The document discusses the potential for white rot fungi, such as Phanerochaete sordida YK-624 and P. chrysosporium IFO31249, to bioremediate polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs). Experiments showed that both fungi were capable of degrading between 70-75% of various PCDDs and PCDFs within 14 days when supplemented with glucose and oxygen. The degradation occurred through non-specific extracellular enzymes and showed no clear dependence on substrate structure. Care was taken to prevent evaporation and exposure during the experiments.
Low density polythene (LDPE) is the most widely used packaging material primarily because of its excellent mechanical properties, barrier properties against water, light weight, low cost and high energy effectiveness.
LDPE to biological attack was believed to be contributed by the hydrophobic carbon backbone and high molecular weight of the polymer. Thus, over the years, the rapid biodegradation of plastic has been a subject of interest in the waste management problem.
Each year, an estimated 500 billion to 1 trillion plastic bags are consumed worldwide. After their use, these packaging materials are dumped in landfills leading to pollution since they are non-biodegradable under natural environmental conditions
With the expansion and development of the aquaculture industry, several challenges arise. The intensification of production systems increases the pressure on the environment, which can severely affect water quality and as a consequence fish or shrimp performance and the incidence of diseases.
Biorestoration deals with restoring or bringing back to an original or near original state using living micro-organisms. Nature has a built in check and balance system in everything it does. If there is too much or too little of something nature will use various life forms to try to re-establish a balance
Low density polythene (LDPE) is the most widely used packaging material primarily because of its excellent mechanical properties, barrier properties against water, light weight, low cost and high energy effectiveness.
LDPE to biological attack was believed to be contributed by the hydrophobic carbon backbone and high molecular weight of the polymer. Thus, over the years, the rapid biodegradation of plastic has been a subject of interest in the waste management problem.
Each year, an estimated 500 billion to 1 trillion plastic bags are consumed worldwide. After their use, these packaging materials are dumped in landfills leading to pollution since they are non-biodegradable under natural environmental conditions
With the expansion and development of the aquaculture industry, several challenges arise. The intensification of production systems increases the pressure on the environment, which can severely affect water quality and as a consequence fish or shrimp performance and the incidence of diseases.
Biorestoration deals with restoring or bringing back to an original or near original state using living micro-organisms. Nature has a built in check and balance system in everything it does. If there is too much or too little of something nature will use various life forms to try to re-establish a balance
Biodegradation and Bioremediation, an environmental friendly treatment methods to sustain natural environment unchanged. This is the Reliable, and cost effective application.
Bioremediation and Biodegradation of Hydrocarbon Contaminated Soils: A Reviewiosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online
Control of pollution by genetically engineered microorganismsSamar Biswas
Pollution refers to the presence of a substance or substances in the environment that are harmful or toxic. The substances or pollutants may be harmful to human health, other animals, and plants. When something harmful enters the environment at a faster rate that it can be dispersed, there is pollution.
A pesticide can be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
Pesticides like insecticides, herbicides, fungicides, and various other substances are used to control or inhibit plant diseases and insect pests.
The positive aspect of application of pesticides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases.
However excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards.
Due to these problems, development of technologies that guarantee their elimination in a safe, efficient and economical way is important.
BIOREMEDIATION?
What Is BIOREMEDIATION?
Potential hazards
Mechanism of Bioremediation
Types Of Bioremediation
CONTAMINANTS ..BREAK DOWN BIOREMEDIATION
Microorganisms (Pure cultures) helpful in bioremediation
BIOREMEDIATION TECHNOLOGIES
In situ bioremediation Techniques
.BIOVENTING
BIOAUGMENTATION
BIOSPARGING
Ex situ bioremediation Techniques
LAND FARMING
COMPOSTING
BIOREACTORS
Advantages of Bioremediation
Disadvantages to Bioremediation
Bioremediation is the process in which the micro-organisms are used to degrade the pollutants from the environment. Plants and micro-organisms are used to clean up the environment. Bioremediation is carried out by microbes and their metabolisms are used to remove the contaminants. Microbes have the ability to resolve the issue of contaminated ecosystem1. To improve or better living style the degradation of contaminated areas is very important. Importance of the biodegradation is increasing due to the expensiveness of the chemicals. So bioremediation is the best choice. The effluents should be degraded from the environment because they are very dangerous and have a bad impact on human beings. These pollutants sink into the water and cause pollution. These pollutants are treated with the help of microbes in bioremediation process. It is the best method because it is cost effective and eco-friendly. Different techniques of bioremediation are used to convert toxic substances into less toxic substances.
