IGV: German cultivation sites at natural illumination)
Unit Raceway Incl. Surface type Tubular Plate
Open pond, high Open pond, low
layer thickness layer thickness Semi-closed Semi-closed
tubular system plate system
Illuminated surface m2 500 200 600 500
Total volume m3 75 5 7 6
Space required m2 550 250 110 100
Layer thickness cm 10–30 0.5–1 4 3
Flow rate cm s–1 30–55 30–45 50–60 120
Biomass conc.(DW) mg l–1 300–500 3,000–6,500 5,000–8,000 5,000–8,000
Productivity (DW) g l–1 d–1 0.05–0.1 0.8–1.0 0.8–1.2 0.8–1.3
plate-type configurations are strongly favored. The tubular proportional to light intensity, until at high illumination
or pipe design principle is the most important basis of intensities damage to the photosynthetic receptor system
completely or partially closed cultivators in plastic ducts occurs within a few minutes (photoinhibition). In most
and especially in glass or plastic tubes. The development microalgae, photosynthesis is saturated at about 30% of the
of closed photobioreactors, which had intensified by the total terrestrial solar radiation, i.e. 1,700–2,000 µE/(m2 s).
end of the 1980s, seems to be of significant future Some picoplankton species grow with optimal rates at
importance. Compared with laminar, plate-type systems, 50 µE/(m2 s) and are photoinhibited at 130 µE/(m2 s).
the tubular systems seem to have identical configuration Phanerophytes, like most agricultural crops with light
potentials, especially in cases of vertical packing of limitation values of 900 µE/(m2 s), are clearly adapted to
horizontally oriented tubes (Broneske et al. 2000; Molina higher PFD than microalgae are.
Grima et al. 2000; Table 3). Stirred fermenters illuminated with various submersed
luminous elements or light pipes facilitate an average
productivity in the range of 100–1,000 mg DW/(1 day).
Biotechnological problems and preconditions This appears to be the upper limit at a surface :volume
for PBR design ratio of 2–8 m2/m3 typical for this illumination design.
Laboratory bioreactors based on this principle are very
The normal, i.e., natural life conditions of microalgae well suited to physiological and autecological studies as
which are subject to biotechnological research, are as well as for the establishment and testing of miniature
follows: maximum cell densities of 103 cells/ml, average ecosystems, but they cannot be used for scaling up. In
distance between cells of 1,350 µm or 250 times the cell tubular or plate-type photobioreactors, surface:volume
diameter, vertical or horizontal displacements of 5×10–3 ratios of 20–80 m2/m3 and light incidence values (PAR)
to 3×10–5 m/s, photon flux density (PFD) usually well up to 1,150 µE/(m2 s) are achieved. At a layer thickness
within the light limited area, light supply subject to of up to 5 mm, a productivity of 2–5 g DW/(l day) can
daytime rhythm, CO2 and nutrient conditions, generally be achieved (Chini Zitelli et al. 2000).
far from optimal, and prolonged stability of pH value, Despite growing interest in recent years, there are
ion concentrations and temperature. only a few references in the literature regarding the
In contrast, for cultivation systems, we have to apply short-term processes of photoadaptation, on light inhibition
very different conditions, namely: cell densities up to 108 or saturation effects in closed photobioreactors. Photo-
cells/ml, average distance between cells reduced to adaptation requires at least 10–40 min, which can explain
60 µm or 10 times the cell diameter, spatial displacements the discrepancy between the productivity of open-air
ranging from 0.3 to 1.2 m/s, turbulence-conditioned PFD algal cultures and their light optimum. Photoinhibitory
variations with frequencies of 0.1–1,000 s superseding processes, too, are time-dependent; however, in this case
the daytime rhythm, generally optimum or surplus nutrient irreversible destruction is supposed to occur even after
and CO2 supply, pH values and temperatures undergoing only a few minutes of light stress, exceeding 50% damage
completely nonphysiological variations, and nearly after 10–20 min.
continuous mechanical stress on the cell walls and the
cells themselves (Tredici 1999).
CO2/O2 balance
Light energy For a high photosynthesis rate, the CO2/O2-balance has
to be adjusted in a way that the prime carboxylating
Light as the energy source for photoautotrophic life is enzyme, Rubisco, furnishes CO2 for the Calvin cycle but
the principal limiting factor in photobiotechnology (Kirk does not use O2 for photorespiration. Hence, in algal
1994). At illumination intensities above the light cultures of high cell densities, sufficient CO2 must be
compensation point the rate of photosynthesis is directly available, while evolved O2 has to be removed before
5. Temperature
Temperature influences respiration and photorespiration
more strongly than photosynthesis. When CO2 or light is
limiting for photosynthesis, the influence of temperature
is insignificant. With an increase in temperature, respira-
tion will rise significantly, but the flux through the
Calvin cycle increases only marginally. Thus, the net
efficiency of photosynthesis declines at high temperatures.
This effect can worsen in suspension cultures by the
difference in decrease of CO2 and O2 solubility at elevated
temperatures.
