Chemical Composition and Thermal Behavior of Kraft LigninsMichal Jablonsky
Lignin has great potential for utilization as a green raw material or as an additive in various industrial applications, such as energy, valuable chemicals, or cost-effective materials. In this study, we assessed a commercial form of lignin isolated using LignoBoost technology (LB lignin) as well as three other types of lignin (two samples of non-wood lignins and one hardwood kraft lignin) isolated from the waste liquors produced during the pulping process. Measurements were taken for elemental analysis, methoxyl and ash content, higher heating values, thermogravimetric analysis, and molecular weight determination. We found that the elemental composition of the isolated lignins affected their thermal stability, activation energies, and higher heating values. The lignin samples examined showed varying amounts of functional groups, inorganic component compositions, and molecular weight distributions. Mean activation energies ranged from 93 to 281 kJ/mol. Lignins with bimodal molecular weight distribution were thermally decomposed in two stages, whereas the LB lignin showing a unimodal molecular weight distribution was decomposed in a single thermal stage. Based on its thermal properties, the LB lignin may find direct applications in biocomposites where a higher thermal resistance is required.
Chemical Composition and Thermal Behavior of Kraft LigninsMichal Jablonsky
Lignin has great potential for utilization as a green raw material or as an additive in various industrial applications, such as energy, valuable chemicals, or cost-effective materials. In this study, we assessed a commercial form of lignin isolated using LignoBoost technology (LB lignin) as well as three other types of lignin (two samples of non-wood lignins and one hardwood kraft lignin) isolated from the waste liquors produced during the pulping process. Measurements were taken for elemental analysis, methoxyl and ash content, higher heating values, thermogravimetric analysis, and molecular weight determination. We found that the elemental composition of the isolated lignins affected their thermal stability, activation energies, and higher heating values. The lignin samples examined showed varying amounts of functional groups, inorganic component compositions, and molecular weight distributions. Mean activation energies ranged from 93 to 281 kJ/mol. Lignins with bimodal molecular weight distribution were thermally decomposed in two stages, whereas the LB lignin showing a unimodal molecular weight distribution was decomposed in a single thermal stage. Based on its thermal properties, the LB lignin may find direct applications in biocomposites where a higher thermal resistance is required.
Applications of polymers in everyday lifeIshaneeSharma
This pdf file is about applications of polymer in daily life. This pdf covers the applications of polymer in agriculture, sports, household and medical industry.
Introduction
Types
Characteristics of Biopolymer
Applications
Conclusion
References
Biopolymers are polymers produced from natural sources either
chemically synthesized from a biological material or entirely
biosynthesized by living organisms.
Plastics are light weighted, durable, corrosion resistant materials, strong, and inexpensive. Scientists have reported many adverse effects of the plastic in the environment and human health. Nowadays biodegradable plastics are considered as the environmental friendly. The plastic polymers as such at room temperatures are not considered as toxic. The toxic properties are found in plastics, when heat is released from the food material in which they are covered and then they produce serious human health problems. This review articles covers the list of biodegradation of plastics, some factors that affect their biodegradability, plastic types and their application and plastic degrading by fungi are discussed. Kannahi M | Thamizhmarai T"Biodegradation of Plastic by AspergillusSP" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, URL: http://www.ijtsrd.com/papers/ijtsrd7026.pdf http://www.ijtsrd.com/biological-science/microbiology/7026/biodegradation-of-plastic-by-aspergillussp/kannahi-m
Degradation of Low Density Polyethylene Due To Successive Exposure to Acid Ra...Editor IJCATR
Utilization of polymer products for outdoor applications is continuously increasing. So the stability of polymers against
environmental degradation became top of interests for many researchers. The effect of environmental elements on the polymers stability
has been studied, but individually. A solution against an environmental element may conflict with a solution against other element.
Therefore current study aimed to clarify a sort of these conflicts, by successive exposure of low density polyethylene (LDPE) films to
acid rains and ultra violet (UV) radiation for different times. The used LDPE films are selected from the commercial grads which are
used for plants greenhouses, in order to use samples fully protected against environmental elements. It is found that acid rains etch PE
films, causing removal for some of the UV stabilizer additives, and hence UV radiation could attack PE films seriously causing remarked
oxidative degradation. This study includes wide comparisons between effects of acid rain only, UV irradiation only, acid rain followed
by UV irradiation and UV irradiation followed by acid rain exposure. Variations in the chemical composition, morphological structures,
thermal and mechanical properties are detected by the IR- spectroscopy, X-ray diffraction, differential thermal analysis (DTA) and
tensile tests. A new view for the differentiation between degradations caused by acid rains and UV radiation is discussed. Lot of
experimental data are given in many coloured graphs and tables
microbial degradation of plastics can aid in the reduction of environmental plastic pollution along with plastic waste management. Rigorous research is required in order to discover new microbial strains that can potentially degrade plastics. A few microbes have been discovered that can degrade the plastic over time but there is a need for gene editing and enhancement to increase their potential of degradation.
