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Sample records for lignocellulosic biomass

  1. Method for pretreating lignocellulosic biomass

    SciTech Connect

    Kuzhiyil, Najeeb M.; Brown, Robert C.; Dalluge, Dustin Lee

    2015-08-18

    The present invention relates to a method for pretreating lignocellulosic biomass containing alkali and/or alkaline earth metal (AAEM). The method comprises providing a lignocellulosic biomass containing AAEM; determining the amount of the AAEM present in the lignocellulosic biomass; identifying, based on said determining, the amount of a mineral acid sufficient to completely convert the AAEM in the lignocellulosic biomass to thermally-stable, catalytically-inert salts; and treating the lignocellulosic biomass with the identified amount of the mineral acid, wherein the treated lignocellulosic biomass contains thermally-stable, catalytically inert AAEM salts.

  2. Hydrothermal carbonization of lignocellulosic biomass.

    PubMed

    Xiao, Ling-Ping; Shi, Zheng-Jun; Xu, Feng; Sun, Run-Cang

    2012-08-01

    Hydrothermal carbonization (HTC) is a novel thermochemical conversion process to convert lignocellulosic biomass into value-added products. HTC processes were studied using two different biomass feedstocks: corn stalk and Tamarix ramosissima. The treatment brought an increase of the higher heating values up to 29.2 and 28.4 MJ/kg for corn stalk and T. ramosissima, respectively, corresponding to an increase of 66.8% and 58.3% as compared to those for the raw materials. The resulting lignite-like solid products contained mainly lignin with a high degree of aromatization and a large amount of oxygen-containing groups. Liquid products extracted with ethyl acetate were analyzed by gas chromatography-mass spectrometry. The identified degradation products were phenolic compounds and furan derivatives, which may be desirable feedstocks for biodiesel and chemical production. Based on these results, HTC is considered to be a potential treatment in a lignocellulosic biomass refinery.

  3. Fungal pretreatment of lignocellulosic biomass.

    PubMed

    Wan, Caixia; Li, Yebo

    2012-01-01

    Pretreatment is a crucial step in the conversion of lignocellulosic biomass to fermentable sugars and biofuels. Compared to thermal/chemical pretreatment, fungal pretreatment reduces the recalcitrance of lignocellulosic biomass by lignin-degrading microorganisms and thus potentially provides an environmentally-friendly and energy-efficient pretreatment technology for biofuel production. This paper provides an overview of the current state of fungal pretreatment by white rot fungi for biofuel production. The specific topics discussed are: 1) enzymes involved in biodegradation during the fungal pretreatment; 2) operating parameters governing performance of the fungal pretreatment; 3) the effect of fungal pretreatment on enzymatic hydrolysis and ethanol production; 4) efforts for improving enzymatic hydrolysis and ethanol production through combinations of fungal pretreatment and physical/chemical pretreatment; 5) the treatment of lignocellulosic biomass with lignin-degrading enzymes isolated from fungal pretreatment, with a comparison to fungal pretreatment; 6) modeling, reactor design, and scale-up of solid state fungal pretreatment; and 7) the limitations and future perspective of this technology.

  4. Lime pretreatment of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Chang, Shushien

    Lignocellulose is a valuable alternative energy source. The susceptibility of lignocellulosic biomass to enzymatic hydrolysis is constrained due to its structural features, so pretreatment is essential to enhance enzymatic digestibility. Of the chemicals used as pretreatment agents, it has been reported that alkalis improve biomass digestibility significantly. In comparison with other alkalis such as NaOH and ammonia, lime (calcium hydroxide) has many advantages; it is very inexpensive, is safe, and can be recovered by carbonating wash water. The effects of lime pretreatment were explored on switchgrass and poplar wood, representing herbaceous and woody biomass, respectively. The effects of pretreatment conditions (time, temperature, lime loading, water loading, particle size, and oxygen pressure) have been systematically studies. Lime alone enhances the digestibility of switchgrass significantly; under the recommended conditions, the 3-d total sugar (glucose + xylose) yields of lime-treated switchgrass were 7 times that of untreated sample. When treating poplar wood, lime must be combined with oxygen to achieve high digestibility; oxidative lime pretreatment increased the 3-d total sugar yield of poplar wood to 12 times that of untreated sample. In a fundamental study, to determine why lime pretreatment is effective, the effects of three structural features on enzymatic digestibility were studied: lignin content, acetyl content, and crystallinity index (CrI). Poplar wood was treated with peracetic acid, potassium hydroxide, and ball milling to produce model lignocelluloses with a broad spectrum of lignin contents, acetyl contents, and CrI, respectively. Enzymatic hydrolysis was performed on the model lignocelluloses to determine the digestibility. Correlations between lignin/carbohydrate ratio, acetyl/carbohydrate ratio, CrI and digestibility were developed. The 95% prediction intervals show that the correlations predict the 1-h and 3-d total sugar conversions of

  5. Lignocellulosic Biomass Pretreatment Using AFEX

    NASA Astrophysics Data System (ADS)

    Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P. S.; Marshall, Derek; Dale, Bruce E.

    Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

  6. Lignocellulosic biomass pretreatment using AFEX.

    PubMed

    Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P S; Marshall, Derek; Dale, Bruce E

    2009-01-01

    Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

  7. Pretreatment of lignocellulosic biomass using Fenton chemistry

    USDA-ARS?s Scientific Manuscript database

    Pretreatment is a necessary step in “biomass to biofuel conversion” due to the recalcitrant nature of lignocellulosic biomass. White-rot fungi utilize peroxidases and hydrogen peroxide (in vivo Fenton chemistry) to degrade lignin. In an attempt to mimic this process, solution phase Fenton chemistry ...

  8. Lignocellulosic biomass conversion to ethanol by Saccharomyces

    USDA-ARS?s Scientific Manuscript database

    As interest in alternative energy sources rises, the concept of agriculture as an energy producer has become increasingly attractive (Outlaw et al. 2005). Renewable biomass, including lignocellulosic materials and agricultural residues, are low-cost materials for bioethanol production (Bothast and ...

  9. Catalytic fast pyrolysis of lignocellulosic biomass.

    PubMed

    Liu, Changjun; Wang, Huamin; Karim, Ayman M; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel-bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating value, high corrosiveness, high viscosity, and instability; they also greatly limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  10. Catalytic fast pyrolysis of lignocellulosic biomass

    SciTech Connect

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  11. Anaerobic digestion of lignocellulosic biomass: challenges and opportunities.

    PubMed

    Sawatdeenarunat, Chayanon; Surendra, K C; Takara, Devin; Oechsner, Hans; Khanal, Samir Kumar

    2015-02-01

    Anaerobic digestion (AD) of lignocellulosic biomass provides an excellent opportunity to convert abundant bioresources into renewable energy. Rumen microorganisms, in contrast to conventional microorganisms, are an effective inoculum for digesting lignocellulosic biomass due to their intrinsic ability to degrade substrate rich in cellulosic fiber. However, there are still several challenges that must be overcome for the efficient digestion of lignocellulosic biomass. Anaerobic biorefinery is an emerging concept that not only generates bioenergy, but also high-value biochemical/products from the same feedstock. This review paper highlights the current status of lignocellulosic biomass digestion and discusses its challenges. The paper also discusses the future research needs of lignocellulosic biomass digestion.

  12. Hydrolysis and fractionation of lignocellulosic biomass

    DOEpatents

    Torget, Robert W.; Padukone, Nandan; Hatzis, Christos; Wyman, Charles E.

    2000-01-01

    A multi-function process is described for the hydrolysis and fractionation of lignocellulosic biomass to separate hemicellulosic sugars from other biomass components such as extractives and proteins; a portion of the solubilized lignin; cellulose; glucose derived from cellulose; and insoluble lignin from said biomass comprising one or more of the following: optionally, as function 1, introducing a dilute acid of pH 1.0-5.0 into a continual shrinking bed reactor containing a lignocellulosic biomass material at a temperature of about 94 to about 160.degree. C. for a period of about 10 to about 120 minutes at a volumetric flow rate of about 1 to about 5 reactor volumes to effect solubilization of extractives, lignin, and protein by keeping the solid to liquid ratio constant throughout the solubilization process; as function 2, introducing a dilute acid of pH 1.0-5.0, either as virgin acid or an acidic stream from another function, into a continual shrinking bed reactor containing either fresh biomass or the partially fractionated lignocellulosic biomass material from function 1 at a temperature of about 94-220.degree. C. for a period of about 10 to about 60 minutes at a volumetric flow rate of about 1 to about 5 reactor volumes to effect solubilization of hemicellulosic sugars, semisoluble sugars and other compounds, and amorphous glucans by keeping the solid to liquid ratio constant throughout the solubilization process; as function 3, optionally, introducing a dilute acid of pH 1.0-5.0 either as virgin acid or an acidic stream from another function, into a continual shrinking bed reactor containing the partially fractionated lignocellulosic biomass material from function 2 at a temperature of about 180-280.degree. C. for a period of about 10 to about 60 minutes at a volumetric flow rate of 1 to about 5 reactor volumes to effect solubilization of cellulosic sugars by keeping the solid to liquid ratio constant throughout the solubilization process; and as function 4

  13. Genetic manipulation of lignocellulosic biomass for bioenergy.

    PubMed

    Wang, Peng; Dudareva, Natalia; Morgan, John A; Chapple, Clint

    2015-12-01

    Lignocellulosic biomass represents an abundant and sustainable raw material for biofuel production. The recalcitrance of biomass to degradation increases the estimated cost of biofuel production and limits its competitiveness in the market. Genetic engineering of lignin, a major recalcitrance factor, improves saccharification and thus the potential yield of biofuels. Recently, our understanding of lignification and its regulation has been advanced by new studies in various systems, all of which further enhances our ability to manipulate the biosynthesis and deposition of lignin in energy crops for producing cost-effective second generation biofuels.

  14. Engineering microbial surfaces to degrade lignocellulosic biomass

    PubMed Central

    Huang, Grace L; Anderson, Timothy D; Clubb, Robert T

    2014-01-01

    Renewable lignocellulosic plant biomass is a promising feedstock from which to produce biofuels, chemicals, and materials. One approach to cost-effectively exploit this resource is to use consolidating bioprocessing (CBP) microbes that directly convert lignocellulose into valuable end products. Because many promising CBP-enabling microbes are non-cellulolytic, recent work has sought to engineer them to display multi-cellulase containing minicellulosomes that hydrolyze biomass more efficiently than isolated enzymes. In this review, we discuss progress in engineering the surfaces of the model microorganisms: Bacillus subtilis, Escherichia coli, and Saccharomyces cerevisiae. We compare the distinct approaches used to display cellulases and minicellulosomes, as well as their surface enzyme densities and cellulolytic activities. Thus far, minicellulosomes have only been grafted onto the surfaces of B. subtilis and S. cerevisiae, suggesting that the absence of an outer membrane in fungi and Gram-positive bacteria may make their surfaces better suited for displaying the elaborate multi-enzyme complexes needed to efficiently degrade lignocellulose. PMID:24430239

  15. Preprocessing Moist Lignocellulosic Biomass for Biorefinery Feedstocks

    SciTech Connect

    Neal Yancey; Christopher T. Wright; Craig Conner; J. Richard Hess

    2009-06-01

    Biomass preprocessing is one of the primary operations in the feedstock assembly system of a lignocellulosic biorefinery. Preprocessing is generally accomplished using industrial grinders to format biomass materials into a suitable biorefinery feedstock for conversion to ethanol and other bioproducts. Many factors affect machine efficiency and the physical characteristics of preprocessed biomass. For example, moisture content of the biomass as received from the point of production has a significant impact on overall system efficiency and can significantly affect the characteristics (particle size distribution, flowability, storability, etc.) of the size-reduced biomass. Many different grinder configurations are available on the market, each with advantages under specific conditions. Ultimately, the capacity and/or efficiency of the grinding process can be enhanced by selecting the grinder configuration that optimizes grinder performance based on moisture content and screen size. This paper discusses the relationships of biomass moisture with respect to preprocessing system performance and product physical characteristics and compares data obtained on corn stover, switchgrass, and wheat straw as model feedstocks during Vermeer HG 200 grinder testing. During the tests, grinder screen configuration and biomass moisture content were varied and tested to provide a better understanding of their relative impact on machine performance and the resulting feedstock physical characteristics and uniformity relative to each crop tested.

  16. Pretreatments to enhance the digestibility of lignocellulosic biomass.

    PubMed

    Hendriks, A T W M; Zeeman, G

    2009-01-01

    Lignocellulosic biomass represents a rather unused source for biogas and ethanol production. Many factors, like lignin content, crystallinity of cellulose, and particle size, limit the digestibility of the hemicellulose and cellulose present in the lignocellulosic biomass. Pretreatments have as a goal to improve the digestibility of the lignocellulosic biomass. Each pretreatment has its own effect(s) on the cellulose, hemicellulose and lignin; the three main components of lignocellulosic biomass. This paper reviews the different effect(s) of several pretreatments on the three main parts of the lignocellulosic biomass to improve its digestibility. Steam pretreatment, lime pretreatment, liquid hot water pretreatments and ammonia based pretreatments are concluded to be pretreatments with high potentials. The main effects are dissolving hemicellulose and alteration of lignin structure, providing an improved accessibility of the cellulose for hydrolytic enzymes.

  17. Extrusion Pretreatment of Lignocellulosic Biomass: A Review

    PubMed Central

    Zheng, Jun; Rehmann, Lars

    2014-01-01

    Bioconversion of lignocellulosic biomass to bioethanol has shown environmental, economic and energetic advantages in comparison to bioethanol produced from sugar or starch. However, the pretreatment process for increasing the enzymatic accessibility and improving the digestibility of cellulose is hindered by many physical-chemical, structural and compositional factors, which make these materials difficult to be used as feedstocks for ethanol production. A wide range of pretreatment methods has been developed to alter or remove structural and compositional impediments to (enzymatic) hydrolysis over the last few decades; however, only a few of them can be used at commercial scale due to economic feasibility. This paper will give an overview of extrusion pretreatment for bioethanol production with a special focus on twin-screw extruders. An economic assessment of this pretreatment is also discussed to determine its feasibility for future industrial cellulosic ethanol plant designs. PMID:25334065

  18. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    PubMed Central

    Lee, H. V.; Hamid, S. B. A.; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein. PMID:25247208

  19. Evaluation of four ionic liquids for pretreatment of lignocellulosic biomass

    PubMed Central

    2014-01-01

    Background Lignocellulosic biomass is highly recalcitrant and various pretreatment techniques are needed to facilitate its effective enzymatic hydrolysis to produce sugars for further conversion to bio-based chemicals. Ionic liquids (ILs) are of interest in pretreatment because of their potential to dissolve lignocellulosic materials including crystalline cellulose. Results Four imidazolium-based ionic liquids (ILs) ([C=C2C1im][MeCO2], [C4C1im][MeCO2], [C4C1im][Cl], and [C4C1im][HSO4]) well known for their capability to dissolve lignocellulosic species were synthesized and then used for pretreatment of substrates prior to enzymatic hydrolysis. In order to achieve a broad evaluation, seven cellulosic, hemicellulosic and lignocellulosic substrates, crystalline as well as amorphous, were selected. The lignocellulosic substrates included hybrid aspen and Norway spruce. The monosaccharides in the enzymatic hydrolysate were determined using high-performance anion-exchange chromatography. The best results, as judged by the saccharification efficiency, were achieved with [C4C1im][Cl] for cellulosic substrates and with the acetate-based ILs for hybrid aspen and Norway spruce. After pretreatment with acetate-based ILs, the conversion to glucose of glucan in recalcitrant softwood lignocellulose reached similar levels as obtained with pure crystalline and amorphous cellulosic substrates. IL pretreatment of lignocellulose resulted in sugar yields comparable with that obtained with acidic pretreatment. Heterogeneous dissolution with [C4C1im][HSO4] gave promising results with aspen, the less recalcitrant of the two types of lignocellulose included in the investigation. Conclusions The ability of ILs to dissolve lignocellulosic biomass under gentle conditions and with little or no by-product formation contributes to making them highly interesting alternatives for pretreatment in processes where high product yields are of critical importance. PMID:24779378

  20. Ionic liquids: Promising green solvents for lignocellulosic biomass utilization

    DOE PAGES

    Yoo, Chang Geun; Pu, Yunqiao; Ragauskas, Arthur J.