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
Biodegradation and Bioremediation, an environmental friendly treatment methods to sustain natural environment unchanged. This is the Reliable, and cost effective application.
Bioremediation and Biodegradation of Hydrocarbon Contaminated Soils: A Reviewiosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online
Control of pollution by genetically engineered microorganismsSamar Biswas
Pollution refers to the presence of a substance or substances in the environment that are harmful or toxic. The substances or pollutants may be harmful to human health, other animals, and plants. When something harmful enters the environment at a faster rate that it can be dispersed, there is pollution.
A pesticide can be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
Pesticides like insecticides, herbicides, fungicides, and various other substances are used to control or inhibit plant diseases and insect pests.
The positive aspect of application of pesticides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases.
However excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards.
Due to these problems, development of technologies that guarantee their elimination in a safe, efficient and economical way is important.
BIOREMEDIATION?
What Is BIOREMEDIATION?
Potential hazards
Mechanism of Bioremediation
Types Of Bioremediation
CONTAMINANTS ..BREAK DOWN BIOREMEDIATION
Microorganisms (Pure cultures) helpful in bioremediation
BIOREMEDIATION TECHNOLOGIES
In situ bioremediation Techniques
.BIOVENTING
BIOAUGMENTATION
BIOSPARGING
Ex situ bioremediation Techniques
LAND FARMING
COMPOSTING
BIOREACTORS
Advantages of Bioremediation
Disadvantages to Bioremediation
Bioremediation is the process in which the micro-organisms are used to degrade the pollutants from the environment. Plants and micro-organisms are used to clean up the environment. Bioremediation is carried out by microbes and their metabolisms are used to remove the contaminants. Microbes have the ability to resolve the issue of contaminated ecosystem1. To improve or better living style the degradation of contaminated areas is very important. Importance of the biodegradation is increasing due to the expensiveness of the chemicals. So bioremediation is the best choice. The effluents should be degraded from the environment because they are very dangerous and have a bad impact on human beings. These pollutants sink into the water and cause pollution. These pollutants are treated with the help of microbes in bioremediation process. It is the best method because it is cost effective and eco-friendly. Different techniques of bioremediation are used to convert toxic substances into less toxic substances.
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
In the present study we monitor the eff ect of copper-contaminated culture media on development and active compound biosynthesis of two Rhodotorula mucilaginosa strains, assigned as R1 and R2. The media was prepared in aqueous extracts of Asclepias syriaca stems and diff erent copper ions concentrations were added. The data reveals that the presence of 10 mg/ L Cu2+ for the Rhodotorula mucilaginosa strain-1 (R1) and 50 mg/ L Cu2+ for the Rhodotorula mucilaginosa strain-2 (R2) strain fermentation increases the biomass yield (24.7 g and 14.8 g wet biomass/ L culture medium, respectively) and biosynthesis of carotenoid pigments (approximately 1.4 μg/ g dry biomass) compared with references. The chelating properties of polyphenol compounds from aqueous extracts of Asclepias syriaca
stems was confi rmed by detection of 17.9 mg/ L Cu2+ in extracts with 100 mg/ L Cu2+ added, after 24 hours at 4°
C. In the residual culture media, we have determines that the Cu2+ concentrations decreased at 14.0 mg/L for Rhodotorula mucilaginosa strain-1 (R1) and 13.8 mg/
L for Rhodotorula mucilaginosa strain-2 (R2) strain fermentation, respectively, which means that the copper was trapped by the yeasts cells. Likewise, the polyphenols are digested and used as a carbon source. These results bring a significant contribution to the possibility of yeast fermentations in a low cost-vegetal polyphenol and copper ions system.
A Selective Study on Decolorization of Textile Azo Dye using Genetically Modi...BRNSS Publication Hub
Aim: Bioremediation of textile effluents using microorganisms can transfer toxic dyestuffs into non-toxic. Moreover, the discovery of the value of brown-rot fungi in bioremediation has brought a great success in this field. Molecular biology related to brown-rot fungi, especially related to the extraction of genetic material (RNA and DNA), gene cloning, and the construction of genetically engineered microorganisms is especially attractive and thus investigated in recent years. Steam-assisted dry gel conversion of tetraethyl orthosilicate and sodium aluminate to ZSM-5 and ZSM-5 activated carbon composite. Result: The resulting material exhibited hierarchical pore structure with high surface area and porosity as characterized by X-ray diffraction and nitrogen adsorption. The addition of activated carbon enhanced the surface area and adsorption percentage of aqueous lead (Pb2+) and cadmium (Cd2+) from aqueous solution and further from industrial effluents. Conclusion: The co-ordination of the alumina incorporated was analyzed using Al magic-angle spinning nuclear magnetic resonance. ZSM-5/activated carbon composite with high crystallinity was obtained which exhibited high adsorption rates when compared to ZSM-5, activated carbon individually, and their mechanical mixtures.