This presentation deals with the usage of Nanocomposites in food packaging and different types of Nanocomposites used for coating to manufacturing of films.
Applications of polymers in everyday lifeIshaneeSharma
This pdf file is about applications of polymer in daily life. This pdf covers the applications of polymer in agriculture, sports, household and medical industry.
Introduction
Types
Characteristics of Biopolymer
Applications
Conclusion
References
Biopolymers are polymers produced from natural sources either
chemically synthesized from a biological material or entirely
biosynthesized by living organisms.
Plastics are light weighted, durable, corrosion resistant materials, strong, and inexpensive. Scientists have reported many adverse effects of the plastic in the environment and human health. Nowadays biodegradable plastics are considered as the environmental friendly. The plastic polymers as such at room temperatures are not considered as toxic. The toxic properties are found in plastics, when heat is released from the food material in which they are covered and then they produce serious human health problems. This review articles covers the list of biodegradation of plastics, some factors that affect their biodegradability, plastic types and their application and plastic degrading by fungi are discussed. Kannahi M | Thamizhmarai T"Biodegradation of Plastic by AspergillusSP" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, URL: http://www.ijtsrd.com/papers/ijtsrd7026.pdf http://www.ijtsrd.com/biological-science/microbiology/7026/biodegradation-of-plastic-by-aspergillussp/kannahi-m
Degradation of Low Density Polyethylene Due To Successive Exposure to Acid Ra...Editor IJCATR
Utilization of polymer products for outdoor applications is continuously increasing. So the stability of polymers against
environmental degradation became top of interests for many researchers. The effect of environmental elements on the polymers stability
has been studied, but individually. A solution against an environmental element may conflict with a solution against other element.
Therefore current study aimed to clarify a sort of these conflicts, by successive exposure of low density polyethylene (LDPE) films to
acid rains and ultra violet (UV) radiation for different times. The used LDPE films are selected from the commercial grads which are
used for plants greenhouses, in order to use samples fully protected against environmental elements. It is found that acid rains etch PE
films, causing removal for some of the UV stabilizer additives, and hence UV radiation could attack PE films seriously causing remarked
oxidative degradation. This study includes wide comparisons between effects of acid rain only, UV irradiation only, acid rain followed
by UV irradiation and UV irradiation followed by acid rain exposure. Variations in the chemical composition, morphological structures,
thermal and mechanical properties are detected by the IR- spectroscopy, X-ray diffraction, differential thermal analysis (DTA) and
tensile tests. A new view for the differentiation between degradations caused by acid rains and UV radiation is discussed. Lot of
experimental data are given in many coloured graphs and tables
microbial degradation of plastics can aid in the reduction of environmental plastic pollution along with plastic waste management. Rigorous research is required in order to discover new microbial strains that can potentially degrade plastics. A few microbes have been discovered that can degrade the plastic over time but there is a need for gene editing and enhancement to increase their potential of degradation.
This presentation deals with the usage of Nanocomposites in food packaging and different types of Nanocomposites used for coating to manufacturing of films.
Aqueous solutions of ionic liquids in the
extraction and purification of
compounds from biomass, João A. P. Coutinho, CICECO, Department of Chemistry
ACel Programme Seminar June 5, 2015
http://fibic.fi/events/acel-program-seminar-jun-5-cellulose-reactivity-and-recycling-of-ionic-liquids
Ionic Liquid Pretreatment
DISCLAIMER:
YOU AGREE TO INDEMNIFY BioRefineryEPC™ , AND ITS AFFILIATES, OFFICERS, AGENTS, AND EMPLOYEES AGAINST ANY CLAIM OR DEMAND, INCLUDING REASONABLE ATTORNEYS' FEES, RELATED TO YOUR USE, RELIANCE, OR ADOPTION OF THE DATA FOR ANY PURPOSE WHATSOEVER. THE DATA ARE PROVIDED BY BioRefineryEPC™ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY DISCLAIMED. IN NO EVENT SHALL BioRefineryEPC™ BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM ANY ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE DATA.
Ionic Liquids : Green solvents for the futureMrudang Thakor
Ionic Liquids are entirely made up of Ions also known as Room Temperature Ionic Liquids (RTILs).
They are in demand because of their unmatchable uses and applications in the field of chemistry.
Wood and Bamboo Fiber Combination in the Production of Poly Lactic Acid (PLA)...IOSR Journals
Bio-composite made from a combination of natural fibers such as wood fiber (wood hard or soft) or other fibers (fiber grain, flax, sisal and hemp) in a polymer matrix. In this study, natural fibers such as cellulose synthesized from Meranti wood (KM) and Betung bamboo (BB) as a matrix or reinforcement material poly lactic acid (PLA) are biodegradable. Tensile and flexible strength tests carried out using Universal Testing Machine (UTM). Flexible and tensile tests that bio composite Betung bamboo better than Meranti wood. Apparently the flexion strength of the composite KM between 10% and 20% there was no significant difference, In contrast to the composition of the bio composite between 10% and 20%. Flexion strength has height values contained in the bio composite Betung Bamboo 20% of 57.4054 N/mm2. The highest power of elasticity found in the composition of the bio composite Betung bamboo 20% of 1.95 GPA. Betung bamboo is high strength reinforced silica matrix composite.