    2017-06-01

    Ionic liquids are effective solvents/media for the utilization of lignocellulosic biomass. The unique properties of ionic liquids enable them to effectively dissolve and/or convert the biomass into various types of products. This review aims to cover the latest progress achieved in applications of ionic liquids on biomass conversion and analysis. Specifically, several recently developed approaches on how to overcome current challenges on the use of ionic liquids in the biomass conversion were highlighted. Here, recent studies addressing the potential applications of ionic liquids for the production of novel biomass-derived chemicals and materials were also discussed.

  1. Flow-through biological conversion of lignocellulosic biomass

    DOEpatents

    Herring, Christopher D.; Liu, Chaogang; Bardsley, John

    2014-07-01

    The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars, or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.

  2. Polyols and polyurethanes from the liquefaction of lignocellulosic biomass.

    PubMed

    Hu, Shengjun; Luo, Xiaolan; Li, Yebo

    2014-01-01

    Polyurethanes (PUs), produced from the condensation polymerizations between polyols and isocyanates, are one of the most versatile polymer families. Currently, both polyols and isocyanates are largely petroleum derived. Recently, there have been extensive research interests in developing bio-based polyols and PUs from renewable resources. As the world's most abundant renewable biomass, lignocellulosic biomass is rich in hydroxyl groups and has potential as a feedstock to produce bio-based polyols and PUs. Lignocellulosic biomass can be converted to liquid polyols for PU applications through acid- or base-catalyzed atmospheric liquefaction processes using polyhydric alcohols as liquefaction solvents. Biomass liquefaction-derived polyols can be used to prepare various PU products, such as foams, films and adhesives. The properties of biomass liquefaction-derived polyols and PUs depend on various factors, such as feedstock characteristics, liquefaction conditions, and PU formulations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Flow-through biological conversion of lignocellulosic biomass

    DOEpatents

    Herring, Christopher D.; Liu, Chaogang; Bardsley, John

    2014-07-01

    The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars, or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.

  4. Methods for producing extracted and digested products from pretreated lignocellulosic biomass

    DOEpatents

    Chundawat, Shishir; Sousa, Leonardo Da Costa; Cheh, Albert M.; Balan; , Venkatesh; Dale, Bruce

    2017-05-16

    Methods for producing extracted and digested products from pretreated lignocellulosic biomass are provided. The methods include converting native cellulose I.sub..beta. to cellulose III.sub.I by pretreating the lignocellulosic biomass with liquid ammonia under certain conditions, and performing extracting or digesting steps on the pretreated/converted lignocellulosic biomass.

  5. Sophorolipid production from lignocellulosic biomass feedstocks

    NASA Astrophysics Data System (ADS)

    Samad, Abdul

    , the yield of SLs was 0.55 g/g carbon (sugars plus oil) for cultures with bagasse hydrolysates. Further, SL production was investigated using sweet sorghum bagasse and corn stover hydrolysates derived from different pretreatment conditions. For the former and latter sugar sources, yellow grease or soybean oil was supplemented at different doses to enhance sophorolipid yield. 14-day batch fermentation on bagasse hydrolysates with 10, 40 and 60 g/L of yellow grease had cell densities of 5.7 g/L, 6.4 g/L and 7.8 g/L, respectively. The study also revealed that the yield of SLs on bagasse hydrolysate decreased from 0.67 to 0.61 and to 0.44 g/g carbon when yellow grease was dosed at 10, 40 and 60 g/L. With aforementioned increasing yellow grease concentration, the residual oil left after 14 days was recorded as 3.2 g/L, 8.5 g/L and 19.9 g/L. For similar experimental conditions, the cell densities observed for corn stover hydrolysate combined with soybean oil at 10, 20 and 40 g/L concentration were 6.1 g/L, 5.9 g/L, and 5.4 g/L respectively. Also, in the same order of oil dose supplemented, the residual oil recovered after 14-day was 8.5 g/L, 8.9 g/L, and 26.9 g/L. Corn stover hydrolysate mixed with the 10, 20 and 40 g/L soybean oil, the SL yield was 0.19, 0.11 and 0.09 g/g carbon. Overall, both hydrolysates supported cell growth and sophorolipid production. The results from this research show that hydrolysates derived from the different lignocellulosic biomass feedstocks can be utilized by C. bombicola to achieve substantial yields of SLs. Based upon the results revealed by several batch-stage experiments, it can be stated that there is great potential for scaling up and industrial scale production of these high value products in future.

  6. [Progress on cellulase and enzymatic hydrolysis of lignocellulosic biomass].

    PubMed

    Fang, Xu; Qin, Yuqi; Li, Xuezhi; Wang, Lushan; Wang, Tianhong; Zhu, Mingtian; Qu, Yinbo

    2010-07-01

    Biofuels and bio-based chemicals from lignocellulosic biomass are sustainable, making them alternatives to petroleum-derived fuels and chemicals to address the challenges of the shortage of crude oil supply and climate change resulted from the overconsumption of petroleum-based products, particularly in China. However, high cost in liberating sugars from lignocellulosic biomass is still the bottleneck of the commercialization of biofuels and bio-based chemicals. In this article, the major components of cellulases and their synergistic role in the hydrolysis of pre-treated biomass is reviewed, followed by how to evaluate the enzymatic hydrolysis. With the elucidation of the underlying mechanism of the conformations of the enzyme molecules and their effectiveness in attacking cellulose substrate, more efficient enzymes are expected to be developed. Using the high production strain Penicillium decumbens, the on-site production of cellulases for cellulose ethanol production is discussed.

  7. Unlocking the potential of lignocellulosic biomass through plant science.

    PubMed

    Marriott, Poppy E; Gómez, Leonardo D; McQueen-Mason, Simon J

    2016-03-01

    The aim of producing sustainable liquid biofuels and chemicals from lignocellulosic biomass remains high on the sustainability agenda, but is challenged by the costs of producing fermentable sugars from these materials. Sugars from plant biomass can be fermented to alcohols or even alkanes, creating a liquid fuel in which carbon released on combustion is balanced by its photosynthetic capture. Large amounts of sugar are present in the woody, nonfood parts of crops and could be used for fuel production without compromising global food security. However, the sugar in woody biomass is locked up in the complex and recalcitrant lignocellulosic plant cell wall, making it difficult and expensive to extract. In this paper, we review what is known about the major polymeric components of woody plant biomass, with an emphasis on the molecular interactions that contribute to its recalcitrance to enzymatic digestion. In addition, we review the extensive research that has been carried out in order to understand and reduce lignocellulose recalcitrance and enable more cost-effective production of fuel from woody plant biomass.

  8. Fungal treated lignocellulosic biomass as ruminant feed ingredient: a review.

    PubMed

    van Kuijk, S J A; Sonnenberg, A S M; Baars, J J P; Hendriks, W H; Cone, J W

    2015-01-01

    In ruminant nutrition, there is an increasing interest for ingredients that do not compete with human nutrition. Ruminants are specialists in digesting carbohydrates in plant cell walls; therefore lignocellulosic biomass has potential in ruminant nutrition. The presence of lignin in biomass, however, limits the effective utilization of cellulose and hemicellulose. Currently, most often chemical and/or physical treatments are used to degrade lignin. White rot fungi are selective lignin degraders and can be a potential alternative to current methods which involve potentially toxic chemicals and expensive equipment. This review provides an overview of research conducted to date on fungal pretreatment of lignocellulosic biomass for ruminant feeds. White rot fungi colonize lignocellulosic biomass, and during colonization produce enzymes, radicals and other small compounds to breakdown lignin. The mechanisms on how these fungi degrade lignin are not fully understood, but fungal strain, the origin of lignocellulose and culture conditions have a major effect on the process. Ceriporiopsis subvermispora and Pleurotus eryngii are the most effective fungi to improve the nutritional value of biomass for ruminant nutrition. However, conclusions on the effectiveness of fungal delignification are difficult to draw due to a lack of standardized culture conditions and information on fungal strains used. Methods of analysis between studies are not uniform for both chemical analysis and in vitro degradation measurements. In vivo studies are limited in number and mostly describing digestibility after mushroom production, when the fungus has degraded cellulose to derive energy for fruit body development. Optimization of fungal pretreatment is required to shorten the process of delignification and make it more selective for lignin. In this respect, future research should focus on optimization of culture conditions and gene expression to obtain a better understanding of the mechanisms

  9. Processes for pretreating lignocellulosic biomass: A review

    SciTech Connect

    McMillan, J D

    1992-11-01

    This paper reviews existing and proposed pretreatment processes for biomass. The focus is on the mechanisms by which the various pretreatments act and the influence of biomass structure and composition on the efficacy of particular pretreatment techniques. This analysis is used to identify pretreatment technologies and issues that warrant further research.

  10. Processes for pretreating lignocellulosic biomass: A review

    SciTech Connect

    McMillan, J.D.

    1992-11-01

    This paper reviews existing and proposed pretreatment processes for biomass. The focus is on the mechanisms by which the various pretreatments act and the influence of biomass structure and composition on the efficacy of particular pretreatment techniques. This analysis is used to identify pretreatment technologies and issues that warrant further research.

  11. Enhancing Cellulase Commercial Performance for the Lignocellulosic Biomass Industry

    SciTech Connect

    Jarnigan, Alisha

    2016-06-07

    Cellulase enzyme loading (Bt-G) for the economic conversion of lignocellulosic biomass to ethanol is on of the key challenges identified in the Biomass Program of DOE/EERE. The goal of Danisco’s project which ran from 2008 to 2012, was to address the technical challenge by creating more efficient enzyme that could be used at lower doses, thus reducing the enzymes’ cost contribution to the conversio process. We took the approach of protein engineering of cellulase enzymes to overcome the enzymati limitations in the system of cellulosic-hydrolyzing enzymes to improve performance in conversion o biomass, thereby creating a more effective enzyme mix.

  12. Understanding Ionic Liquid Pretreatment of Lignocellulosic Biomasses

    USDA-ARS?s Scientific Manuscript database

    Pretreatment of biomass is essential for breaking apart highly ordered and crystalline plant cell walls and loosening the lignin and hemicellulose conjugation to cellulose microfibrills, thereby facilitating enzyme accessibility and adsorption and reducing costs of downstream saccharification proces...

  13. Process for the treatment of lignocellulosic biomass

    DOEpatents

    Dale, Bruce E.

    2014-07-08

    A process for the treatment of biomass to render structural carbohydrates more accessible and/or digestible using concentrated ammonium hydroxide with or without anhydrous ammonia addition, is described. The process preferably uses steam to strip ammonia from the biomass for recycling. The process yields of monosaccharides from the structural carbohydrates are good, particularly as measured by the enzymatic hydrolysis of the structural carbohydrates. The monosaccharides are used as animal feeds and energy sources for ethanol production.

  14. Process for the treatment of lignocellulosic biomass

    DOEpatents

    Dale, Bruce E.; Lynd, Lee R.; Laser, Mark

    2013-03-12

    A process for the treatment of biomass to render structural carbohydrates more accessible and/or digestible using concentrated ammonium hydroxide with or without anhydrous ammonia addition, is described. The process preferably uses steam to strip ammonia from the biomass for recycling. The process yields of monosaccharides from the structural carbohydrates are good, particularly as measured by the enzymatic hydrolysis of the structural carbohydrates. The monosaccharides are used as animal feeds and energy sources for ethanol production.

  15. Lignocellulosic Biomass Pretreatment: A Key to Its Successful Bioconversion to Fuel Ethanol

    USDA-ARS?s Scientific Manuscript database

    Native lignocellulosic biomass is very resistant to degradation by enzymes. Prior pretreatment is essential for efficient conversion of lignocellulosic feedstock to ethanol. In this presentation, various pretreatment options such as dilute acid, alkali, alkaline peroxide, wet oxidation, steam expl...

  16. FRACTIONATION OF LIGNOCELLULOSIC BIOMASS FOR FUEL-GRADE ETHANOL PRODUCTION

    SciTech Connect

    F.D. Guffey; R.C. Wingerson

    2002-10-01

    PureVision Technology, Inc. (PureVision) of Fort Lupton, Colorado is developing a process for the conversion of lignocellulosic biomass into fuel-grade ethanol and specialty chemicals in order to enhance national energy security, rural economies, and environmental quality. Lignocellulosic-containing plants are those types of biomass that include wood, agricultural residues, and paper wastes. Lignocellulose is composed of the biopolymers cellulose, hemicellulose, and lignin. Cellulose, a polymer of glucose, is the component in lignocellulose that has potential for the production of fuel-grade ethanol by direct fermentation of the glucose. However, enzymatic hydrolysis of lignocellulose and raw cellulose into glucose is hindered by the presence of lignin. The cellulase enzyme, which hydrolyzes cellulose to glucose, becomes irreversibly bound to lignin. This requires using the enzyme in reagent quantities rather than in catalytic concentration. The extensive use of this enzyme is expensive and adversely affects the economics of ethanol production. PureVision has approached this problem by developing a biomass fractionator to pretreat the lignocellulose to yield a highly pure cellulose fraction. The biomass fractionator is based on sequentially treating the biomass with hot water, hot alkaline solutions, and polishing the cellulose fraction with a wet alkaline oxidation step. In September 2001 PureVision and Western Research Institute (WRI) initiated a jointly sponsored research project with the U.S. Department of Energy (DOE) to evaluate their pretreatment technology, develop an understanding of the chemistry, and provide the data required to design and fabricate a one- to two-ton/day pilot-scale unit. The efforts during the first year of this program completed the design, fabrication, and shakedown of a bench-scale reactor system and evaluated the fractionation of corn stover. The results from the evaluation of corn stover have shown that water hydrolysis prior to

  17. Catalytic conversion of lignocellulosic biomass to fine chemicals and fuels.

    PubMed

    Zhou, Chun-Hui; Xia, Xi; Lin, Chun-Xiang; Tong, Dong-Shen; Beltramini, Jorge

    2011-11-01

    Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references). This journal is © The Royal Society of Chemistry 2011

  18. Co-hydrolysis of lignocellulosic biomass for microbial lipid accumulation.

    PubMed

    Ruan, Zhenhua; Zanotti, Michael; Zhong, Yuan; Liao, Wei; Ducey, Chad; Liu, Yan

    2013-04-01

    The herbaceous perennial energy crops miscanthus, giant reed, and switchgrass, along with the annual crop residue corn stover, were evaluated for their bioconversion potential. A co-hydrolysis process, which applied dilute acid pretreatment, directly followed by enzymatic saccharification without detoxification and liquid-solid separation between these two steps was implemented to convert lignocellulose into monomeric sugars (glucose and xylose). A factorial experiment in a randomized block design was employed to optimize the co-hydrolysis process. Under the optimal reaction conditions, corn stover exhibited the greatest total sugar yield (glucose + xylose) at 0.545 g g(-1) dry biomass at 83.3% of the theoretical yield, followed by switch grass (0.44 g g(-1) dry biomass, 65.8% of theoretical yield), giant reed (0.355 g g(-1) dry biomass, 64.7% of theoretical yield), and miscanthus (0.349 g g(-1) dry biomass, 58.1% of theoretical yield). The influence of combined severity factor on the susceptibility of pretreated substrates to enzymatic hydrolysis was clearly discernible, showing that co-hydrolysis is a technically feasible approach to release sugars from lignocellulosic biomass. The oleaginous fungus Mortierella isabellina was selected and applied to the co-hydrolysate mediums to accumulate fungal lipids due to its capability of utilizing both C5 and C6 sugars. Fungal cultivations grown on the co-hydrolysates exhibited comparable cell mass and lipid production to the synthetic medium with pure glucose and xylose. These results elucidated that combining fungal fermentation and co-hydrolysis to accumulate lipids could have the potential to enhance the utilization efficiency of lignocellulosic biomass for advanced biofuels production. Copyright © 2012 Wiley Periodicals, Inc.