Isolation, Screening, and Characterization of Biosurfactant-Producing Microor...BRNSS Publication Hub
Introduction: Biosurfactants are amphiphatic in nature and are surface-active compounds produced by microorganisms. These molecules reduce interfacial surface tension between aqueous solutions and hydrocarbon mixtures. Unfortunately, oil spills and industrial discharges from petroleum-related industries have been identified as the major pollution sources. The hydrophobicity and low aqueous solubility of petroleum pollutant limit the biodegradation process. The features that make biosurfactants as an alternative to commercially synthesized surfactants are its low toxicity, higher biodegradability and, hence, greater environmental compatibility, better foaming properties, and stable activity at extreme pH, temperature, and salinity. Objective: Therefore, in this study, hydrocarbon-degrading bacteria were screened from petroleum-contaminated soil, characterized and optimization of the physical and nutrient parameters were done to enhance the production of biosurfactants. Results: Petroleum-contaminated soil was collected from different petrol pumps in Pune and screening was done on minimal salt medium media containing palm oil as carbon source using hemolytic activity, emulsification index, drop-collapse test, and oil displacement method. The most promising strain was isolated and identified using Bergey’s Manual of Determinative Biology and 16s rRNA sequencing and was found to be Staphylococcus epidermidis. The optimization of various parameters, namely temperature, pH, carbon, and nitrogen sources on growth, and biosurfactant production was studied. The highest biosurfactant production was obtained when MSS media contains sucrose (carbon source) and urea (nitrogen source) at pH 10 and temperature 55°C. The Fourier transform-infrared (FT-IR) analysis of purified biosurfactant indicated the presence of lipopeptide biosurfactant when compared with reference FT-IR spectra.
Chemical and Microbial Reactions Occurring during VermicompostingYogeshIJTSRD
Vermicomposting is a unique process that occurs in earthworms gut to convert organic wastes into organic fertilizer or vermicompost by using joint action of earthworms and microorganisms. Organic wastes used were the mixture of spent mushrooms waste, coconut husks, cow dung, vegetables residue, and leaf litter. Locally available earthworms are also used for vermicomposting but their mode of feeding is very slow and the earthworm which lives below the soil is also not suitable for vermicompost production. The Red worms Eisenia foetida and African earthworm Eudrillus engenae are promising worms used for vermicompost production. All the two worms can be mixed together for vermicompost production. In the composting process, egg shells flour and fish meal are added into the vermicompost as additives materials. The results indicate that the combined vermicomposting and composting process with addition the additives materials improves the chemical composition of vermicompost compared to using vermicomposting process alone. The percentage of nitrogen, phosphorous, potassium, calcium and magnesium in vermicompost was found to increase while C N ratio, pH and total organic carbon declined as a function of the vermicomposting. Dr. Atul Kumar Sharma | Dr. Kamlesh Rawat "Chemical and Microbial Reactions Occurring during Vermicomposting" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd45029.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/45029/chemical-and-microbial-reactions-occurring-during-vermicomposting/dr-atul-kumar-sharma
Screening of Biosurfactant Bioemulsifier Producing Bacteria from Petroleum Co...ijtsrd
The release of impurities in the environment, containing petroleum and petroleum cogitated products, is engenders of global being taint. It is also a hazardous for human and animal health, since many of these impurities have evidenced to be toxic and oncogenic. Hydrocarbon particles that are secreted into the environment are hard to get rid of, since they change state to surfaces and are captured by surface tension in a water immiscible stage. Bioremediation has tested to be an alternate to lessen the effects caused to impureness of soil and water, applying the metabolic abilities of microorganisms that can apply hydrocarbons as source of carbon and energy, or that can alter them by co metabolism. The proficiency of removal is directly related to the compound’s chemical structure, to its bioavailability deliberation, harmfulness, flexibility and approach and to the physicochemical situation present in the atmosphere. Perwez Qureshi | Dr. Reshma Jaweria "Screening of Biosurfactant/Bioemulsifier Producing Bacteria from Petroleum Contaminated Soil" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd46276.pdf Paper URL: https://www.ijtsrd.com/biological-science/microbiology/46276/screening-of-biosurfactantbioemulsifier-producing-bacteria-from-petroleum-contaminated-soil/perwez-qureshi
Poly-훽-hydroxybutyrate degradation by Aspergillus fumigates isolated from soi...IOSRJPBS
Poly-β-hydroxybutyrate acid (PHB) is thermoplastic biopolymers, synthesized by some bacterial genera under stress conditions. The degradation of PHB was detected in Petri dish by formation of a clear zone around the fungal colonies due to production of depolymerase enzyme which has interesting role in PHB degradation process. The most active PHB degrader fungi was selected and identified as Aspergillus fumigates using morphological characters. The highest PHB degradation in Petri dish by A. fumigates was at pH 5, 30ᵒC and 7days. In liquid medium, degradation by A. fumigates was studied using enzyme assay method (U/ml). All the experiments were performed enzyme activities were monitored. After 3 days of incubation, maximum PHB depolymerase production was at pH 5 and 30°C. In conclusion, PHB can be degraded in solid and liquid medium using fungal depolymerase enzyme.