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.
Development of sawdust from the Lagos Lagoon in Nigeria as a renewable feedst...Innspub Net
The accumulation of solid waste and consumption of fossil fuels are two phenomenons which already have a major destructive effect on the environment. The lack of alternative solid waste management procedures and shortage of the development of renewable energy resources should be addressed in order to sustain environmental quality. Sawdust is a major waste product along the Lagos lagoon with cellulose one of the predominant structural components of sawdust. The bio-conversion of waste cellulose, a glucose biopolymer into glucose a fermentable sugar has been performed with cellulase from Aspergillus Niger. Delignified and non-delignified sawdust from five different trees along the Lagos Lagoon have been saccharified with A. niger cellulase. The saccharification of these sawdust materials have been performed at different incubation temperatures of 30°C, 40°C, 50°C and 60°C. Optimum saccharification of non-delignified and delignified cellulose from the various trees along the Lagos Lagoon were optimum saccharified at different temperatures resulting in different sugar concentrations produced. A temperature of 40°C was optimum for maximum degradation of non-delignified cellulose from all the trees producing sugar at concentration between 3.0 – 4.3mg.ml-1. Optimum saccharification of delignified cellulose from all the trees was obtained at a temperature of 50°C resulting in a sugar concentration of 5.9 – 8.4mg.ml-1.
Mechanical Characterization of Biodegradable Linen Fiber CompositesIJMER
Abstract: The conventional materials like iron, mild steel, cast iron etc are having good mechanical properties. Hence they are widely used in structural engineering applications. These conventional materials have some defects like formation of rust, low weight to strength ratio, high production cost. To overcome these defects, engineers started fabricating composite materials. Composites exhibit peculiar properties like different strengths in different directions, rust resistant, high strength to weight ratio, but they pollute the environment. Now the natural fibre composites are widely used in automobile industry. The natural fibres and resins are used to fabricate an eco friendly composite material. Lack of resources and increasing environmental pollution has evoked great interest in the research of materials that are
friendly to our health and environment. Bio polymer composites fabricated from natural fibres is currently
the most promising area in polymer sciences. This is designed to assess the possibility of fibre as reinforcing material in composites. Epoxy resin was made a stiffened panel to conduct tensile test. In this paper it is aimed to explain all possible ways to use natural composites in automobile components. The main advantages of using natural fibers are their degradability and light weight. They are environment friendly and also increase the fuel economy
Mechanical Characterization of Biodegradable Linen Fiber CompositesIJMER
The conventional materials like iron, mild steel, cast iron etc are having good mechanical properties. Hence they are widely used in structural engineering applications. These conventional materials have some defects like formation of rust, low weight to strength ratio, high production cost. To
overcome these defects, engineers started fabricating composite materials. Composites exhibit peculiar
properties like different strengths in different directions, rust resistant, high strength to weight ratio, but
they pollute the environment. Now the natural fibre composites are widely used in automobile industry.
The natural fibres and resins are used to fabricate an eco friendly composite material. Lack of resources
and increasing environmental pollution has evoked great interest in the research of materials that are
friendly to our health and environment. Bio polymer composites fabricated from natural fibres is currently
the most promising area in polymer sciences. This is designed to assess the possibility of fibre as
reinforcing material in composites. Epoxy resin was made a stiffened panel to conduct tensile test. In this
paper it is aimed to explain all possible ways to use natural composites in automobile components. The
main advantages of using natural fibers are their degradability and light weight. They are environment
friendly and also increase the fuel economy
Comparative Alterations in the Compositional Profile of Selected Root and Veg...IJEAB
Lignocellulosic feedstocks have gained worldwide interest as alternative biofuel source in the context of squeezing petroleum resources, enhanced environmental pollution from greenhouse gases and resulting climate change. The potential of agricultural processing residues such as root and vegetable peels (beet root, greater yam, pumpkin and vegetable banana) for bioethanol production was investigated through an understanding of their compositional profile and efficacy of three pretreatments in altering their composition and reducing biomass recalcitrance. Starch was the major polysaccharide in the residues (range: 25-37%), followed by cellulose (18-22%) and hemicellulose (15-20%). While dilute sulfuric acid (DSA; 121°C ; 0.102 MPa) hydrolyzed starch and hemicellulose to a high extent, steam pretreatment of moist residues (40 % and 50 % MC) at 100 °C also facilitated hemicellulose and starch solubilization. On the contrary, lime pretreatment retained most of the cellulose, hemicellulose and starch in the pretreated residues. Delignification was the highest (28- 37%) in steam pretreated residues, with minimal effect in DSA and lime pretreatments, necessitating lignin binding surfactants during saccharification in the latter. Reducing sugar content in pretreated liquors and Pretreatment Efficiency (%) were the highest (40-45 g L-1 and 57-64% respectively) in the DSA pretreatment. The study showed that as the pretreated liquor DSA and steam pretreatment was rich in fermentable sugars, whole slurry saccharification would be beneficial for maximizing the bioethanol yield.