  19. Enzyme Characterization of Cellulase and Hemicellulases Component Enzymes and Saccharification of Ionic Liquid Pretreated Lignocellulosic Biomass

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass is comprised of cellulose and hemicellulose, sources of polysaccharides, and lignin, a macromolecule with extensive aromaticity. Terrestrial biomass can provide a renewable carbon based feedstock for fuel and chemical production. However, recalcitrance of biomass to deconstru...

  20. Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization

    PubMed Central

    Alonso, David Martin; Hakim, Sikander H.; Zhou, Shengfei; Won, Wangyun; Hosseinaei, Omid; Tao, Jingming; Garcia-Negron, Valerie; Motagamwala, Ali Hussain; Mellmer, Max A.; Huang, Kefeng; Houtman, Carl J.; Labbé, Nicole; Harper, David P.; Maravelias, Christos T.; Runge, Troy; Dumesic, James A.

    2017-01-01

    The production of renewable chemicals and biofuels must be cost- and performance- competitive with petroleum-derived equivalents to be widely accepted by markets and society. We propose a biomass conversion strategy that maximizes the conversion of lignocellulosic biomass (up to 80% of the biomass to useful products) into high-value products that can be commercialized, providing the opportunity for successful translation to an economically viable commercial process. Our fractionation method preserves the value of all three primary components: (i) cellulose, which is converted into dissolving pulp for fibers and chemicals production; (ii) hemicellulose, which is converted into furfural (a building block chemical); and (iii) lignin, which is converted into carbon products (carbon foam, fibers, or battery anodes), together producing revenues of more than $500 per dry metric ton of biomass. Once de-risked, our technology can be extended to produce other renewable chemicals and biofuels. PMID:28560350

  1. Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization.

    PubMed

    Alonso, David Martin; Hakim, Sikander H; Zhou, Shengfei; Won, Wangyun; Hosseinaei, Omid; Tao, Jingming; Garcia-Negron, Valerie; Motagamwala, Ali Hussain; Mellmer, Max A; Huang, Kefeng; Houtman, Carl J; Labbé, Nicole; Harper, David P; Maravelias, Christos; Runge, Troy; Dumesic, James A

    2017-05-01

    The production of renewable chemicals and biofuels must be cost- and performance- competitive with petroleum-derived equivalents to be widely accepted by markets and society. We propose a biomass conversion strategy that maximizes the conversion of lignocellulosic biomass (up to 80% of the biomass to useful products) into high-value products that can be commercialized, providing the opportunity for successful translation to an economically viable commercial process. Our fractionation method preserves the value of all three primary components: (i) cellulose, which is converted into dissolving pulp for fibers and chemicals production; (ii) hemicellulose, which is converted into furfural (a building block chemical); and (iii) lignin, which is converted into carbon products (carbon foam, fibers, or battery anodes), together producing revenues of more than $500 per dry metric ton of biomass. Once de-risked, our technology can be extended to produce other renewable chemicals and biofuels.

  2. Harnessing the potential of ligninolytic enzymes for lignocellulosic biomass pretreatment.

    PubMed

    Masran, Ruqayyah; Zanirun, Zuraidah; Bahrin, Ezyana Kamal; Ibrahim, Mohamad Faizal; Lai Yee, Phang; Abd-Aziz, Suraini

    2016-06-01

    Abundant lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products such as biofuel, animal feed, and paper pulping. However, low yield of sugar obtained from lignocellulosic hydrolysate is usually due to the presence of lignin that acts as a protective barrier for cellulose and thus restricts the accessibility of the enzyme to work on the cellulosic component. This review focuses on the significance of biological pretreatment specifically using ligninolytic enzymes as an alternative method apart from the conventional physical and chemical pretreatment. Different modes of biological pretreatment are discussed in this paper which is based on (i) fungal pretreatment where fungi mycelia colonise and directly attack the substrate by releasing ligninolytic enzymes and (ii) enzymatic pretreatment using ligninolytic enzymes to counter the drawbacks of fungal pretreatment. This review also discusses the important factors of biological pretreatment using ligninolytic enzymes such as nature of the lignocellulosic biomass, pH, temperature, presence of mediator, oxygen, and surfactant during the biodelignification process.

  3. Chemical and physicochemical pretreatment of lignocellulosic biomass: a review.

    PubMed

    Brodeur, Gary; Yau, Elizabeth; Badal, Kimberly; Collier, John; Ramachandran, K B; Ramakrishnan, Subramanian

    2011-01-01

    Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility.

  4. Chemical and Physicochemical Pretreatment of Lignocellulosic Biomass: A Review

    PubMed Central

    Brodeur, Gary; Yau, Elizabeth; Badal, Kimberly; Collier, John; Ramachandran, K. B.; Ramakrishnan, Subramanian

    2011-01-01

    Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility. PMID:21687609

  5. Development of a commercial enzymes system for lignocellulosic biomass saccharification

    SciTech Connect

    Kumar, Manoj

    2012-12-20

    DSM Innovation Inc., in its four year effort was able to evaluate and develop its in-house DSM fungal cellulolytic enzymes system to reach enzyme efficiency mandates set by DoE Biomass program MYPP goals. DSM enzyme cocktail is uniquely active at high temperature and acidic pH, offering many benefits and product differentiation in 2G bioethanol production. Under this project, strain and process development, ratio optimization of enzymes, protein and genetic engineering has led to multitudes of improvement in productivity and efficiency making development of a commercial enzyme system for lignocellulosic biomass saccharification viable. DSM is continuing further improvement by additional biodiversity screening, protein engineering and overexpression of enzymes to continue to further lower the cost of enzymes for saccharification of biomass.

  6. Thermogravimetric-mass spectrometric analysis on combustion of lignocellulosic biomass.

    PubMed

    López-González, D; Fernandez-Lopez, M; Valverde, J L; Sanchez-Silva, L

    2013-09-01

    Combustion characteristics of biomass main components and three lignocellulosic biomass (fir wood, eucalyptus wood and pine bark) were investigated by thermogravimetric analysis coupled with mass spectrometry. The combustion of biomass was divided into two main steps, devolatilization and char oxidation stage. Heating rate effect was also studied. Generally, the higher the heating rate, the higher the decomposition temperature. Furthermore, the weight loss rate decreased due to particle temperature gradients. Combustion kinetics were studied. Models based on reaction order (Oi), nucleation (Ni) and diffusion (Di) achieved the best fitting to the experimental data. Cellulose oxidation presented the highest activation energies. CO, CO2 and H2O were the main components evolved from combustion. Additionally, light hydrocarbons (CH4 and C2H5) were also present. Finally, nitrogen compounds were in a higher proportion than sulfur compounds being released as primary amines and NOx. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Bioconversion of lignocellulosic biomass: biochemical and molecular perspectives.

    PubMed

    Kumar, Raj; Singh, Sompal; Singh, Om V

    2008-05-01

    In view of rising prices of crude oil due to increasing fuel demands, the need for alternative sources of bioenergy is expected to increase sharply in the coming years. Among potential alternative bioenergy resources, lignocellulosics have been identified as the prime source of biofuels and other value-added products. Lignocelluloses as agricultural, industrial and forest residuals account for the majority of the total biomass present in the world. To initiate the production of industrially important products from cellulosic biomass, bioconversion of the cellulosic components into fermentable sugars is necessary. A variety of microorganisms including bacteria and fungi may have the ability to degrade the cellulosic biomass to glucose monomers. Bacterial cellulases exist as discrete multi-enzyme complexes, called cellulosomes that consist of multiple subunits. Cellulolytic enzyme systems from the filamentous fungi, especially Trichoderma reesei, contain two exoglucanases or cellobiohydrolases (CBH1 and CBH2), at least four endoglucanases (EG1, EG2, EG3, EG5), and one beta-glucosidase. These enzymes act synergistically to catalyse the hydrolysis of cellulose. Different physical parameters such as pH, temperature, adsorption, chemical factors like nitrogen, phosphorus, presence of phenolic compounds and other inhibitors can critically influence the bioconversion of lignocellulose. The production of cellulases by microbial cells is governed by genetic and biochemical controls including induction, catabolite repression, or end product inhibition. Several efforts have been made to increase the production of cellulases through strain improvement by mutagenesis. Various physical and chemical methods have been used to develop bacterial and fungal strains producing higher amounts of cellulase, all with limited success. Cellulosic bioconversion is a complex process and requires the synergistic action of the three enzymatic components consisting of endoglucanases

  8. Development of a Commerical Enzyme System for Lignocellulosic Biomass Saccharification

    SciTech Connect

    Kumar, Manoj

    2011-02-14

    Lignocellulosic biomass is the most abundant, least expensive renewable natural biological resource for the production of biobased products and bioenergy is important for the sustainable development of human civilization in 21st century. For making the fermentable sugars from lignocellulosic biomass, a reduction in cellulase production cost, an improvement in cellulase performance, and an increase in sugar yields are all vital to reduce the processing costs of biorefineries. Improvements in specific cellulase activities for non-complexed cellulase mixtures can be implemented through cellulase engineering based on rational design or directed evolution for each cellulase component enzyme, as well as on the reconstitution of cellulase components. In this paper, we will provide DSM's efforts in cellulase research and developments and focus on limitations. Cellulase improvement strategies based on directed evolution using screening on relevant substrates, screening for higher thermal tolerance based on activity screening approaches such as continuous culture using insoluble cellulosic substrates as a powerful selection tool for enriching beneficial cellulase mutants from the large library. We will illustrate why and how thermostable cellulases are vital for economic delivery of bioproducts from cellulosic biomass using biochemical conversion approach.

  9. Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

    NASA Astrophysics Data System (ADS)

    Maddi, Balakrishna

    Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from

  10. Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate

    SciTech Connect

    Binder, Thomas; Erpelding, Michael; Schmid, Josef; Chin, Andrew; Sammons, Rhea; Rockafellow, Erin

    2015-04-10

    Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate. The purpose of Archer Daniels Midlands Integrated Biorefinery (IBR) was to demonstrate a modified acetosolv process on corn stover. It would show the fractionation of crop residue to distinct fractions of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions would be further converted to ethanol as the primary product and a fraction of the sugars would be catalytically converted to acrylic acid, with butyl acrylate the final product. These primary steps have been demonstrated.

  11. Calcium-catalyzed pyrolysis of lignocellulosic biomass components.

    PubMed

    Case, Paige A; Truong, Chi; Wheeler, M Clayton; DeSisto, William J

    2015-09-01

    The present study examines the effect of calcium pretreatment on pyrolysis of individual lignocellulosic compounds. Previous work has demonstrated that the incorporation of calcium compounds with the feedstock prior to pyrolysis has a significant effect on the oxygen content and stability of the resulting oil. The aim of this work was to further explore the chemistry of calcium-catalyzed pyrolysis. Bench-scale pyrolysis of biomass constituents, including lignin, cellulose and xylan is performed and compared to the oils produced from pyrolysis of the same components after calcium pretreatment. The resulting oils were analyzed by quantitative GC-MS and SEC. These analyses, together with data collected from previous work provide evidence which was used to develop proposed reaction pathways for pyrolysis of calcium-pretreatment biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A fundamental review of the relationships between nanotechnology and lignocellulosic biomass

    Treesearch

    Theodore Wegner; E. Philip Jones

    2009-01-01

    At first glance, the relationship between nanotechnology and lignocellulosic biomass may seem to be unconnected or at best tenuously connected. It is important to recognize that. at a fundamental level, lignocellulosic biomass is made up of nanometer-size constitutive building block units that provide valuable properties to wood and other types of renewable...

  13. Manipulation of plant architecture to enhance lignocellulosic biomass

    PubMed Central

    Stamm, Petra; Verma, Vivek; Ramamoorthy, Rengasamy; Kumar, Prakash P.

    2012-01-01

    Background Biofuels hold the promise to replace an appreciable proportion of fossil fuels. Not only do they emit significantly lower amounts of greenhouse gases, they are much closer to being ‘carbon neutral’, since the source plants utilize carbon dioxide for their growth. In particular, second-generation lignocellulosic biofuels from agricultural wastes and non-food crops such as switchgrass promise sustainability and avoid diverting food crops to fuel. Currently, available lignocellulosic biomass could yield sufficient bioethanol to replace ∼10 % of worldwide petroleum use. Increasing the biomass used for biofuel production and the yield of bioethanol will thus help meet global energy demands while significantly reducing greenhouse gas emissions. Scope We discuss the advantages of various biotechnological approaches to improve crops and highlight the contribution of genomics and functional genomics in this field. Current knowledge concerning plant hormones and their intermediates involved in the regulation of plant architecture is presented with a special focus on gibberellins and cytokinins, and their signalling intermediates. We highlight the potential of information gained from model plants such as Arabidopsis thaliana and rice (Oryza sativa) to accelerate improvement of fuel crops. PMID:23071897

  14. Production and characterization of lignocellulosic biomass-derived activated carbon.

    PubMed

    Namazi, A B; Jia, C Q; Allen, D G

    2010-01-01

    The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400-600 °C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m²/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400 °C was too low, 600 °C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area.

  15. A review on bioconversion of lignocellulosic biomass to H2: Key challenges and new insights.

    PubMed

    Ren, Nan-Qi; Zhao, Lei; Chen, Chuan; Guo, Wan-Qian; Cao, Guang-Li

    2016-09-01

    With the increasing energy crisis and rising concern over climate change, the development of clean alternative energy sources is of great importance. Biohydrogen produced from lignocellulosic biomass is a promising candidate, because of its positives such as readily available, no harmful emissions, environment friendly, efficient, and renewable. However, obstacles still exist to enable the commercialization of biological hydrogen production from lignocellulosic biomass. Thus the objective of this work is to provide update information about the recent progress on lignocellulosic hydrogen conversion via dark fermentation. In this review, the most important technologies associated with lignocellulosic hydrogen fermentation were covered. Firstly, pretreatment methods for better utilization of lignocellulosic biomass are presented, at the same time, hydrolysis methods assisting to achieve efficient hydrogen fermentation were discussed. Afterwards, issues related to bioprocesses for hydrogen production purposes were presented. Additionally, the paper gave challenges and new insights of lignocellulosic biohydrogen production.