Salinity, nutrients, and pH-value
A sufficient nutrient supply for microalgae is a precondi-
Fig. 3 Small size commercial photobioreactor of 25 l with tubular, tion for optimal photosynthesis. Deficiencies will cause
sterilizable design disturbances in metabolism and disproportionate produc-
tion of intermediates of photosynthesis. Deviations from
the optimum pH, osmotical conditions and salinity will
reaching inhibitory concentrations. The complete avoid- cause physiological reactions and productivity problems.
ance of photorespiration, however, remains unsolved. Therefore, these easily controllable conditions should
Oxygen may become a problem in algal cultures of be maintained in optimum ratios in photobioreactors.
high cell densities not only because of the limitation of Organic carbon sources seem to be important for some
the rate of photosynthesis. In cultures of microalgae mixotrophic or even pure heterotrophic microalgal biomass
optimally supplied with CO2 the O2 production can easily production systems. Therefore, organic wastes as well as
reach concentrations of up to 40 mg/l. Upon radiation pure simple organic substances like acetic acid or various
with appropriate energy, oxygen radicals may develop sugars have been investigated for their possible use in
during the respiratory gas exchange and cause toxic microalgal production.
effects on cells due to membrane damage. Superoxide
dismutases and other O2 radical neutralizing systems may
have a protective effect. In high-cell-density microalgal Turbulence
cultures with optimum growth, species-specific O2 evolu-
tion rates between 28 and 120 mg O2/(g DW h–1) were Photoautotrophic nano- and microplankters live in their
recorded. Many algal strains cannot survive in significantly natural environment at a density of 103 cells/ml and at
O2-oversaturated milieu longer than 2–3 h. High tempera- distances of more than 1,000 µm between cells. Thus,
tures and PFDs, combined with CO2 limitation, will in high-cell-density microalgal cultures of up to 109
intensify the physiological inhibitory processes (Fig. 3). cells/ml, the natural conditions are not suitable for
CO2-concentrations usually have to be kept within high productivity (Borowitzka and Borowitzka 1988;
narrow margins. While a 0.03% CO2 content in air is Grobbelaar 2000).
suboptimal for plant growth, most plants will tolerate
CO2 concentrations only up to 0.1%. However, for many
strains of microalgae it was observed that they tolerate Photobioreactors of pilot to industrial scale
up to 12% CO2 at a temperature of 35°C. At present,
partial pressure of O2 (pO2) in microalgal suspensions For aquaculture applications, many taxonomically very
inside both open and closed photobioreactors may be different species of microalgae are produced, mostly
reduced only by (1) increasing turbulence, and (2) O2 locally. Both advanced open systems in the form of plastic
stripping with air. Both approaches imply an “unsolved sleeves, plastic pillars and containers are used, in many
dilemma” in the reactor system: Although an intensive cases as one-way systems. But because of the high costs
search for membranes suitable for gas exchange is of these systems combined with poor productivity,
underway, no breakthrough has yet been reported. At closed systems like tubular PBR (Biocoil, Biofence,
present, sufficient CO2 transitions on membranes can be ultrathin sheets) are gaining economic importance
provided only under pressure, otherwise the transition (Richmond 2000).
proceeds slowly along the gradient. Production using conventional fermenters with
An alternative may be the relatively simple injection microalgae-related organisms like Crypthecodinium
of small amounts of pure CO2 into high-cell-density under heterotrophic conditions appears to be of economic
microalgal cultures with biomass concentrations of 8–10 g interest for the production of polyunsaturated fatty acids.
dry weight (DW)/l (Straka et al. 2000). However, this method involves routine techniques of
6. Fig. 4 Natural lake in Myanmar producing Spirulina-biomass
Fig. 5 700 m3 glass tube photobioreactor producing Chlorella
heterotrophic biotechnology and not photobioreactors. biomass
Even today the approximately 5,000–6,000 t/a dry biomass
of microalgae produced worldwide originates mainly closed tubular PBR systems in Germany (Dilow 1985;
from open systems. These open systems (Fig. 4) include Borowitzka and Borowitzka 1988; Apt and Behrens
natural waters as well as unstirred but constructed ponds 1999).
and circular or raceway ponds. After an upscaling period of nearly 3 years, a tubular
Aphanizomenon and Nostoc, two rather uncommon system on an industrial scale was established in the year
genera, are exclusively harvested from natural waters; 2000 near Wolfsburg, Germany (Fig. 5). This closed
Aphanizomenon only in the US for health food, Nostoc system is apparently the largest PBR to have gone into
in many Asian countries for food. successful production. It consists of compact and vertically
The green alga Haematococcus has attained a total of arranged horizontal running glass tubes of a total length
approximately 50 t/a for astaxanthin production using a of 500,000 m and a total PBR volume of 700 m3. In a
combination of closed and open systems. This alga has glasshouse requiring an area of only 10,000 m2 an annual
great potential as a future crop for aquaculture. production of 130–150 tonnes dry biomass was demon-
Dunaliella is produced in natural ponds in Australia strated to be economically feasible under Central European
and in smaller amounts in the Ukraine, in earthwall-lined conditions.
unstirred ponds in Australia and also in raceway-ponds
in Israel and the United States. In all cases carotinoids
are the prime products. Conclusion
In terms of overall production Spirulina (Arthrospira)
seems to be the most important microalgal species and For the mass culture of microalgae, open pond systems
this is produced nearly exclusively in open systems, have mainly been the dominating systems up until now.
though there have been some efforts to establish a However, closed systems of light-distributing tube or
commercial Spirulina culture under temperate climatic plate design, known as photobioreactors, are now
conditions (Brouers 2000). The most famous, nearly increasingly finding new applications both for high-
natural open pond production facility was Lake Texcoco value products in pharmacy and cosmetics as well as for
in Mexico with considerable Spirulina production in the aqua- and agricultural uses.
past. This facility was closed in 1994/95 because of
problems with contamination and pollution. In recent
years crater lakes in Myanmar (Burma) have gained References
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