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.
Effect of Chemical Treatment and Curing Parameters on Mechanical Properties o...IJERA Editor
A brief overview on natural fiber reinforced polymer composites is presented in this work. There is a growing trend to use non conventional and environmental friendly resources for engineering applications. In this scenario Natural fiber are offering a wide range of possibilities. Detailed and thorough study of structure of natural fiber indicates about its hydrophilic nature. Various types of chemical treatment techniques are used by researchers to increase the affinity of reinforcement and matrix .Studies shows that different factors like curing time, temperature, loading condition, fiber orientation etc. affect the properties of natural fiber composites. Lot of work has been carried out with the combination of different fibers and different polymers. Comparative data is presented on properties of different composite.
Similar to Improved biological delignification of wood biomass via ionic liquids pretreatment (20)
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
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The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
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All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
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We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
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Neuro-symbolic is not enough, we need neuro-*semantic*
Improved biological delignification of wood biomass via ionic liquids pretreatment
1. Journal of Energy Technologies and Policy
www.iiste.org
ISSN 2224-3232 (Paper) ISSN 2225-0573 (Online)
Vol.3, No.11, 2013 – Special Issue for International Conference on Energy, Environment and Sustainable Economy (EESE 2013)
Improved biological delignification of wood biomass via Ionic
liquids pretreatment: A one step process
Muhammad Moniruzzaman, 1* Tsutomu Ono, 2 Suzana Yusup,3 Sujon Chowdhury, 1 Mohammad Azmi Bustam, 1
Yoshimistu Uemura3
1. Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, MALAYSIA
2. Department of Applied Chemistry, Graduate School of Natural Science and Technology,
Okayama University, 3-1-1 Tsushima, Okayama 700-8530, JAPAN
3. Biomass Processing Lab, Center for Biofuel and Biochemical Research, Department of Chemical Engineering,
Universiti Teknologi PETRONAS, 31750 Tronoh, MALAYSIA
*Email address of corresponding author: m.moniruzzaman@petronas.com.my
Abstract
The enzymatic pretreatment of wood biomass for degrading lignin, a complex aromatic polymer, has received
much attention as an environmentally safe or “green” process. However, this process for lignin degradation has
been found to be very slow, even needed several months. To overcome this limitation, this study reports a new
approach for enhanced enzymatic delignification of wood biomass using room temperature ionic liquids
(RTILs)- a potentially attractive “green” and “designer” solvent- as (co)solvents or/and pretreated agents. The
method comprised pretreatment of wood biomass prior to enzymatic delignification in ILs-aqueous systems with
the aim of overcoming low delignification efficiency associated with the difficulties in enzyme accessibility to
the solid substrate and the poor substrate and products solubility in aqueous system. The results showed that IL
[emim] [OAc] (1-ethyl-3-methylimidazolium acetate) was better solvent for wood delignification than IL
[bmim][Cl] (1-butyl-3-methylimidazolium chloride). The recovered cellulose rich materials obtained from
combination effects of IL and biological pretreatment contained significantly lower amounts of lignin as
compared to the amounts found when each method applied alone. The produced cellulose rich materials were
characterized by acid hydrolysis, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy
(SEM), and X-ray diffractometry (XRD). SEM and XRD revealed considerable microstructural and crystallinity
index changes in the pretreated cellulose rich materials. We believe that this newly developed process will play
a great role in converting cellulosic biomass- the most abundant renewable biomaterials in the world- to
biomaterials, biopolymers, biofuels, bioplastics and hydrocarbons.
Keywords: ionic liquids, wood biomass, cellulose, lignin, laccase, enzymatic delignification.
1. Introduction
The rapidly growing demand for energy, uncertainty about the costs and supply of petroleum and concerns about
environmental impact by the use of petroleum based resources have led to motivated interest in alternative
resources, particularly from renewable resources including lignicellulosic biomass. Considering these facts, the
use of lignocellulosic based materials in various sectors (e.g., automotive and aerospace) over petro- materials
has received increased attentions due to the growing global environmental awareness and concepts of
sustainability and industrial ecology and no conflict between food vs materials. Wood – the most abundant
lignocellulosic resources on the world – consists of up to 50% cellulose that is rigid semi-crystalline embedded
in amorphous hemicelluloses and lignin. Cellulose and lignin –Earth’s most and second most abundant
biopolymer, respectively– represent an enormous carbon-neutral renewable resource for biomaterials and
bioenergy production. This is why, the sepapartion of such components from wood biomass has gained a great
deal of recent interest. However, the recalcitrant nature of the wood cell wall represents the biggest challenge in
the development of wood biomass to biomaterials/ biocomposites technologies. In fact, a distinct crystalline
structure of cellulose makes it a challenge to find suitable solvents for its dissolution as well as isolation from
lignin. To date, a number of pretreatment approaches including physical (e.g., pyrolysis and mechanical
disruption)(Moiser et al., 2005), physico-chemical (e.g., steam explosion and ammonia fiber explosion
( Hendricks & Zeerman, 2009), chemical (e.g., acid hydrolysis, alkaline hydrolysis and oxidative delignification)
( Merino et al., 2007), and biological methods (Lee, 1997; Bak et al., 2009) have been investigated to delignify
wood biomass for extraction of cellulose. Many of these methods require high temperatures and pressures, as
well as highly concentrated chemicals, for the cooking process. Conventional chemicals, such as sulfates, and
144
EESE-2013 is organised by International Society for Commerce, Industry & Engineering.