  16. Physiochemical characterization of lignocellulosic biomass dissolution by flowthrough pretreatment

    DOE PAGES

    Yan, Lishi; Pu, Yunqiao; Bowden, Mark; ...

    2015-11-24

    In this study, comprehensive understanding of biomass solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of valorizing biomass to fermentable sugars and lignin for biofuels production. In this study, poplar wood was flowthrough pretreated by water-only or 0.05% (w/w) sulfuric acid at different temperatures (220–270 °C), flow rate (25 mL/min), and reaction times (8–90 min), resulting in significant disruption of the lignocellulosic biomass. Ion chromatography (IC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, and solid state cross-polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR)more » spectroscopy were applied to characterize the pretreated biomass whole slurries in order to reveal depolymerization as well as solubilization mechanism and identify unique dissolution structural features during these pretreatments. Results showed temperature-dependent cellulose decrystallization in flowthrough pretreatment. Crystalline cellulose was completely disrupted, and mostly converted to amorphous cellulose and oligomers by water-only operation at 270 °C for 10 min and by 0.05 wt % H2SO4 flowthrough pretreatment at 220 °C for 12 min. Flowthrough pretreatment with 0.05% (w/w) H2SO4 led to a greater disruption of structures in pretreated poplar at a lower temperature compared to water-only pretreatment.« less

  17. Biodiesel from lignocellulosic biomass--prospects and challenges.

    PubMed

    Yousuf, Abu

    2012-11-01

    Biodiesel can be a potential alternative to petroleum diesel, but its high production cost has impeded its commercialization in most parts of the world. One of the main drivers for the generation and use of biodiesel is energy security, because this fuel can be produced from locally available resources, thereby reducing the dependence on imported oil. Many countries are now trying to produce biodiesel from plant or vegetable oils. However, the consumption of large amounts of vegetable oils for biodiesel production could result in a shortage in edible oils and cause food prices to soar. Alternatively, the use of animal fat, used frying oils, and waste oils from restaurants as feedstock could be a good strategy to reduce the cost. However, these limited resources might not meet the increasing demand for clean, renewable fuels. Therefore, recent research has been focused the use of residual materials as renewable feedstock in order to lower the cost of producing biodiesel. Microbial oils or single cell oils (SCOs), produced by oleaginous microorganisms have been studied as promising alternatives to vegetable or seed oils. Various types of agro-industrial residues have been suggested as prospective nutritional sources for microbial cultures. Since the most abundant residue from agricultural crops is lignocellulosic biomass (LCB), this byproduct has been given top-priority consideration as a source of biomass for producing biodiesel. But the biological transformation of lignocellulosic materials is complicated due to their crystalline structure. So, pretreatment is required before they can be converted into fermentable sugar. This article compares and scrutinizes the extent to which various microbes can accumulate high levels of lipids as functions of the starting materials and the fermentation conditions. Also, the obstacles associated with the use of LCB are described, along with a potentially viable approach for overcoming the obstacles that currently preclude the

  18. Enzymatic hydrolysis of lignocellulosic biomass from Onopordum nervosum.

    PubMed

    Martín, C; Negro, M J; Alfonsel, M; Sáez, R

    1988-07-20

    Some properties of the cellulolytic complex obtained from Trichoderma reesei QM 9414 grown on Solka floc as carbon source and its ability to hydrolyze the lignocellulosic biomass of Onopordum nervosum Boiss were studied. The optimum enzyme activity was found at temperatures between 50 and 55 degrees C and pH ranging from 4.3 to 4.8. Hydrolysis of 4-nitropnenyl-beta-D-glucopyranoside (4-NPG) and cellobiose by the beta-glucosidase of the complex, showed competitive inhibition by glucose with a K(i) value of 0.8 mM for 4-NPG and 2. 56 mM for cellobiose. Enzymatic hydrolysis yield of Onopordum nervosum, evaluated as glucose production after 48 h, showed a threefold increase by pretreating the lignocellulosic substrate with alkali. When the loss of glucose incurred by de pretreatment was taken into account, a 160% increase in the final cellulose to glucose conversion was found to be due to the pretreatment.

  19. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

    SciTech Connect

    Alcantara, Maria Angeles Bermudez; Azadi, Parastoo; Garcia, Bruno Diez; Reyes-Sosa, Francisco Manuel

    2016-10-06

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

  20. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

    DOE PAGES

    Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo; ...

    2016-10-06

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

  1. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass.

    PubMed

    Alcántara, María Ángeles Bermúdez; Dobruchowska, Justyna; Azadi, Parastoo; García, Bruno Díez; Molina-Heredia, Fernando P; Reyes-Sosa, Francisco Manuel

    2016-01-01

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. Two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. This suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

  2. Bioethanol from Lignocellulosic Biomass: Current Findings Determine Research Priorities

    PubMed Central

    Kang, Qian; Appels, Lise; Tan, Tianwei

    2014-01-01

    “Second generation” bioethanol, with lignocellulose material as feedstock, is a promising alternative for first generation bioethanol. This paper provides an overview of the current status and reveals the bottlenecks that hamper its implementation. The current literature specifies a conversion of biomass to bioethanol of 30 to ~50% only. Novel processes increase the conversion yield to about 92% of the theoretical yield. New combined processes reduce both the number of operational steps and the production of inhibitors. Recent advances in genetically engineered microorganisms are promising for higher alcohol tolerance and conversion efficiency. By combining advanced systems and by intensive additional research to eliminate current bottlenecks, second generation bioethanol could surpass the traditional first generation processes. PMID:25614881

  3. Epidemic based modeling of enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Tai, Chao; Arellano, Maria G; Keshwani, Deepak R

    2014-01-01

    An epidemic based model was developed to describe the enzymatic hydrolysis of a lignocellulosic biomass, dilute sulfuric acid pretreated corn stover. The process of substrate getting adsorbed and digested by enzyme was simulated as susceptibles getting infected by viruses and becoming removed and recovered. This model simplified the dynamic enzyme "infection" process and the catalysis of cellulose into a two-parameter controlled, enzyme behavior guided mechanism. Furthermore, the model incorporates the adsorption block by lignin and inhibition effects on cellulose catalysis. The model satisfactorily predicted the enzyme adsorption and hydrolysis, negative role of lignin, and inhibition effects over hydrolysis for a broad range of substrate and enzyme loadings. Sensitivity analysis was performed to evaluate the incorporation of lignin and other inhibition effects. Our model will be a useful tool for evaluating the effects of parameters during hydrolysis and guide a design strategy for continuous hydrolysis and the associated process control.

  4. Production of nanocrystalline cellulose from lignocellulosic biomass: technology and applications.

    PubMed

    Brinchi, L; Cotana, F; Fortunati, E; Kenny, J M

    2013-04-15

    The use of renewables materials for industrial applications is becoming impellent due to the increasing demand of alternatives to scarce and unrenewable petroleum supplies. In this regard, nanocrystalline cellulose, NCC, derived from cellulose, the most abundant biopolymer, is one of the most promising materials. NCC has unique features, interesting for the development of new materials: the abundance of the source cellulose, its renewability and environmentally benign nature, its mechanical properties and its nano-scaled dimensions open a wide range of possible properties to be discovered. One of the most promising uses of NCC is in polymer matrix nanocomposites, because it can provide a significant reinforcement. This review provides an overview on this emerging nanomaterial, focusing on extraction procedures, especially from lignocellulosic biomass, and on technological developments and applications of NCC-based materials. Challenges and future opportunities of NCC-based materials will be are discussed as well as obstacles remaining for their large use.

  5. Facile pretreatment of lignocellulosic biomass using deep eutectic solvents.

    PubMed

    Zhang, Cheng-Wu; Xia, Shu-Qian; Ma, Pei-Sheng

    2016-11-01

    In this work, three kinds of deep eutectic solvents (DESs) were facilely prepared and used in the pretreatment of corncob, including monocarboxylic acid/choline chloride, dicarboxylic acid/choline chloride and polyalcohol/choline chloride. The enhanced delignification and subsequent enzymatic hydrolysis efficiency were found to be related to the acid amount, acid strength and the nature of hydrogen bond acceptors. The XRD, SEM and FT-IR results consistently indicated that the structures of corncob were disrupted by the removal of lignin and hemicellulose in the pretreatment process. In addition, the optimal pretreatment temperature and time were 90°C and 24h, respectively. This study explored the roles of various DESs combinations, pretreatment temperature and time to better utilize the DESs in the pretreatment of lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

    PubMed Central

    Balan, Venkatesh

    2014-01-01

    Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be produced in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected. PMID:25937989

  7. Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

    DOE PAGES

    Balan, Venkatesh

    2014-01-01

    Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be producedmore » in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected.« less

  8. Laccase production by Aspergillus heteromorphus using distillery spent wash and lignocellulosic biomass.

    PubMed

    Singh, Anita; Bajar, Somvir; Bishnoi, Narsi R; Singh, Namita

    2010-04-15

    Laccase is among the major enzymes which plays an important role in ligninolytic system of fungi. Laccase production by Aspergillus heteromorphus was studied using anaerobically treated distillery spent wash (ADSW) and lignocellulosic biomass. Lignocellulosic biomass (rice straw, wheat straw and sugarcane bagasse) generated during biomass processing leads to solid waste and distillery spent wash is unwanted liquid waste produced by distilleries, both causes environmental pollution. Two mineral media and anaerobically treated distillery spent wash medium was tested for laccase production. Enzyme production in various media and in presence and absence of lignocellulosic biomass supplements showed that anaerobically treated distillery spent wash medium was a better laccase inducer medium than the mineral media. Addition of lignocellulosic biomass enhances laccase production and highest laccase activity was obtained in 5% anaerobically treated distillery spent wash medium with rice straw.

  9. Quantitative proteomic analysis of lignocellulolytic enzymes by Phanerochaete chrysosporium on different lignocellulosic biomass.

    PubMed

    Adav, Sunil S; Ravindran, Anita; Sze, Siu Kwan

    2012-02-16

    Lignocellulosic biomass from agricultural crop residues and forest waste represents an abundant renewable resource for bioenergy and future biofuel. The current bottleneck of lignocellulosic biofuel production is the hydrolysis of biomass to sugar. To understand the enzymatic hydrolysis of complex biomasses, in this report, lignocellulolytic enzymes secretion by Phanerochaete chrysosporium cultivated in different natural lignocellulosic biomass such as corn stover, hay, sawdust, sugarcane baggase, wheat bran and wood chips were quantitatively analyzed with the iTRAQ technique using LC-MS/MS. A diverse groups of enzymes, including cellulases, glycoside hydrolases, hemicellulases, lignin degrading enzymes, peroxidases, esterases, lipases, chitinases, peptidases, protein translocating transporter and hypothetical proteins were quantified, of which several were novel lignocellulosic biomass hydrolyzing enzymes. The quantitative expression and regulation of lignocellulolytic enzymes by P. chrysosporium were dependent on the nature and complexity of lignocellulosic biomass as well as physical size of the biomass. The iTRAQ data revealed oxidative and hydrolytic lignin degrading mechanism of P. chrysosporium. Numerous proteins presumed to be involved in natural lignocellulosic biomass transformation and degradation were expressed and produced in variable quantities in response to different agricultural and forest wastes. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Physiochemical characterization of lignocellulosic biomass dissolution by flowthrough pretreatment

    SciTech Connect

    Yan, Lishi; Pu, Yunqiao; Bowden, Mark; Ragauskas, Arthur J.; Yang, Bin

    2015-11-24

    In this study, comprehensive understanding of biomass solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of valorizing biomass to fermentable sugars and lignin for biofuels production. In this study, poplar wood was flowthrough pretreated by water-only or 0.05% (w/w) sulfuric acid at different temperatures (220–270 °C), flow rate (25 mL/min), and reaction times (8–90 min), resulting in significant disruption of the lignocellulosic biomass. Ion chromatography (IC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, and solid state cross-polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) spectroscopy were applied to characterize the pretreated biomass whole slurries in order to reveal depolymerization as well as solubilization mechanism and identify unique dissolution structural features during these pretreatments. Results showed temperature-dependent cellulose decrystallization in flowthrough pretreatment. Crystalline cellulose was completely disrupted, and mostly converted to amorphous cellulose and oligomers by water-only operation at 270 °C for 10 min and by 0.05 wt % H2SO4 flowthrough pretreatment at 220 °C for 12 min. Flowthrough pretreatment with 0.05% (w/w) H2SO4 led to a greater disruption of structures in pretreated poplar at a lower temperature compared to water-only pretreatment.

  11. Comparative study of pyrolysis of algal biomass from natural lake blooms with lignocellulosic biomass.

    PubMed

    Maddi, Balakrishna; Viamajala, Sridhar; Varanasi, Sasidhar

    2011-12-01

    Pyrolysis experiments were performed with algal and lignocellulosic feedstocks under similar reactor conditions for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from protein degradation). Algal bio-char also had a significantly higher N-content. Overall, our results suggest that it is feasible to convert algal cultures deficient in lipids, such as nuisance algae obtained from natural blooms, into liquid fuels by thermochemical methods. As such, pyrolysis technologies being developed for lignocellulosic biomass may be directly applicable to algal feedstocks as well.

  12. Pretreatment of Lignocellulosic Biomass with Ionic Liquids and Ionic Liquid-Based Solvent Systems.

    PubMed

    Hou, Qidong; Ju, Meiting; Li, Weizun; Liu, Le; Chen, Yu; Yang, Qian

    2017-03-20

    Pretreatment is very important for the efficient production of value-added products from lignocellulosic biomass. However, traditional pretreatment methods have several disadvantages, including low efficiency and high pollution. This article gives an overview on the applications of ionic liquids (ILs) and IL-based solvent systems in the pretreatment of lignocellulosic biomass. It is divided into three parts: the first deals with the dissolution of biomass in ILs and IL-based solvent systems; the second focuses on the fractionation of biomass using ILs and IL-based solvent systems as solvents; the third emphasizes the enzymatic saccharification of biomass after pretreatment with ILs and IL-based solvent systems.