Isolation and Screening of Hydrogen Producing Bacterial Strain from Sugarcane...Editor IJCATR
The aim of this study is to isolate a highly competent bacterium with potent cellulose degrading capability and a better
hydrogen producer. Soil sample from sugarcane bagasse yard was isolated, serially diluted and plated on cellulose specific nutrient
agar plate. Four colonies have been isolated in which a single colony has potent cellulose degrading ability and the highest hydrogen
productivity of 275.13 mL H2 L-1. The newly isolated bacterium was morphologically and biochemically characterized. The
molecular characterization of the bacterium was carried out using 16S rDNA sequencing and the organism was identified as
Bacilllus subtilis AuChE413. Proteomic analysis such as MALDI-TOF was carried out to differentiate the isolated Bacillus subtilis
from Bacillus thuringiensis and Bacillus amyloliquefaciens. Phylogenetic tree was constructed to analyze the evolutionary
relationship among different genus and species with the newly isolated strain.
Chemical conversion of a substance mediated by living organisms or enzymes
Can result in DETOXIFICATION and BIOACTIVATION
Vital to survive
Key in defense mechanism
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
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Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
A Strategic Approach: GenAI in EducationPeter Windle
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This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
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2. Bioremediation is the use of micro-organisms- naturally present
or genetically engineered to remove pollutants.
They can be applied on site (in situ) or off site ( ex situ) mediated by
mixed microbial consortia or pure microbial strains and plants.
They include several processes – bioventing, biostimulation,
biosparging, bioaugmentation, bioleaching, phytoremediation,
fungal bioremediation and biosorption.
3.
4. Mycoremediation, a phrase coined by Paul Stamets, is a form of bioremediation, using fungi to
degrade or sequester contaminants in the environment.
5. They are capable of mineralizing a wide variety of toxic xenobiotics.
They occur ubiquitously in the natural environment.
They have the potential to oxidize substrates that have low solubility because the
key enzymes involved in the oxidation of several pollutants are extracellular.
The constitutive nature of the key enzymes involved in lignin degradation obviates
the need for these organisms to be adapted to the chemical being degraded.
The preferred substrates for the growth of white-rot fungi, such as corn cobs, straw,
peanut shells, and sawdust, are inexpensive and easily added as nutrients to the
contaminated site.
The key LDEs are expressed under nutrient-deficient conditions, which are
prevalent in many soils. Nitrogen serves as the main limiting factor.
Four main genera of white rot fungi have shown potential for bioremediation:
Phanerochaete, Trametes, Bjerkandera, and Pleurotus.
6. Lignin peroxidase is a glycosylated heme protein that catalyzes
hydrogen peroxide-dependent oxidation of lignin-related aromatic
compounds. They have a higher redox potential than most peroxidases
and so are able to oxidize a wide range of chemicals, including some
non-phenolic aromatic compounds.
Mn-dependent peroxidase also requires hydrogen peroxide to oxidize
Mn2+ to Mn3+. The Mn3+ state of the enzyme then mediates the
oxidation of phenolic substrates.
Laccase, a multicopper oxidase enzyme, is the primary enzyme
involved in the degradation process. It uses dioxygen as an oxidant,
reducing it to water and it has the ability to catalyze the oxidation of a
widerange of dihydroxy and diamino aromatic compounds. It is most
stable at a pH of 5-6 and temperature of 45°C. However, this enzyme is
still active at pH levels as low as 4 and as high as 7. This is beneficial
in contaminated field sites with very low pH levels.