2. Journal of Energy Technologies and Policy
www.iiste.org
ISSN 2224-3232 (Paper) ISSN 2225-0573 (Online)
Vol.3, No.11, 2013 – Special Issue for International Conference on Energy, Environment and Sustainable Economy (EESE 2013)
sulfite pulping processes pose serious environmental hazards in air and water. Moreover, high temperature based
cooking processes result in the production of inhibitory chemicals and degradation products. On the other hand,
the biological pretreatment for wood delignification is an environmentally safe. Generally, enzymes isolated
from naturally occurring fungi, or with enzymes produced by genetically engineered fungi have been used for
wood biodegradation. However, this approach in aqueous system has been found to be very slow mainly due to
the difficulties in enzyme accessibility to the solid substrate and the poor solubility of lignin (Martinez et al.,
2009). It is therefore desirable to develop a biomass pretreatment process that is not only the environmentally
friendly but also efficient and cost effective for biomass conversion to cellulose and lignin.
The poor solubility of substrate and products during wood delignification in aqueous systems can be overcome
by using ionic liquids (ILs) as cosolvents. It is well recognized that ILs, a potentially attractive “green”
recyclable alternative to environmentally harmful organic solvents, have been increasingly exploited as solvents
and/or (co)solvents and/or reagents in a wide range of applications including pretreatment of lingo-cellulosic
biomass (Kilpelainen et al., 2007; Mora-pale et al., 2011; Sun et al., 2009). The very high solvating properties of
ILs have been exploited in the dissolution of cellulose (Swatloski et al., 2002), lignin (Pu, 2007) and wood (Sun
et al., 2011). Generally, hydrophilic ILs are able to completely solubilize wood at over 100 ºC, and cellulose rich
materials can readily be precipitated with an anti-solvent, such as acetone and ethanol. The degree of
polymerization (DP) of regenerated cellulose was found to be reduced notably which lead to enhanced enzymatic
cellulose hydrolysis, making the system suitable for biomass to biofuels technologies (Lee et al., 2009). However,
the production of high strength biomaterials and biocomposites requires structurally strong cellulose fibers. It
is worthy to mention that less attention was paid on designing and development of IL-based technology which
can extract cellulose with minimum altered structure from wood.
Unfortunately, the practical obstacle of using ILs for enzymatic delignification is that many ILs, particularly
hydrophilic ones have negative effect on enzyme structure, resulting in deactivation of enzyme (Moniruzzaman
et al., 2008, 2009, 2010a, 2010b). Such effects could be balanced with the increase the solubility of substrates
and products leading to better performances in terms of enhanced yield. Recently, it was reported that laccases
can maintain their activity for the oxidation of 2, 2′-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) and
catechol in ILs-water systems containing over 80% of water (Shipovskov et al., 2008;Tavares et al., 2008). This
is consistent what was reported for the performances of others enzymes in IL alone or IL-water systems
(Moniruzzaman et al., 2010 a).
To this end, recently, it was found that enzymatic delignification efficiency can be improved by IL pretreatment
of wood biomass prior to enzymatic delignification in aqueous systems in the presence of small amount of water
(Moniruzzaman & Ono, 2012). In this one step process, 10 wt% wood chips in an IL were cooked and then
aqueous solution containing enzyme was added directly to start the delignification. Preliminary results indicated
that enzymatic delignification efficiency of IL-swollen wood biomass became higher than that of untreated
materials. In fact, wood biomass is swollen by ILs prior to delignification provided increased surface area
accessible to the enzymes. The system has a significant advantage because the substrate and product solubility
are expected to increase in ILs which may enhance the process efficiency. This notble finding inspires us to
investigate how the major process parameters such as type of ILs and cooking time affect delignification. We
believe that delignification efficiency will be improved to a extent after optimization such parameters.
Here, the objective of this study is to comduct enzymatic delignification of wood biomass pretreated with ILs
using laccase as a biocatalyst. The goal of pretreatment is to with the aim of overcoming low delignification
efficiency associated with the difficulties in enzyme accessibility to the solid substrate and the poor substrate and
products solubility in aqueous system.The effect of the major parameters including types of ILs and incubation
time in ILs were investigated. The treated wood fibers were characterized using Fourier-transform infrared
spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffractometry (XRD) and compared
those with untreated wood fibers. Commercial laccase which is a copper-containing oxidase enzyme obtained
from white rot fungi, was selected as a biocatalyst because it can degrade the lignin of biomass leaving the other
components (e.g., cellulose) virtually untouched (Blanchette, 1991).