  13. Autohydrolysis Pretreatment of Lignocellulosic Biomass for Bioethanol Production

    NASA Astrophysics Data System (ADS)

    Han, Qiang

    Autohydrolysis, a simple and environmental friendly process, has long been studied but often abandoned as a financially viable pretreatment for bioethanol production due to the low yields of fermentable sugars at economic enzyme dosages. The introduction of mechanical refining can generate substantial improvements for autohydrolysis process, making it an attractive pretreatment technology for bioethanol commercialization. In this study, several lignocellulosic biomass including wheat straw, switchgrass, corn stover, waste wheat straw have been subjected to autohydrolysis pretreatment followed by mechanical refining to evaluate the total sugar recovery at affordable enzyme dosages. Encouraging results have been found that using autohydrolysis plus refining strategy, the total sugar recovery of most feedstock can be as high as 76% at 4 FPU/g enzymes dosages. The mechanical refining contributed to the improvement of enzymatic sugar yield by as much as 30%. Three non-woody biomass (sugarcane bagasse, wheat straw, and switchgrass) and three woody biomass (maple, sweet gum, and nitens) have been subjected to autohydrolysis pretreatment to acquire a fundamental understanding of biomass characteristics that affect the autohydrolysis and the following enzymatic hydrolysis. It is of interest to note that the nonwoody biomass went through substantial delignification during autohydrolysis compared to woody biomass due to a significant amount of p-coumaric acid and ferulic acid. It has been found that hardwood which has a higher S/V ratio in the lignin structure tends to have a higher total sugar recovery from autohydrolysis pretreatment. The economics of bioethanol production from autohydrolysis of different feedstocks have been investigated. Regardless of different feedstocks, in the conventional design, producing bioethanol and co-producing steam and power, the minimum ethanol revenues (MER) required to generate a 12% internal rate of return (IRR) are high enough to

  14. Evolutionarily Engineered Ethanologenic Yeast Detoxifies Lignocellulosic Biomass Conversion Inhibitors by Reprogrammed Pathways

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass conversion inhibitors furfural and HMF inhibit microbial growth and interfere with subsequent fermentation of ethanol, posing significant challenges for a sustainable cellulosic ethanol conversion industry. Numerous yeast genes were found to be associated with the inhibitor ...

  15. Deconstruction of ionic liquid pretreated lignocellulosic biomass using mono-component cellulases and hemicellulases and commercial mixtures

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass is comprised of cellulose and hemicellulose, sources of polysaccharides, and lignin, a macromolecule with extensive aromaticity. Lignocellulose requires pretreatment before biochemical conversion to its monomeric sugars which can provide a renewable carbon based feedstock for...

  16. Lignocellulosic Biomass Derived Functional Materials: Synthesis and Applications in Biomedical Engineering.

    PubMed

    Zhang, Lei; Peng, Xinwen; Zhong, Linxin; Chua, Weitian; Xiang, Zhihua; Sun, Runcang

    2017-09-18

    The pertinent issue of resources shortage arising from global climate change in the recent years has accentuated the importance of materials that are environmental friendly. Despite the merits of current material like cellulose as the most abundant natural polysaccharide on earth, the incorporation of lignocellulosic biomass has the potential to value-add the recent development of cellulose-derivatives in drug delivery systems. Lignocellulosic biomass, with a hierarchical structure, comprised of cellulose, hemicellulose and lignin. As an excellent substrate that is renewable, biodegradable, biocompatible and chemically accessible for modified materials, lignocellulosic biomass sets forth a myriad of applications. To date, materials derived from lignocellulosic biomass have been extensively explored for new technological development and applications, such as biomedical, green electronics and energy products. In this review, chemical constituents of lignocellulosic biomass are first discussed before we critically examine the potential alternatives in the field of biomedical application. In addition, the pretreatment methods for extracting cellulose, hemicellulose and lignin from lignocellulosic biomass as well as their biological applications including drug delivery, biosensor, tissue engineering etc will be reviewed. It is anticipated there will be an increasing interest and research findings in cellulose, hemicellulose and lignin from natural resources, which help provide important directions for the development in biomedical applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Validation of lignocellulosic biomass carbohydrates determination via acid hydrolysis.

    PubMed

    Zhou, Shengfei; Runge, Troy M

    2014-11-04

    This work studied the two-step acid hydrolysis for determining carbohydrates in lignocellulosic biomass. Estimation of sugar loss based on acid hydrolyzed sugar standards or analysis of sugar derivatives was investigated. Four model substrates (starch, holocellulose, filter paper and cotton) and three levels of acid/material ratios (7.8, 10.3 and 15.4, v/w) were studied to demonstrate the range of test artifacts. The method for carbohydrates estimation based on acid hydrolyzed sugar standards having the most satisfactory carbohydrate recovery and relative standard deviation. Raw material and the acid/material ratio both had significant effect on carbohydrate hydrolysis, suggesting the acid to have impacts beyond a catalyst in the hydrolysis. Following optimal procedures, we were able to reach a carbohydrate recovery of 96% with a relative standard deviation less than 3%. The carbohydrates recovery lower than 100% was likely due to the incomplete hydrolysis of substrates, which was supported by scanning electron microscope (SEM) images. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Soluble inhibitors/deactivators of cellulase enzymes from lignocellulosic biomass.

    PubMed

    Kim, Youngmi; Ximenes, Eduardo; Mosier, Nathan S; Ladisch, Michael R

    2011-04-07

    Liquid hot water, steam explosion, and dilute acid pretreatments of lignocellulose generate soluble inhibitors which hamper enzymatic hydrolysis as well as fermentation of sugars to ethanol. Toxic and inhibitory compounds will vary with pretreatment and include soluble sugars, furan derivatives (hydroxymethyl fulfural, furfural), organic acids (acetic, formic and, levulinic acid), and phenolic compounds. Their effect is seen when an increase in the concentration of pretreated biomass in a hydrolysis slurry results in decreased cellulose conversion, even though the ratio of enzyme to cellulose is kept constant. We used lignin-free cellulose, Solka Floc, combined with mixtures of soluble components released during pretreatment of wood, to prove that the decrease in the rate and extent of cellulose hydrolysis is due to a combination of enzyme inhibition and deactivation. The causative agents were extracted from wood pretreatment liquid using PEG surfactant, activated charcoal or ethyl acetate and then desorbed, recovered, and added back to a mixture of enzyme and cellulose. At enzyme loadings of either 1 or 25mg protein/g glucan, the most inhibitory components, later identified as phenolics, decreased the rate and extent of cellulose hydrolysis by half due to both inhibition and precipitation of the enzymes. Full enzyme activity occurred when the phenols were removed. Hence detoxification of pretreated woods through phenol removal is expected to reduce enzyme loadings, and therefore reduce enzyme costs, for a given level of cellulose conversion. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Application of next-generation sequencing methods for microbial monitoring of anaerobic digestion of lignocellulosic biomass.

    PubMed

    Bozan, Mahir; Akyol, Çağrı; Ince, Orhan; Aydin, Sevcan; Ince, Bahar

    2017-08-04

    The anaerobic digestion of lignocellulosic wastes is considered an efficient method for managing the world's energy shortages and resolving contemporary environmental problems. However, the recalcitrance of lignocellulosic biomass represents a barrier to maximizing biogas production. The purpose of this review is to examine the extent to which sequencing methods can be employed to monitor such biofuel conversion processes. From a microbial perspective, we present a detailed insight into anaerobic digesters that utilize lignocellulosic biomass and discuss some benefits and disadvantages associated with the microbial sequencing techniques that are typically applied. We further evaluate the extent to which a hybrid approach incorporating a variation of existing methods can be utilized to develop a more in-depth understanding of microbial communities. It is hoped that this deeper knowledge will enhance the reliability and extent of research findings with the end objective of improving the stability of anaerobic digesters that manage lignocellulosic biomass.

  20. Factors governing dissolution process of lignocellulosic biomass in ionic liquid: current status, overview and challenges.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2015-02-01

    The utilisation of non-feed lignocellulosic biomass as a source of renewable bio-energy and synthesis of fine chemical products is necessary for the sustainable development. The methods for the dissolution of lignocellulosic biomass in conventional solvents are complex and tedious due to the complex chemical ultra-structure of biomass. In view of this, recent developments for the use of ionic liquid solvent (IL) has received great attention, as ILs can solubilise such complex biomass and thus provides industrial scale-up potential. In this review, we have discussed the state-of-art for the dissolution of lignocellulosic material in representative ILs. Furthermore, various process parameters and their influence for biomass dissolution were reviewed. In addition to this, overview of challenges and opportunities related to this interesting area is presented.

  1. Recent Advances in the Application of Inorganic Salt Pretreatment for Transforming Lignocellulosic Biomass into Reducing Sugars.

    PubMed

    Loow, Yu-Loong; Wu, Ta Yeong; Tan, Khang Aik; Lim, Yung Shen; Siow, Lee Fong; Jahim, Jamaliah Md; Mohammad, Abdul Wahab; Teoh, Wen Hui

    2015-09-30

    Currently, the transformation of lignocellulosic biomass into value-added products such as reducing sugars is garnering attention worldwide. However, efficient hydrolysis is usually hindered by the recalcitrant structure of the biomass. Many pretreatment technologies have been developed to overcome the recalcitrance of lignocellulose such that the components can be reutilized more effectively to enhance sugar recovery. Among all of the utilized pretreatment methods, inorganic salt pretreatment represents a more novel method and offers comparable sugar recovery with the potential for reducing costs. The use of inorganic salt also shows improved performance when it is integrated with other pretreatment technologies. Hence, this paper is aimed to provide a detailed overview of the current situation for lignocellulosic biomass and its physicochemical characteristics. Furthermore, this review discusses some recent studies using inorganic salt for pretreating biomass and the mechanisms involved during the process. Finally, some prospects and challenges using inorganic salt are highlighted.

  2. Organic solvent pretreatment of lignocellulosic biomass for biofuels and biochemicals: A review.

    PubMed

    Zhang, Ke; Pei, Zhijian; Wang, Donghai

    2016-01-01

    Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Pretreatment is an essential component of biomass conversion process, affecting a majority of downstream processes, including enzymatic hydrolysis, fermentation, and final product separation. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Objectives of this review were to update and extend previous works on pretreatment of lignocellulosic biomass for biofuels and biochemicals using organic solvents, especially on ethanol, methanol, ethylene glycol, glycerol, acetic acid, and formic acid. Perspectives and recommendations were given to fully describe implementation of proper organic solvent pretreatment for future research.

  3. Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol

    SciTech Connect

    2011-05-02

    The U.S. Department of Energy (DOE) promotes the production of ethanol and other liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in the program, the National Renewable Energy Laboratory (NREL) investigates the production economics of these fuels.

  4. Sonochemistry: what potential for conversion of lignocellulosic biomass into platform chemicals?

    PubMed

    Chatel, Gregory; De Oliveira Vigier, Karine; Jérôme, François

    2014-10-01

    This Review focuses on the use of ultrasound to produce chemicals from lignocellulosic biomass. However, the question about the potential of sonochemistry for valorization/conversion of lignocellulosic biomass into added-value chemicals is rather conceptual. Until now, this technology has been mainly used for the production of low-value chemicals such as biodiesel or as simple method for pretreatment or extraction. According to preliminary studies reported in literature, access to added-value chemicals can be easily and sometimes solely obtained by the use of ultrasound. The design of sonochemical parameters offers many opportunities to develop new eco-friendly and efficient processes. The goal of this Review is to understand why the use of ultrasound is focused rather on pretreatment or extraction of lignocellulosic biomass rather than on the production of chemicals and to understand, through the reported examples, which directions need to be followed to favor strategies based on ultrasound-assisted production of chemicals from lignocellulosic biomass. We believe that ultrasound-assisted processes represent an innovative approach and will create a growing interest in academia but also in the industry in the near future. Based on the examples reported in the literature, we critically discuss how sonochemistry could offer new strategies and give rise to new results in lignocellulosic biomass valorization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Development of biocatalysts for production of commodity chemicals from lignocellulosic biomass.

    PubMed

    Adsul, M G; Singhvi, M S; Gaikaiwari, S A; Gokhale, D V

    2011-03-01

    Lignocellulosic biomass is recognized as potential sustainable source for production of power, biofuels and variety of commodity chemicals which would potentially add economic value to biomass. Recalcitrance nature of biomass is largely responsible for the high cost of its conversion. Therefore, it is necessary to introduce some cost effective pretreatment processes to make the biomass polysaccharides easily amenable to enzymatic attack to release mixed fermentable sugars. Advancement in systemic biology can provide new tools for the development of such biocatalysts for sustainable production of commodity chemicals from biomass. Integration of functional genomics and system biology approaches may generate efficient microbial systems with new metabolic routes for production of commodity chemicals. This paper provides an overview of the challenges that are faced by the processes converting lignocellulosic biomass to commodity chemicals. The critical factors involved in engineering new microbial biocatalysts are also discussed with more emphasis on commodity chemicals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Simultaneous Saccharification and Fermentation and Partial Saccharification and Co-fermentation of Lignocellulosic Biomass for Ethanol Production

    USDA-ARS?s Scientific Manuscript database

    Ethanol production by fermentation of lignocellulosic biomass-derived sugars involves a fairly ancient art and an ever-evolving science. Production of ethanol from lignocellulosic biomass is not avant-grade and wood ethanol plants have been in existence since at least 1915. Most current ethanol pr...

  7. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    PubMed

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  8. A Comparative Study of Dilute acid and Ionic Liquid Pretreatment of Biomass and Model Lignocellulosics

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass has the great potential to serve as the low cost and abundant feedstock for bioconversion into fermentable sugars, which can be further utilized for biofuel production. However, high lignin content, crystalline cellulose structure and the presence of ester linkages between l...

  9. Nanostructured enzyme assemblies for lignocellulosic biomass breakdown for bioproduct and bioenergy applications

    USDA-ARS?s Scientific Manuscript database

    The continued reliance on fossil fuels to supply our chemical feedstock and energy requirements is unsustainable. However, it is estimated that there are greater than 220 billion tons of lignocellulosic biomass available globally which represents a tremendous renewable source for society’s chemical...

  10. Ethanol production from lignocellulosic biomass by recombinant Escherichia coli strain FBR5

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass, upon pretreatment and enzymatic hydrolysis, generates a mixture of hexose and pentose sugars such as glucose, xylose, arabinose and galactose. Escherichia coli utilizes all these sugars well but it lacks the ability to produce ethanol from them. Recombinant ethanologenic E...

  11. Conceptual net energy output for biofuel production from lignocellulosic biomass through biorefining

    Treesearch

    J.Y. Zhu; X.S. Zhuang

    2012-01-01

    There is a lack of comprehensive information in the retrievable literature on pilot scale process and energy data using promising process technologies and commercially scalable and available capital equipment for lignocellulosic biomass biorefining. This study conducted a comprehensive review of the energy efficiency of selected sugar platform biorefinery process...

  12. Atomistic Simulation of Lignocellulosic Biomass and Associated Cellulosomal Protein Complexes

    SciTech Connect

    Petridis, Loukas; Crowley, Michael F; Smith, Jeremy C

    2010-01-01

    Computer simulations have been performed to obtain an atomic-level understanding of lignocellulose structure and the assembly of its associated cellulosomal protein complexes. First, a CHARMM molecular mechanics force field for lignin is derived and validated by performing a molecular dynamics simulation of a crystal of a lignin fragment molecule and comparing simulation-derived structural features with experimental results. Together with the existing force field for polysaccharides, this work provides the basis for full simulations of lignocellulose. Second, the underlying molecular mechanism governing the assembly of various cellulosomal modules is investigated by performing a novel free-energy calculation of the cohesin-dockerin dissociation. Our calculation indicates a free-energy barrier of ~17 kcal/mol and further reveals a stepwise dissociation pathway involving both the central -sheet interface and its adjacent solvent-exposed loop/turn regions clustered at both ends of the -barrel structure.

  13. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR.

    PubMed

    Fu, Li; McCallum, Scott A; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J; Zhang, Fuming; Linhardt, Robert J

    2015-02-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of (13)C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment.