7.
8.
9. SOURCES - Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated
dibenzo-furans (PCDFs) are unintentionally formed in the process of:
- producing chlorine-containing herbicides,
- in the bleaching of paper pulp by using chlorine compounds
- during combustion of domestic and industrial waste
- during burning of petrochemicals and PAHs.
EFFECTS –
- PCDDs and PCDFs have been a public concern for several decades because of
their strong toxicity in animal tests. These hazardous compounds tend to
accumulate in the body fat of animals since they are relatively lipophilic and
chemically stable.
- They have been released into the environment as recalcitrant contaminants and
have been found in many environmental matrices such as air, soil, and plants.
- Studies of the degradation of PCDDs and PCDFs in the environment have shown
these rates to be extremely low, the half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin
(2,3,7,8-tetraCDD) in an outdoor pond and soil being in the order of 1 year.
10. BIODEGRADATION METHODS –
P. sordida YK-624 and P. chrysosporium IFO31249 culture were prepared on
Low-nitrogen basal III medium containing 1% glucose, 1.2 mM ammonium
tartrate, and 20 mM dimethylsuccinate (pH 4.5). After incubation for 7 days, 10%
glucose was added to each inoculated flask and the headspaces were flushed with
oxygen.
Ethyl acetate solution of PCDDs-PCDFs (500 pg each) was added, and each flask
was sealed with a glass stopper and sealing tape. The cultures were incubated for 3,
7, 10, and 14 days (each in triplicate). For 10- and 14-day incubation samples, 10%
glucose was added to the cultures, and the flasks were oxygenated on day 7.
At the end of the incubation, hexane and 13C-labeled PCDDs-PCDFs (500 pg each)
was added to the cultures. To recover the PCDDs and PCDFs adsorbed to the
mycelia and to dissolve the mycelia thoroughly, concentrated sulphuric acid was
added.
11. The cultures were extracted twice with hexane. All of the hexane extracts
were washed with water.
The hexane layer was evaporated, and polar compounds were removed
with silica gel chromatography.
Uninoculated medium controls were treated in the way.
Concentrations of PCDDs-PCDFs were determined by high-resolution gas
chromatography and high-resolution mass spectrometry (HRGC-HRMS)
(selected ion-monitoring mode [SIM]).
12. RESULTS –
For all compounds, the glucose-supplemented culture led to a higher
percent degradation.
13. In both PCDDs and PCDFs, hexa-CDD and -CDF showed the highest
degradation values, i.e., ;75% and ;70%, respectively.
The degradation of PCDDs-PCDFs by P. Chrysosporium IFO31249 was
also carried out for 14 days under conditions similar to those for YK-624
(Table 1). The results show almost the same degradation rate as that for
YK-624.
Time courses for the degradation of PCDDs and PCDFs by the fungus
YK-624 were plotted. All of the PCDDs and PCDFs were partially
degraded. The percent degradation values were promoted by the addition
of glucose and oxygenation on days 0 and 7; however, the effect
continued only for 3 days, as indicated by the fact that the slopes of
percent degradation of days 0 to 3 and 7 to 10 were steeper than those of
days 3 to 7 and 10 to 14 – (figure 4 and 5).
14. Degradation of PCDDs by P. sordida YK-624 under low-nitrogen
medium. Glucose was added to each culture, and headspaces were purged with
oxygen.
15. Degradation of PCDFs by P. sordida YK-624 under low-nitrogen
Medium. Glucose was added to each culture, and headspaces were purged with
oxygen.
16. CONCLUSION –
The degradation method was developed carefully to avoid the evaporation
of dioxins and consequent human exposure. The solubilities of PCDDs are
extremely low. The 500 pg of these compounds used in this experiment did
not dissolve in 10 ml of the aqueous culture and remained largely in solid
or vapour states. Consequently, biodegradation was carried out in flasks by
sealing with glass stoppers and, in addition, sealing with sealing tape in
order to protect against the loss of these compounds.
P. sordida YK-624 and P. chrysosporium IFO31249 were capable of
substantial degradation of the mixtures of the 2,3,7,8-substituted tetra- to
octa-CDDs and CDFs tested, as determined by substrate disappearances.
These fungi showed no clear structural dependence for degradation of
PCDDs and PCDFs, verifying that the degradation of these substrates is
indeed, a free-radical process showing little specificity.