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2. Materials and method
2.1 Materials
Wood chips from hinoki cypress (Chamaecyparis obtusa) were received from Okayama Biomass Center, Japan.
Alkali lignin and 1-Hydroxybenzotriazole (HBT) were purchased from Aldrich Chemical Co. (St. Louis, MO).
The IL [emim][OAc](1-ethyl-3-methylimidazolium) (≥ 95%) and IL [bmim][Cl] (1-butyl-3- methylimidazolium
chloride) were obtained from Ionic Liquids Technologies GmbH (Heilbronn,Germany) and used as received.
2,20-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) (98%) was obtained from
Sigma (St. Louis, MO). Commercial Laccase Y120 (EC. 1.10.3.2) (1000U/g) from Trametes sp. was kindly
supplied by Amano Enzyme Inc. (Nagoya, Japan).
2.1 Process
A simplified overview of experimental method was shown in Figure 1. Firstly, wood chips were grounded into
powders through a lab-scale roller mill and passed through sieves to separate fractions with 110–550 µm particle
sizes which were dried overnight in an oven at 110 °C. In a typically experiment, 200 mg of wood were added to
2 g IL in a three neck flask and heated at 80 °C in an oil bath with magnetic stirring for desired time. After
cooling the wood–IL mixture to room temperature, acetate buffer (100 mM, pH 4.5) containing laccase were
added to the flask, whereas 1-hydroxybenzotriazole (HBT) (1.5 wt% of wood chips) was added as a mediator.
Reaction was carried out with the supply of O2 bubbles with a small stirrer bar at 50 °C. After cooling the
reaction mixture to room temperature, 0.1 M NaOH was used to wash ILs and lignin away from the cellulosic
fibers. To remove traces of NaOH, the fibers were washed with distilled water until pH paper showing the final
drops of washing liquid to be pH neutral. The lignin content in the filtrate NaOH solution was determined by
measuring absorbance at 280 nm (Kilpelainen et al., 2007). Alkali lignin from Aldrich Inc. was used to prepare
the calibration curve (see Figure 2). After drying the treated wood fibers in a convection oven at 65 °C for 48 h,
sample was weighted and stored at vacuum desiccator. The recovery of IL for further use was carried out as
described previously (Tan et al., 2009). The content of untreated wood was determined using TAPPI methods
with a scaled down process.
2.2 Enzyme assay
Laccase activity was determined by oxidation of 2-2’.azmobis-(3.ethyl benzthiazoline-6-sulphonate) (ABTS).
The reaction mixture contained 0.5 mM ABTS, 0.1 M sodium acetate buffer, pH 5.0, and a suitable amount
of enzyme. Oxidation of ABTS was followed by absorbance increase at 420 nm (ε420 = 3.6 x 104 M-1 cm-1).
One unit was defined as the amount of enzyme that oxidized 1 µmol of ABTS per min and the activities were
expressed in U/gm.
Ionic Liquids Recycle
Particle Size
Reduction
Swollen in
Ionic Liquids
Biological
Pretreatment
Enzyme in buffer
Enzyme mediator
O2
Lignin
Wash and
Filtration
Cellulose Rich
Materials
Characterization
with Various
Methods
Figure 1. Flowchart of the enzymatic delignification of wood biomass using ionic liquids as pretreatment agents
and cosolvents.
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Absorbance at 280 nm
2.5
y = 20.62x + 0.005
R² = 0.999
2
1.5
1
0.5
0
0
0.02
0.04
0.06
0.08
0.1
0.12
Lignin concentration [mg/mL]
Figure 2. Calibration curve of alkali lignin dissolved 0.1 M NaOH containing 0.2 wt% IL [emim][OAc]
2.3 Characterization of treated and untreated wood materials
2.3.1 Morphology of materials
The fibers morphology was characterized using a scanning electron microscope (SEM) (S-4700, Hitachi Ltd.,
Tokyo, Japan). For SEM images, fibers were mounted on metal stubs by double- faced tape and images were
taken. Prior to imaging samples were coated with gold–palladium in a sputter coater (E1030 Ion Sputter, Hitachi
Ltd.).
2.3.2 Fourier transform infrared spectroscopy (FTIR)
The FTIR spectra of the samples were recorded from a KBr disk containing 1% finely ground samples on an
IRPrestise-21 FTIR spectrophotometer (Shimadzu, Japan) in the range of 4000–400 cm−1 with a resolution of 4
cm-1. Spectral outputs were recorded in the transmittance mode as a function of wave number.
2.3.3 Powder X-ray diffraction (PXRD)
The crystallinity of the untreated and treated wood materials was investigated by powder X-ray diffractometry
(PXRD), using a XRD-6100 Diffraction System (Shimadzu, Japan). The diffraction patterns were measured
from 2θ = 8–40° with scan speed of 0.1° min−1 using Cu Kα radiation at 40 kV and 30 mA.