  14. Process design and evaluation of production of bioethanol and β-lactam antibiotic from lignocellulosic biomass.

    PubMed

    Kim, Sung Bong; Park, Chulhwan; Kim, Seung Wook

    2014-11-01

    To design biorefinery processes producing bioethanol from lignocellulosic biomass with dilute acid pretreatment, biorefinery processes were simulated using the SuperPro Designer program. To improve the efficiency of biomass use and the economics of biorefinery, additional pretreatment processes were designed and evaluated, in which a combined process of dilute acid and aqueous ammonia pretreatments, and a process of waste media containing xylose were used, for the production of 7-aminocephalosporanic acid. Finally, the productivity and economics of the designed processes were compared.

  15. Biofuels and biomass-to-liquid fuels in the biorefinery: catalytic conversion of lignocellulosic biomass using porous materials.

    PubMed

    Stöcker, Michael

    2008-01-01

    At a time when the focus is on global warming, CO(2) emission, secure energy supply, and less consumption of fossil-based fuels, the use of renewable energy resources is essential. Various biomass resources are discussed that can deliver fuels, chemicals, and energy products. The focus is on the catalytic conversion of biomass from wood. The challenges involved in the processing of lignocellulose-rich materials will be highlighted, along with the application of porous materials as catalysts for the biomass-to-liquids (BTL) fuels in biorefineries. The mechanistic understanding of the complex reactions that take place, the development of catalysts and processes, and the product spectrum that is envisaged will be discussed, along with a sustainable concept for biorefineries based on lignocellulose. Finally, the current situation with respect to upgrading of the process technology (pilot and commercial units) will be addressed.

  16. Enzymatic hydrolysis and characterization of lignocellulosic biomass exposed to electron beam irradiation.

    PubMed

    Karthika, K; Arun, A B; Rekha, P D

    2012-10-01

    Pretreatment of lignocellulosic biomass has been taken up as a global challenge as it comprises a large renewable source of fermentable sugars. In this study, effect of electron beam irradiation (EBI) on a hybrid grass variety investigated as a biomass pretreatment method. Dry biomass samples after characterization were exposed to EBI doses of 0, 75, 150 and 250 kGy. The pretreated biomass samples were enzymatically hydrolyzed using Trichoderma reesei ATCC 26921 cellulase for 144 h. The enzyme loadings were 15 and 30 FPU/g of biomass. The structural changes and degree of crystallinity of the pretreated biomass were studied by FTIR, XRD and SEM analyses. The lignocellulosic biomass sample showed 12.0% extractives, 36.9% cellulose, 28.4% hemicellulose, 11.9% lignin and 8.6% ash. Significant improvements in the reducing sugar and glucose yields were observed in the hydrolysate of EBI pretreated biomass compared to the control. In 250 kGy exposed samples 79% of the final reducing sugar yield was released within 48 h of hydrolysis at an enzyme loading rate of 30FPU/g of biomass. The IR crystallinity index calculated from the FTIR data and degree of crystallinity (XRD) decreased in the EBI treated samples. A significant negative correlation was observed between degree of crystallinity and the glucose yield from enzymatic hydrolysis.

  17. Overcoming Biomass Recalcitrance by Combining Genetically Modified Switchgrass and Cellulose Solvent-Based Lignocellulose Pretreatment

    PubMed Central

    Zhao, Bingyu; Zhang, Y.-H. Percival

    2013-01-01

    Decreasing lignin content of plant biomass by genetic engineering is believed to mitigate biomass recalcitrance and improve saccharification efficiency of plant biomass. In this study, we compared two different pretreatment methods (i.e., dilute acid and cellulose solvent) on transgenic plant biomass samples having different lignin contents and investigated biomass saccharification efficiency. Without pretreatment, no correlation was observed between lignin contents of plant biomass and saccharification efficiency. After dilute acid pretreatment, a strong negative correlation between lignin content of plant samples and overall glucose release was observed, wherein the highest overall enzymatic glucan digestibility was 70% for the low-lignin sample. After cellulose solvent- and organic solvent-based lignocellulose fractionation pretreatment, there was no strong correlation between lignin contents and high saccharification efficiencies obtained (i.e., 80–90%). These results suggest that the importance of decreasing lignin content in plant biomass to saccharification was largely dependent on pretreatment choice and conditions. PMID:24086283

  18. Surface properties correlate to the digestibility of hydrothermally pretreated lignocellulosic Poaceae biomass feedstocks.

    PubMed

    Djajadi, Demi T; Hansen, Aleksander R; Jensen, Anders; Thygesen, Lisbeth G; Pinelo, Manuel; Meyer, Anne S; Jørgensen, Henning

    2017-01-01

    Understanding factors that govern lignocellulosic biomass recalcitrance is a prerequisite for designing efficient 2nd generation biorefining processes. However, the reasons and mechanisms responsible for quantitative differences in enzymatic digestibility of various biomass feedstocks in response to hydrothermal pretreatment at different severities are still not sufficiently understood. Potentially important lignocellulosic feedstocks for biorefining, corn stover (Zea mays subsp. mays L.), stalks of Miscanthus × giganteus, and wheat straw (Triticum aestivum L.) were systematically hydrothermally pretreated; each at three different severities of 3.65, 3.83, and 3.97, respectively, and the enzymatic digestibility was assessed. Pretreated samples of Miscanthus × giganteus stalks were the least digestible among the biomass feedstocks producing ~24 to 66.6% lower glucose yields than the other feedstocks depending on pretreatment severity and enzyme dosage. Bulk biomass composition analyses, 2D nuclear magnetic resonance, and comprehensive microarray polymer profiling were not able to explain the observed differences in recalcitrance among the pretreated feedstocks. However, methods characterizing physical and chemical features of the biomass surfaces, specifically contact angle measurements (wettability) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy (surface biopolymer composition) produced data correlating pretreatment severity and enzymatic digestibility, and they also revealed differences that correlated to enzymatic glucose yield responses among the three different biomass types. The study revealed that to a large extent, factors related to physico-chemical surface properties, namely surface wettability as assessed by contact angle measurements and surface content of hemicellulose, lignin, and wax as assessed by ATR-FTIR rather than bulk biomass chemical composition correlated to the recalcitrance of the tested biomass

  19. Discovery of genes coding for carbohydrate-active enzyme by metagenomic analysis of lignocellulosic biomasses

    PubMed Central

    Montella, Salvatore; Ventorino, Valeria; Lombard, Vincent; Henrissat, Bernard; Pepe, Olimpia; Faraco, Vincenza

    2017-01-01

    In this study, a high-throughput sequencing approach was applied to discover novel biocatalysts for lignocellulose hydrolysis from three dedicated energy crops, Arundo donax, Eucalyptus camaldulensis and Populus nigra, after natural biodegradation. The microbiomes of the three lignocellulosic biomasses were dominated by bacterial species (approximately 90%) with the highest representation by the Streptomyces genus both in the total microbial community composition and in the microbial diversity related to GH families of predicted ORFs. Moreover, the functional clustering of the predicted ORFs showed a prevalence of poorly characterized genes, suggesting these lignocellulosic biomasses are potential sources of as yet unknown genes. 1.2%, 0.6% and 3.4% of the total ORFs detected in A. donax, E. camaldulensis and P. nigra, respectively, were putative Carbohydrate-Active Enzymes (CAZymes). Interestingly, the glycoside hydrolases abundance in P. nigra (1.8%) was higher than that detected in the other biomasses investigated in this study. Moreover, a high percentage of (hemi)cellulases with different activities and accessory enzymes (mannanases, polygalacturonases and feruloyl esterases) was detected, confirming that the three analyzed samples were a reservoir of diversified biocatalysts required for an effective lignocellulose saccharification. PMID:28198423

  20. Cellulosic ethanol: progress towards a simulation model of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Petridis, L.; Smith, J. C.

    2008-07-01

    A CHARMM molecular mechanics force field for lignin is derived. Parameterization is based on reproducing quantum mechanical data of model compounds. Partial atomic charges are derived by the examination of methoxybenzene: water interactions. Dihedral parameters are optimized by fitting to critical rotational potentials, and bonded parameters are obtained by optimizing vibrational frequencies and normal modes. The force field is validated by performing a molecular dynamics simulation of a crystal of a lignin fragment molecule and comparing simulation-derived structural features with experimental results. Together with the existing force field for polysaccharides, this work will enable full simulations of lignocellulose.

  1. Direct fungal fermentation of lignocellulosic biomass into itaconic, fumaric, and malic acids: current and future prospects.

    PubMed

    Mondala, Andro H

    2015-04-01

    Various economic and environmental sustainability concerns as well as consumer preference for bio-based products from natural sources have paved the way for the development and expansion of biorefining technologies. These involve the conversion of renewable biomass feedstock to fuels and chemicals using biological systems as alternatives to petroleum-based products. Filamentous fungi possess an expansive portfolio of products including the multifunctional organic acids itaconic, fumaric, and malic acids that have wide-ranging current applications and potentially addressable markets as platform chemicals. However, current bioprocessing technologies for the production of these compounds are mostly based on submerged fermentation, which necessitates physicochemical pretreatment and hydrolysis of lignocellulose biomass to soluble fermentable sugars in liquid media. This review will focus on current research work on fungal production of itaconic, fumaric, and malic acids and perspectives on the potential application of solid-state fungal cultivation techniques for the consolidated hydrolysis and organic acid fermentation of lignocellulosic biomass.

  2. Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach

    PubMed Central

    2014-01-01

    Background Inhibitors are formed that reduce the fermentation performance of fermenting yeast during the pretreatment process of lignocellulosic biomass. An exometabolomics approach was applied to systematically identify inhibitors in lignocellulosic biomass hydrolysates. Results We studied the composition and fermentability of 24 different biomass hydrolysates. To create diversity, the 24 hydrolysates were prepared from six different biomass types, namely sugar cane bagasse, corn stover, wheat straw, barley straw, willow wood chips and oak sawdust, and with four different pretreatment methods, i.e. dilute acid, mild alkaline, alkaline/peracetic acid and concentrated acid. Their composition and that of fermentation samples generated with these hydrolysates were analyzed with two GC-MS methods. Either ethyl acetate extraction or ethyl chloroformate derivatization was used before conducting GC-MS to prevent sugars are overloaded in the chromatograms, which obscure the detection of less abundant compounds. Using multivariate PLS-2CV and nPLS-2CV data analysis models, potential inhibitors were identified through establishing relationship between fermentability and composition of the hydrolysates. These identified compounds were tested for their effects on the growth of the model yeast, Saccharomyces. cerevisiae CEN.PK 113-7D, confirming that the majority of the identified compounds were indeed inhibitors. Conclusion Inhibitory compounds in lignocellulosic biomass hydrolysates were successfully identified using a non-targeted systematic approach: metabolomics. The identified inhibitors include both known ones, such as furfural, HMF and vanillin, and novel inhibitors, namely sorbic acid and phenylacetaldehyde. PMID:24655423

  3. Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach.

    PubMed

    Zha, Ying; Westerhuis, Johan A; Muilwijk, Bas; Overkamp, Karin M; Nijmeijer, Bernadien M; Coulier, Leon; Smilde, Age K; Punt, Peter J

    2014-03-21

    Inhibitors are formed that reduce the fermentation performance of fermenting yeast during the pretreatment process of lignocellulosic biomass. An exometabolomics approach was applied to systematically identify inhibitors in lignocellulosic biomass hydrolysates. We studied the composition and fermentability of 24 different biomass hydrolysates. To create diversity, the 24 hydrolysates were prepared from six different biomass types, namely sugar cane bagasse, corn stover, wheat straw, barley straw, willow wood chips and oak sawdust, and with four different pretreatment methods, i.e. dilute acid, mild alkaline, alkaline/peracetic acid and concentrated acid. Their composition and that of fermentation samples generated with these hydrolysates were analyzed with two GC-MS methods. Either ethyl acetate extraction or ethyl chloroformate derivatization was used before conducting GC-MS to prevent sugars are overloaded in the chromatograms, which obscure the detection of less abundant compounds. Using multivariate PLS-2CV and nPLS-2CV data analysis models, potential inhibitors were identified through establishing relationship between fermentability and composition of the hydrolysates. These identified compounds were tested for their effects on the growth of the model yeast, Saccharomyces. cerevisiae CEN.PK 113-7D, confirming that the majority of the identified compounds were indeed inhibitors. Inhibitory compounds in lignocellulosic biomass hydrolysates were successfully identified using a non-targeted systematic approach: metabolomics. The identified inhibitors include both known ones, such as furfural, HMF and vanillin, and novel inhibitors, namely sorbic acid and phenylacetaldehyde.

  4. Life cycle water footprint of hydrogenation-derived renewable diesel production from lignocellulosic biomass.

    PubMed

    Wong, Alain; Zhang, Hao; Kumar, Amit

    2016-10-01

    The conversion of lignocellulosic biomass to biofuel requires water. This study is focused on the production of hydrogenation-derived renewable diesel (HDRD) from lignocellulosic biomass. Although there has been considerable focus on the assessment of greenhouse gas (GHG) emissions, there is limited work on the assessment of the life cycle water footprint of HDRD production. This paper presents a life cycle water consumption study on lignocellulosic biomass to HDRD via pyrolysis and hydrothermal liquefaction (HTL) processes. The results of this study show that whole tree (i.e., tree chips) biomass has water requirements of 497.79 L/MJ HDRD and 376.16 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Forest residues (i.e., chips from branches and tops generated during logging operations) have water requirements of 338.58 L/MJ HDRD and 255.85 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Agricultural residues (i.e., straw from wheat, oats, and barley), which are more water efficient, have water requirements of 83.7 L/MJ HDRD and 59.1 L/MJ HDRD through fast pyrolysis and the HTL process, respectively. Differences in water use between feedstocks and conversion processes indicate that the choices of biomass feedstock and conversion pathway water efficiency are crucial factors affecting water use efficiency of HDRD production.

  5. Reactors for High Solid Loading Pretreatment of Lignocellulosic Biomass.

    PubMed

    Zhang, Jian; Hou, Weiliang; Bao, Jie

    2016-01-01

    The review summarized the types, the geometry, and the design principle of pretreatment reactors at high solid loading of lignocellulose material. Among the reactors used, the explosion reactors and the helical stirring reactors are to be considered as the practical form for high solids loading pretreatment operation; the comminution reactors and the extruder reactors are difficult to be used as an independent unit, but possible to be used in the combined form with other types of reactors. The principles of the pretreatment reactor design at high solid loading were discussed and several basic principles for the design were proposed. This review provided useful information for choosing the reactor types and designing the geometry of pretreatment operation at the high solids loading.

  6. Supercritical CO2 and ionic liquids for the pretreatment of lignocellulosic biomass in bioethanol production.

    PubMed

    Gu, Tingyue; Held, Michael A; Faik, Ahmed

    2013-01-01

    Owing to high petroleum prices, there has been a major push in recent years to use lignocellulosic biomass as biorefinery feedstocks. Unfortunately, by nature's design, lignocellulosic biomass is notoriously recalcitrant. Cellulose is the most abundant renewable carbon source on the planet and comprises glucan polysaccharides which self-assemble into paracrystalline microfibrils. The extent of cellulose crystallinity largely contributes to biomass recalcitrance. Additionally, cellulose microfibrils are embedded into both hemicellulose and lignin polymeric networks, making cellulose accessibility an additional obstacle. Pretreatment is necessary before enzymatic hydrolysis in order to liberate high yields of glucose and other fermentable sugars from biomass polysaccharides. This work discusses two pretreatment methods, supercritical CO2 and ionic liquids (ILs). Both methods utilize green solvents that do not emit toxic vapours. Mechanisms for destroying or weakening biomass recalcitrance have been explored. Various pretreatment operating parameters such as temperature, pressure, time, dry biomass/solvent ratio, water content, etc. have been investigated for the pretreatment of various biomass types such as corn stover, switchgrass, sugarcane bagasse, soft and hard wood. The two pretreatment methods have their pros and cons. For example, supercritical CO2 explosion pretreatment uses inexpensive CO2, but requires a high pressure. By comparison, while IL pretreatment does not require an elevated pressure, ILs are still too expensive for large-scale uses. Further research and development are needed to make the two green pretreatment methods practical.

  7. Sustainable global energy supply based on lignocellulosic biomass from afforestation of degraded areas.

    PubMed

    Metzger, Jürgen O; Hüttermann, Aloys

    2009-02-01

    An important aspect of present global energy scenarios is the assumption that the amount of biomass that can be grown on the available area is so limited that a scenario based on biomass as the major source of energy should be unrealistic. We have been investigating the question whether a Biomass Scenario may be realistic. We found that the global energy demand projected by the International Energy Agency in the Reference Scenario for the year 2030 could be provided sustainably and economically primarily from lignocellulosic biomass grown on areas which have been degraded by human activities in historical times. Moreover, other renewable energies will contribute to the energy mix. There would be no competition with increasing food demand for existing arable land. Afforestation of degraded areas and investment for energy and fuel usage of the biomass are not more expensive than investment in energy infrastructure necessary up to 2030 assumed in the fossil energy based Reference Scenario, probably much cheaper considering the additional advantages such as stopping the increase of and even slowly reducing the CO(2) content of the atmosphere, soil, and water conservation and desertification control. Most importantly, investment for a Biomass Scenario would be actually sustainable, in contrast to investment in energy-supply infrastructure of the Reference Scenario. Methods of afforestation of degraded areas, cultivation, and energetic usage of lignocellulosic biomass are available but have to be further improved. Afforestation can be started immediately, has an impact in some few years, and may be realized in some decades.

  8. Sustainable global energy supply based on lignocellulosic biomass from afforestation of degraded areas

    NASA Astrophysics Data System (ADS)

    Metzger, Jürgen O.; Hüttermann, Aloys

    2009-02-01

    An important aspect of present global energy scenarios is the assumption that the amount of biomass that can be grown on the available area is so limited that a scenario based on biomass as the major source of energy should be unrealistic. We have been investigating the question whether a Biomass Scenario may be realistic. We found that the global energy demand projected by the International Energy Agency in the Reference Scenario for the year 2030 could be provided sustainably and economically primarily from lignocellulosic biomass grown on areas which have been degraded by human activities in historical times. Moreover, other renewable energies will contribute to the energy mix. There would be no competition with increasing food demand for existing arable land. Afforestation of degraded areas and investment for energy and fuel usage of the biomass are not more expensive than investment in energy infrastructure necessary up to 2030 assumed in the fossil energy based Reference Scenario, probably much cheaper considering the additional advantages such as stopping the increase of and even slowly reducing the CO2 content of the atmosphere, soil, and water conservation and desertification control. Most importantly, investment for a Biomass Scenario would be actually sustainable, in contrast to investment in energy-supply infrastructure of the Reference Scenario. Methods of afforestation of degraded areas, cultivation, and energetic usage of lignocellulosic biomass are available but have to be further improved. Afforestation can be started immediately, has an impact in some few years, and may be realized in some decades.

  9. Echo Particle Image Velocimetry in Pipeflow of Liquefied Lignocellulosic Biomass

    NASA Astrophysics Data System (ADS)

    Demarchi, Nicholas; White, Chris

    2014-11-01

    Echo particle image velocimetry (EPIV) is used to acquire planar fields of velocity in pipeflow of liquefied biomass. The biomass used is acid washed corn stover liquefied by enzymatic hydrolysis. The liquefaction process produces a complex multiphase fluid suspension with a microstructure consisting of insoluble solid particles dispersed within a continuous liquid phase. The solid particles are generally heavier than the liquid phase, non-spherical, and distributed over a wide size range. Batches of liquefied biomass are produced at various mass loadings from 1.5% to 20%, from which samples are withdrawn and used to evaluate the rheology, microstructure, and solid particle settling velocities. Next, EPIV measurements are used to evaluate how the suspension rheology, microstructure, and particle sedimentation affects the flow of liquefied biomass under laminar pipeflow conditions.

  10. Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture.

    PubMed

    Øverland, Margareth; Skrede, Anders

    2017-02-01

    The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation. Studies have shown that yeasts such as Saccharomyces cerevisiae, Candida utilis and Kluyveromyces marxianus have favourable amino acid composition and excellent properties as protein sources in diets for fish, including carnivorous species such as Atlantic salmon and rainbow trout. Suitable downstream processing of the biomass to disrupt cell walls is required to secure high nutrient digestibility. A number of studies have shown various immunological and health benefits from feeding fish low levels of yeast and yeast-derived cell wall fractions. This review summarises current literature on the potential of yeast from lignocellulosic biomass as an alternative protein source for the aquaculture industry. It is concluded that further research and development within yeast production can be important to secure the future sustainability and economic viability of intensive aquaculture. © 2016 Society of Chemical Industry.

  11. Low-Energy Electron Scattering by Sugarcane Lignocellulosic Biomass Molecules

    NASA Astrophysics Data System (ADS)

    Oliveira, Eliane; Sanchez, Sergio; Bettega, Marcio; Lima, Marco; Varella, Marcio

    2012-06-01

    The use of second generation (SG) bioethanol instead of fossil fuels could be a good strategy to reduce greenhouse gas emissions. However, the efficient production of SG bioethanol has being a challenge to researchers around the world. The main barrier one must overcome is the pretreatment, a very important step in SG bioethanol aimed at breaking down the biomass and facilitates the extraction of sugars from the biomass. Plasma-based treatment, which can generate reactive species, could be an interesting possibility since involves low-cost atmospheric-pressure plasma. In order to offer theoretical support to this technique, the interaction of low-energy electrons from the plasma with biomass is investigated. This study was motived by several works developed by Sanche et al., in which they understood that DNA damage arises from dissociative electron attachment, a mechanism in which electrons are resonantly trapped by DNA subunits. We will present elastic cross sections for low-energy electron scattering by sugarcane biomass molecules, obtained with the Schwinger multichannel method. Our calculations indicate the formation of π* shape resonances in the lignin subunits, while a series of broad and overlapping σ* resonances are found in cellulose and hemicellulose subunits. The presence of π* and σ* resonances could give rise to direct and indirect dissociation pathways in biomass. Then, theoretical resonance energies can be useful to guide the plasma-based pretreatment to break down specific linkages of interest in biomass.

  12. Simultaneous Saccharification and Fermentation and Partial Saccharification and Co-Fermentation of Lignocellulosic Biomass for Ethanol Production

    NASA Astrophysics Data System (ADS)

    Doran-Peterson, Joy; Jangid, Amruta; Brandon, Sarah K.; Decrescenzo-Henriksen, Emily; Dien, Bruce; Ingram, Lonnie O.

    Ethanol production by fermentation of lignocellulosic biomass-derived sugars involves a fairly ancient art and an ever-evolving science. Production of ethanol from lignocellulosic biomass is not avant-garde, and wood ethanol plants have been in existence since at least 1915. Most current ethanol production relies on starch- and sugar-based crops as the substrate; however, limitations of these materials and competing value for human and animal feeds is renewing interest in lignocellulose conversion. Herein, we describe methods for both simultaneous saccharification and fermentation (SSF) and a similar but separate process for partial saccharification and cofermentation (PSCF) of lignocellulosic biomass for ethanol production using yeasts or pentose-fermenting engineered bacteria. These methods are applicable for small-scale preliminary evaluations of ethanol production from a variety of biomass sources.

  13. Assessing Cellulase Performance on Pretreated Lignocellulosic Biomass Using Saccharification and Fermentation-Based Protocols

    NASA Astrophysics Data System (ADS)

    Dowe, Nancy

    Cellulase enzyme is a key cost component in the production of fuels and chemicals from lignocellulosic biomass. Cellulolytic ability of the enzyme preparation is often measured by activity assays using model substrates such as filter paper. Using lignocellulosic biomass as the substrate to assess enzyme performance has the potential of being more process relevant. We describe two procedures that use washed pretreated cellulosic material to measure the efficacy of cellulase enzymes. First, a saccharification assay that measures glucose yield as a function of the amount of cellulase used in the process. And second, the simultaneous saccharification and fermentation (SSF) assay measures cellulase performance by the amount of ethanol produced from enzymatic hydrolysis of the cellulosic material. You can use both assays to screen cellulases under a variety of substrate types, loadings, and process conditions.

  14. Supercritical fluids as a green technology for the pretreatment of lignocellulosic biomass.

    PubMed

    Daza Serna, L V; Orrego Alzate, C E; Cardona Alzate, C A

    2016-01-01

    One of the main drawbacks for using lignocellulosic biomass is related to its recalcitrance. The pretreatment of lignocellulosic biomass plays an important role for delignification and crystallinity reduction purposes. In this work rice husk (RH) was submitted to supercritical pretreatment at 80°C and 270 bar with the aim to determine the effect on lignin content, crystallinity as well as enzymatic digestibility. The yields obtained were compared with dilute sulfuric acid pretreatment as base case. Additionally a techno-economic and environmental comparison of the both pretreatment technologies was performed. The results show a lignin content reduction up to 90.6% for the sample with 75% moisture content using a water-ethanol mixture. The results for crystallinity and enzymatic digestibility demonstrated that no reductions were reached. Supercritical pretreatment presents the best economical and environmental performance considering the solvents and carbon dioxide recycling.

  15. High-pressure homogenization pretreatment of four different lignocellulosic biomass for enhancing enzymatic digestibility.

    PubMed

    Jin, Shuguang; Zhang, Guangming; Zhang, Panyue; Fan, Shiyang; Li, Fan

    2015-04-01

    Grass clipping, corn straw, catalpa sawdust and pine sawdust were pretreated with high-pressure homogenization (HPH) to enhance the enzymatic digestibility. With a working pressure of 10 MPa, all the four lignocellulosic biomass were significantly changed, such as decrease in particle size, structure destruction, and crystallinity change. Results showed that lignocellulosic biomass pretreated with HPH yielded more reducing sugar, which was suitable for subsequent biofuel production. After 48-h enzymatic hydrolysis, the maximum reducing sugar yield of 229.42 mg/g was achieved for grass clipping. For corn straw, the enzymatic hydrolysis efficiency increased by 68.37% at most. However, reducing sugar yield of catalpa sawdust and pine sawdust was relatively lower. Low lignin content and crystallinity might make grass clipping the most suitable material for HPH pretreatment, thus leading to high hydrolysis efficiency. HPH pretreatment could increase biofuel output in a mild condition without adding any chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. From lignocellulosic biomass to furans via 5-acetoxymethylfurfural as an alternative to 5-hydroxymethylfurfural.

    PubMed

    Kang, Eun-Sil; Hong, Yeon-Woo; Chae, Da Won; Kim, Bora; Kim, Baekjin; Kim, Yong Jin; Cho, Jin Ku; Kim, Young Gyu

    2015-04-13

    A facile pathway to furan derivatives from lignocellulosic biomass via 5-acetoxymethylfurfural (AMF) was developed. AMF possesses advantageous properties due to its less-hydrophilic acetoxymethyl group relative to the hydroxymethyl group of 5-hydroxymethylfurfural (HMF). The hydrophobicity and chemical stability of AMF allowed practical isolation and purification to afford a highly pure product of up to 99.9 %. AMF was produced in good to excellent yields under mild conditions from 5-chloromethylfurfural (CMF) and alkylammonium acetates, both of which could be obtained directly from lignocellulosic biomass. Heterogeneous reactions with polymer-supported alkylammonium acetates were also established; this showed the feasibility of a continuous process for this pathway. AMF could be transformed into various promising furanic compounds, such as 2,5-furandicarboxylic acid (FDCA), 2,5-furandimethanol (FDM), and 5-hydroxymethyl-2-furanoic acid (HFA), in high yields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Echo Particle Image Velocimetry in Pipeflow of Liquefied Lignocellulosic Biomass

    NASA Astrophysics Data System (ADS)

    Demarchi, Nicholas; White, Christopher

    2016-11-01

    Echo particle image velocimetry (EPIV) is used to acquire planar fields of velocity in pipeflow of liquefied biomass. The biomass used is acid washed corn stover, liquefied through enzymatic hydrolysis. The liquefaction process produces a complex multiphase fluid suspension with a microstructure consisting of insoluble solid particles dispersed within a continuous liquid phase. The solid particles are generally heavier than the liquid phase, non-spherical, and distributed over a wide range of aspect ratios and sizes. Batches of liquefied biomass are produced at incremental mass loadings doubling from 1.5% to 12%, samples are withdrawn to evaluate the rheology, microstructure, and solid particle settling velocities. EPIV is used to experimentally determine the mean particle behaviour under laminar and turbulent pressure driven pipeflow conditions. Work presented in this study can be used to design pipeline infrastructure with respect to suspension transport.

  18. Draft Genome Sequence of a Chitinophaga Strain Isolated from a Lignocellulose Biomass-Degrading Consortium

    PubMed Central

    Kishi, Luciano T.; Lopes, Erica M.; Fernandes, Camila C.; Fernandes, Gabriela C.; Sacco, Lais P.; Carareto Alves, Lucia M.

    2017-01-01

    ABSTRACT Chitinophaga comprises microorganisms capable of degrading plant-derived carbohydrates, serving as a source of new tools for the characterization and degradation of plant biomass. Here, we report the draft genome assembly of a Chitinophaga strain with 8.2 Mbp and 7,173 open reading frames (ORFs), isolated from a bacterial consortium that is able to degrade lignocellulose. PMID:28104646

  19. Utilizing Anaerobic Fungi for Two-stage Sugar Extraction and Biofuel Production from Lignocellulosic Biomass.

    PubMed

    Ranganathan, Abhaya; Smith, Olivia P; Youssef, Noha H; Struchtemeyer, Christopher G; Atiyeh, Hasan K; Elshahed, Mostafa S

    2017-01-01

    Lignocellulosic biomass is a vast and underutilized resource for the production of sugars and biofuels. However, the structural complexity of lignocellulosic biomass and the need for multiple pretreatment and enzymatic steps for sugar release renders this process economically challenging. Here, we report a novel approach for direct, single container, exogenous enzyme-free conversion of lignocellulosic biomass to sugars and biofuels using the anaerobic fungal isolate strain C1A. This approach utilizes simple physiological manipulations for timely inhibition and uncoupling of saccharolytic and fermentative capabilities of strain C1A, leading to the accumulation of sugar monomers (glucose and xylose) in the culture medium. The produced sugars, in addition to fungal hyphal lysate, are subsequently converted by Escherichia coli strain K011 to ethanol. Using this approach, we successfully recovered 17.0% (w/w) of alkali-pretreated corn stover (20.0% of its glucan and xylan content) as sugar monomers in the culture media. More importantly, 14.1% of pretreated corn stover (17.1% of glucan and xylan content) was recovered as ethanol at a final concentration of 28.16 mM after the addition of the ethanologenic strain K011. The high ethanol yield obtained is due to its accumulation as a minor fermentation end product by strain C1A during its initial growth phase, the complete conversion of sugars to ethanol by strain K011, and the possible conversion of unspecified substrates in the hyphal lysate of strain C1A to ethanol by strain K011. This study presents a novel, versatile, and exogenous enzyme-free strategy that utilizes a relatively unexplored group of organisms (anaerobic fungi) for direct biofuel production from lignocellulosic biomass.