3. Results and discussion
3.1 Ionic liquid pretreatment of wood biomass
Pretreatment of wood biomass (10 wt%) with IL [bmim][Cl] and [emim][OAc] was carried out at moderate
conditions (80 °C, 1-3 hrs) to swell the wood cell by partial dissolution. Here, we have selected these two ILs
because they are able to dissolve wood materials at higher temperatures (Kilpelainen et al., 2007; Sun et al.,
2009). In general, temperatures from 80 to 130 °C have been used to dissolve wood materials in ILs (Kilpelainen
et al., 2007; Fort et al., 2007). Although, elevated temperatures (100 °C or higher) lead to complete dissolution
of wood biomass which favors delignification efficiency, the crystallinity of regenerated cellulose rich materials
decreased and loss of biopolymer increased significantly (Labbe et al., 2012; Lucas et. 2011; Wang et al., 2011;
Weerachanchai et al., 2012). For this work, we have selected moderate temperature during IL pretreatment so
that the major components of wood particularly, cellulose loss were minimized. In addition, cellulose can also be
extracted with minimum structural alteration. After completing pretreatement at 80 °C under vigorous
mechanical stirring, the colors of the mixture became dark and their viscosities increased, indicating that patial
dissolution of wood occurred. Then, the mixture was diluted with acetate buffer and enzymatic delignification
was conducted as stated in the experimental section.
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Figure 3. Catalytic cycle of a laccase-mediator lignin degradation system.
3.2 Enzymatic delignification of IL treated and untreated wood biomass
Enzymatic delignification of IL treated wood biomass was investigated using two type of ILs. Catalytic cycle of
a laccase-mediator lignin degradation system is shown is Figure 3. The results obtained from enzymatic
delignification in IL alone and IL-aqueous systems are shown in Table 1. For comparison, enzymatic
delignification in aqueous systems and delignification in ILpretreatment were also performed. The results clearly
demonstrated that enzymatic delignification of wood biomass swollen by IL prior to enzymatic delignification
could be an efficient method for the removal of lignin to extract cellulose fibers. Comapred to IL [bmim][Cl], IL
[emim][OAc] was found to be suitable for pretaement of wood biomass and enzymatic deliglification (entries
3&5), possibly, due to its high ability in dissolution of wood (Sun et al., 2009), and its enzyme compatible nature
(Zhao et al., 2008). Another possible reason of lower delignification efficiency using IL [bmim][Cl] is well
known adverse effect of Cl- on enzyme performace (Lee et al., 2006). It is clearly indicated from Table 1 that IL
pretreatment did not significantly change the lignin composition of wood materials but did alter the structure to
render a more accessible surface area for enzyme. Since IL [emim][OAc] gave the best results, this IL will be
used for subsequent experiments. The enhanced process efficiency with IL [emim][OAc] may be a combination
of factors. First, the swollen of ground wood may increase the available surface area to the enzymes. In addition,
ILs can dissolve some lignin during swollen, which can lead to increase the enzyme accessibility. Note that IL
[emim][OAc] was found to be selective for lignin during pretreatment of wood biomass ( Lee et al., 2009)
Second, the substrate and product solubility are expected to increase by using ILs, which are responsible for low
delignification efficiency in aqueous system.
Table 1. Lignin extraction from wood biomass with different methods
for pretreatment
Reaction media for enzymatic
delignification
1
No IL pretreatment
Enzymatic delignification in acetic buffer c
10.2
2
No IL pretreatment
5% (w/w) IL[bmim][Cl] in buffer
3.1
3
No IL pretreatment
5% (w/w) IL[ emim][OAc] in buffer
entry
Ionic liquid used
a
4
5
6
a
[bmim][Cl]
[emim][OAc]
[emim][OAc]
5% (w/w) IL[bmim][Cl] in buffer
Extracted
ligninb
5% (w/w) IL [ emim][OAc] in buffer
No enzymatic delignification
e
16.5
d
14.2
d
48.4
7.0
200 mg of ground wood were incubated in 2g IL at 80ºC with vigorous magnetic stirring for 1hr
b
results are expressed as a percentage of extracted lignin relative to lignin content in the original ground wood.
The data are the average of three experiments.
c
reaction conditions: 200 mg untreated wood, 10 mL of 100 mM sodium acetate buffer (pH = 4.5), 50 U laccase,
50°C, 24 hr and 1-hydroxybenzotriazole (HBT) = 3 mg.
d
200 mg wood, buffer 38 mL, 23 hr and other reaction conditions are the same as for entry 1;
e
200 mg wood swollen by 2 g IL, buffer 38 mL, 50°C and 23 hr.
3.3 Effect of pretreatment time
To understand the correlation of wood biomass enzymatic delignification with IL pretreatment time, various
samples of IL[emim][OAc]-pretreated wood biomass were prepared by changing the treatment time in the IL.
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Extracted lignin [%]
Generally, long cooking time increases the delignification efficiency; however use of energy becomes very
important at long cooking time. The incubation time for pretreatment of wood in in IL was varied from 0.5 to 3 h
at 80 °C (see Figure 4). It was found that delignification efficiency increased with increasing pretreatment time.
For example, pretreatment time from 0.5 to 3 hr, the delignification efficiency for wood biomass increased from
24.1 to 64.8%. This result is consistent what have been reported in the literature (Lee et al., 2009). One possible
explanation is that IL pretreatment of wood biomass can easily swell cell walls to weaken the network of
biomass components, which leads to dissolution of wood in IL with pretreated time (Lee et al., 2009).
Consequently, lignin extraction was promoted due to the dissolution of biomass with iincubation time. However,
the crystallinity of recovered cellulose rich fibers decreases with the increase in preatreatment time as shown in
Figure 5. Since, our objective is to extract cellulose fibers with minimum structural alteration, we used
ptratement time 1 hr, as compromise between high delignification and high crytallnity of the cellulose rich
materials, for subsequent experiments.
0.5
1
2
Pretreatment time [hr]
3
Intensity [counts]
Figure 4. Effect of cooking time in IL [emim][OAc] on delignification of wood biomass. 200 mg of ground
wood were incubated in 2g IL at 80ºC with vigorous magnetic stirring. Enzymatic delignification
conditions are the same as entry 1 shown in Table 1.
a
b
c
8
16
24
32
2θ
Figure 5. X-ray diffraction spectra of wood biomass pretreated with IL for (a) 1 hr, (b) 2 hr and (c) 3 hr followed
by enzymatic delignification.
3.4 Chracterization of treated and untretaed wood materials
Our next aim was to characterize treated and untreated wood fibers using different techniques in order to better
understand compositional and structural impacts. As shown in SEM images (Fig. 6), pretreated wood fibers have
shown a different morphology compared to untreated wood materials. In cellulose rich materials, wood cell
networks composed of cellulose, hemicellulose and lignin were broken down and cellulose fibers were partially
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separated into individual microsized fibers (Fig. 6b). Significantly, obtained cellulose rich materials have smooth
and clean surfaces (data not shown) because most of the non-cellulosic materials (e.g., lignin) were removed
during the IL and enzymatic delignification.
B
A
Figure 6. SEM images of (a) Untreated ground wood, and (b) the corresponding enzymatic treated wood fibers
(entry 5 in Table 1). Picture of treated and untreated wood biomass is shown in inset.
Transmittance [%]
b
a
4000
3500
3000
2500
2000
1500
1000
500
Wavenumber [cm-1]
Figure 7. FTIR spectra for (a) untreated wood materials, (b) IL Treated wood fibers followed by enzymatic
delignification.
The FTIR spectra of the untreated and treated samples were measured and are compared in Figure 7. The
dominant peaks at ca. 3346 cm-1 (O-H stretch) and ca. 2892 cm-1 (C-H stretch) represent the aliphatic moieties
present in major wood material biopolymers. The prominent peak at 1731 cm-1 in the untreated wood materials is
attributed to a C=O stretching vibration in acetyl groups of the hemicelluloses (Labbe et al., 2005). The
characteristic peaks of lignin at 1592/1503 (C=C stretching vibration), 1256 cm-1 (asymmetric bending in CH3),
and 1251 cm-1 (C-O vibration in the syringyl ring) (Labbe et al., 2005) disappeared after IL pretreatment
followed by enzymatic delignification due to the removal of most of the lignin. The absorbance bands at 1150
cm-1, 1052 cm-1 and 896 cm-1, corresponding to C-O-C asymmetric bridge stretching vibration in
cellulose/hemicellulose, C-O stretching vibration in cellulose/hemicellulose, and C-H deformation vibration in
cellulose, respectively, (Labbe et al., 2005), were more resolved in the obtained cellulose rich materials,
indicating that the produced cellulose-rich wood fibers are richer in carbohydrates, consistent with our chemical
composition study.
4. Conclusions
This study reported an environmentally friendly and efficient approach which was comprised ionic liquid
pretreatment followed by enzymatic delignification for isolating cellulose fibers with minimum structural
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alteration from wood biomass. IL[emim][OAc] has been found to be a better solvent/agent than [bmim][Cl] for
wood pretreatment and enzymatic delignification. Compared to conventional delignification of wood biomass in
aqueous system, delignification efficiency was increased significantly for IL treated wood; at optimized
condition about 65% delignification was obtained where as it was about 10.2 % without IL pretreatment. This
enhanced efficiency was due to the improved solubility of substrates and products in ILs and easy enzyme
accessibility to the IL swollen wood cell prior to the delignification. The produced cellulose rich materials were
characterized by acid hydrolysis, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy
(SEM) and X-ray diffractometry (XRD). SEM and XRD revealed considerable microstructural and crystallinity
index changes in the pretreated cellulose rich materials. The combination of IL pretreatment and enzymatic
delignification may provide a platform for cellulosic biomass to biomaterials, biopolymers, biofuels, bioplastics
and hydrocarbons.
Acknowledgements
This work was supported by the Okayama Prefecture Green Project, Japan. We also gratefully acknowledge
Universiti Teknologi PETRONAS for the necessary funding (STIRF 14/2013) for this work.
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