  20. Utilizing Anaerobic Fungi for Two-stage Sugar Extraction and Biofuel Production from Lignocellulosic Biomass

    PubMed Central

    Ranganathan, Abhaya; Smith, Olivia P.; Youssef, Noha H.; Struchtemeyer, Christopher G.; Atiyeh, Hasan K.; Elshahed, Mostafa S.

    2017-01-01

    Lignocellulosic biomass is a vast and underutilized resource for the production of sugars and biofuels. However, the structural complexity of lignocellulosic biomass and the need for multiple pretreatment and enzymatic steps for sugar release renders this process economically challenging. Here, we report a novel approach for direct, single container, exogenous enzyme-free conversion of lignocellulosic biomass to sugars and biofuels using the anaerobic fungal isolate strain C1A. This approach utilizes simple physiological manipulations for timely inhibition and uncoupling of saccharolytic and fermentative capabilities of strain C1A, leading to the accumulation of sugar monomers (glucose and xylose) in the culture medium. The produced sugars, in addition to fungal hyphal lysate, are subsequently converted by Escherichia coli strain K011 to ethanol. Using this approach, we successfully recovered 17.0% (w/w) of alkali-pretreated corn stover (20.0% of its glucan and xylan content) as sugar monomers in the culture media. More importantly, 14.1% of pretreated corn stover (17.1% of glucan and xylan content) was recovered as ethanol at a final concentration of 28.16 mM after the addition of the ethanologenic strain K011. The high ethanol yield obtained is due to its accumulation as a minor fermentation end product by strain C1A during its initial growth phase, the complete conversion of sugars to ethanol by strain K011, and the possible conversion of unspecified substrates in the hyphal lysate of strain C1A to ethanol by strain K011. This study presents a novel, versatile, and exogenous enzyme-free strategy that utilizes a relatively unexplored group of organisms (anaerobic fungi) for direct biofuel production from lignocellulosic biomass. PMID:28443088

  1. d-lactic acid production from renewable lignocellulosic biomass via genetically modified Lactobacillus plantarum.

    PubMed

    Zhang, Yixing; Kumar, Amit; Hardwidge, Philip R; Tanaka, Tsutomu; Kondo, Akihiko; Vadlani, Praveen V

    2016-03-01

    d-lactic acid is of great interest because of increasing demand for biobased poly-lactic acid (PLA). Blending poly-l-lactic acid with poly-d-lactic acid greatly improves PLA's mechanical and physical properties. Corn stover and sorghum stalks treated with 1% sodium hydroxide were investigated as possible substrates for d-lactic acid production by both sequential saccharification and fermentation and simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Cellic CTec2) was used for hydrolysis of lignocellulosic biomass and an l-lactate-deficient mutant strain Lactobacillus plantarum NCIMB 8826 ldhL1 and its derivative harboring a xylose assimilation plasmid (ΔldhL1-pCU-PxylAB) were used for fermentation. The SSCF process demonstrated the advantage of avoiding feedback inhibition of released sugars from lignocellulosic biomass, thus significantly improving d-lactic acid yield and productivity. d-lactic acid (27.3 g L(-1) ) and productivity (0.75 g L(-1) h(-1) ) was obtained from corn stover and d-lactic acid (22.0 g L(-1) ) and productivity (0.65 g L(-1) h(-1) ) was obtained from sorghum stalks using ΔldhL1-pCU-PxylAB via the SSCF process. The recombinant strain produced a higher concentration of d-lactic acid than the mutant strain by using the xylose present in lignocellulosic biomass. Our findings demonstrate the potential of using renewable lignocellulosic biomass as an alternative to conventional feedstocks with metabolically engineered lactic acid bacteria to produce d-lactic acid. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:271-278, 2016. © 2016 American Institute of Chemical Engineers.

  2. Pretreatment methods of lignocellulosic biomass for anaerobic digestion.

    PubMed

    Amin, Farrukh Raza; Khalid, Habiba; Zhang, Han; Rahman, Sajid U; Zhang, Ruihong; Liu, Guangqing; Chen, Chang

    2017-12-01

    Agricultural residues, such as lignocellulosic materials (LM), are the most attractive renewable bioenergy sources and are abundantly found in nature. Anaerobic digestion has been extensively studied for the effective utilization of LM for biogas production. Experimental investigation of physiochemical changes that occur during pretreatment is needed for developing mechanistic and effective models that can be employed for the rational design of pretreatment processes. Various-cutting edge pretreatment technologies (physical, chemical and biological) are being tested on the pilot scale. These different pretreatment methods are widely described in this paper, among them, microaerobic pretreatment (MP) has gained attention as a potential pretreatment method for the degradation of LM, which just requires a limited amount of oxygen (or air) supplied directly during the pretreatment step. MP involves microbial communities under mild conditions (temperature and pressure), uses fewer enzymes and less energy for methane production, and is probably the most promising and environmentally friendly technique in the long run. Moreover, it is technically and economically feasible to use microorganisms instead of expensive chemicals, biological enzymes or mechanical equipment. The information provided in this paper, will endow readers with the background knowledge necessary for finding a promising solution to methane production.

  3. Green Processing of Lignocellulosic Biomass and Its Derivatives in Deep Eutectic Solvents.

    PubMed

    Tang, Xing; Zuo, Miao; Li, Zheng; Liu, Huai; Xiong, Caixia; Zeng, Xianhai; Sun, Yong; Hu, Lei; Liu, Shijie; Lei, Tingzhou; Lin, Lu

    2017-07-10

    The scientific community has been seeking cost-competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents (DESs) are currently emerging as a new class of promising solvents that are generally liquid eutectic mixtures formed by self-association (or hydrogen-bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs. DESs are also employed as effective media for the modification of cellulose to afford functionalized cellulosic materials, such as cellulose nanocrystals. More interestingly, biomassderived carbohydrates, such as fructose, can be used as one of the constituents of DESs and then dehydrated to 5-hydroxymethylfurfural in high yield. In this review, a comprehensive summary of recent contribution of DESs to the processing of lignocellulosic biomass and its derivatives is provided. Moreover, further discussion about the challenges of the application of DESs in biomass processing is presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Evolutionary engineering of Saccharomyces cerevisiae for enhanced tolerance to hydrolysates of lignocellulosic biomass.

    PubMed

    Almario, María P; Reyes, Luis H; Kao, Katy C

    2013-10-01

    Lignocellulosic biomass has become an important feedstock to mitigate current ethical and economical concerns related to the bio-based production of fuels and chemicals. During the pre-treatment and hydrolysis of the lignocellulosic biomass, a complex mixture of sugars and inhibitors are formed. The inhibitors interfere with microbial growth and product yields. This study uses an adaptive laboratory evolution method called visualizing evolution in real-time (VERT) to uncover the molecular mechanisms associated with tolerance to hydrolysates of lignocellulosic biomass in Saccharomyces cerevisiae. VERT enables a more rational scheme for isolating adaptive mutants for characterization and molecular analyses. Subsequent growth kinetic analyses of the mutants in individual and combinations of common inhibitors present in hydrolysates (acetic acid, furfural, and hydroxymethylfurfural) showed differential levels of resistance to different inhibitors, with enhanced growth rates up to 57%, 12%, 22%, and 24% in hydrolysates, acetic acid, HMF and furfural, respectively. Interestingly, some of the adaptive mutants exhibited reduced fitness in the presence of individual inhibitors, but showed enhanced fitness in the presence of combinations of inhibitors compared to the parental strains. Transcriptomic analysis revealed different mechanisms for resistance to hydrolysates and a potential cross adaptation between oxidative stress and hydrolysates tolerance in several of the mutants.

  5. Co-hydrogasification of lignocellulosic biomass and swelling coal

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zheng, N.; Wang, J.

    2016-08-01

    The hydrogasification of pine wood (PW) and rice husk (RH) was carried out in a two-stage fixed-bed reactor to investigate the effects of hydrogen pressure and hydrocracking temperature on the yields of gas and tar compositions. The elevation in hydrogen pressure promoted the conversion of two biomasses, leading to the improvement in gaseous hydrocarbons but resulted in a decrease in the yield of BTX (benzene, toluene and xylene). The increased severity of hydrocracking boosted the yield of methane, ethane and BTX mainly at the expense of heavy compounds in tar for PW under 1 MPa. The co-hydrogasification of biomass and DWG swelling coal chiefly showed a synergistic effect on the yields of BTX and PCX (phenol, cresol and xylenol) at 500 °C hydrocracking temperature under 5 MPa.

  6. Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part II: Carbohydrates

    PubMed Central

    Foster, Cliff E.; Martin, Tina M.; Pauly, Markus

    2010-01-01

    The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation2 and other products such as biocomposite materials6. Plant biomass remains one of the greatest untapped reserves on the planet4. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin5 and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation5. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant4. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose7. The protocol for analyzing the

  7. Comprehensive compositional analysis of plant cell walls (lignocellulosic biomass) part II: carbohydrates.

    PubMed

    Foster, Cliff E; Martin, Tina M; Pauly, Markus

    2010-03-12

    The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation(2) and other products such as biocomposite materials(6). Plant biomass remains one of the greatest untapped reserves on the planet(4). It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin(5) and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation(5). Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant(4). Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose(7). The protocol for

  8. A review of thermal-chemical conversion of lignocellulosic biomass in China.

    PubMed

    Ma, Longlong; Wang, Tiejun; Liu, Qiying; Zhang, Xinghua; Ma, Wenchao; Zhang, Qi

    2012-01-01

    Biomass, a renewable, sustainable and carbon dioxide neutral resource, has received widespread attention in the energy market as an alternative to fossil fuels. Thermal-chemical conversion of biomass to produce biofuels is a promising technology with many commercial applications. This paper reviewed the state-of-the-art research and development of thermal-chemical conversion of biomass in China with a special focus on gasification, pyrolysis, and catalytic transformation technologies. The advantages and disadvantages, potential of future applications, and challenges related to these technologies are discussed. Conclusively, these transformation technologies for the second-generation biofuels with using non-edible lignocellulosic biomass as feedstocks show prosperous perspective for commercial applications in near future. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR

    PubMed Central

    Fu, Li; McCallum, Scott A.; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J.; Zhang, Fuming; Linhardt, Robert J.

    2014-01-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of 13C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment. PMID:25404762

  10. Understanding changes in cellulose crystalline structure of lignocellulosic biomass during ionic liquid pretreatment by XRD.

    PubMed

    Zhang, Jiafu; Wang, Yixun; Zhang, Liye; Zhang, Ruihong; Liu, Guangqing; Cheng, Gang

    2014-01-01

    X-ray diffraction (XRD) was used to understand the interactions of cellulose in lignocellulosic biomass with ionic liquids (ILs). The experiment was designed in such a way that the process of swelling and solubilization of crystalline cellulose in plant cell walls was followed by XRD. Three different feedstocks, switchgrass, corn stover and rice husk, were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. At a 5 wt.% biomass loading, increasing pretreatment temperature led to a drop in biomass crystallinity index (CrI), which was due to swelling of crystalline cellulose. After most of the crystalline cellulose was swollen with IL molecules, a low-order structure was found in the pretreated samples. Upon further increasing temperature, cellulose II structure started to form in the pretreated biomass samples as a result of solubilization of cellulose in [C4mim][OAc] and subsequent regeneration.

  11. Deconstruction of lignocellulosic biomass to fuels and chemicals.

    PubMed

    Chundawat, Shishir P S; Beckham, Gregg T; Himmel, Michael E; Dale, Bruce E

    2011-01-01

    Plants represent a vast, renewable resource and are well suited to provide sustainably for humankind's transportation fuel needs. To produce infrastructure-compatible fuels from biomass, two challenges remain: overcoming plant cell wall recalcitrance to extract sugar and phenolic intermediates, and reduction of oxygenated intermediates to fuel molecules. To compete with fossil-based fuels, two primary routes to deconstruct cell walls are under development, namely biochemical and thermochemical conversion. Here, we focus on overcoming recalcitrance with biochemical conversion, which uses low-severity thermochemical pretreatment followed by enzymatic hydrolysis to produce soluble sugars. Many challenges remain, including understanding how pretreatments affect the physicochemical nature of heterogeneous cell walls; determination of how enzymes deconstruct the cell wall effectively with the aim of designing superior catalysts; and resolution of issues associated with the co-optimization of pretreatment, enzymatic hydrolysis, and fermentation. Here, we highlight some of the scientific challenges and open questions with a particular focus on problems across multiple length scales.

  12. Key issues in life cycle assessment of ethanol production from lignocellulosic biomass: Challenges and perspectives.

    PubMed

    Singh, Anoop; Pant, Deepak; Korres, Nicholas E; Nizami, Abdul-Sattar; Prasad, Shiv; Murphy, Jerry D

    2010-07-01

    Progressive depletion of conventional fossil fuels with increasing energy consumption and greenhouse gas (GHG) emissions have led to a move towards renewable and sustainable energy sources. Lignocellulosic biomass is available in massive quantities and provides enormous potential for bioethanol production. However, to ascertain optimal biofuel strategies, it is necessary to take into account environmental impacts from cradle to grave. Life cycle assessment (LCA) techniques allow detailed analysis of material and energy fluxes on regional and global scales. This includes indirect inputs to the production process and associated wastes and emissions, and the downstream fate of products in the future. At the same time if not used properly, LCA can lead to incorrect and inappropriate actions on the part of industry and/or policy makers. This paper aims to list key issues for quantifying the use of resources and releases to the environment associated with the entire life cycle of lignocellulosic bioethanol production.

  13. Influence of lignin addition on the enzymatic digestibility of pretreated lignocellulosic biomasses.

    PubMed

    Wang, Wangxia; Zhu, Yangsu; Du, Jing; Yang, Yiqin; Jin, Yongcan

    2015-04-01

    The presence of lignin in lignocellulosic biomass is correlated with its enzymatic digestibility. Their correlation and mechanism have been investigated widely but have not been elucidated clearly. In this study, hydrophilic sulfonated lignin and hydrophobic kraft lignin were introduced into the enzymatic hydrolysis process to investigate their effects on the enzymatic digestibility of different pretreated lignocellulose. The influence of lignin addition on the enzymatic digestibility varied with both introduced lignin type and the pretreatment methods of substrates. Slight enhancement of enzymatic hydrolysis was observed for all substrates by adding kraft lignin. The addition of sulfonated lignin could effectively improve the enzymatic digestibility of green liquor and acidic bisulfite pretreated materials, but had little effect on sulfite-formaldehyde pretreated samples. The enzymatic digestibility of green liquor pretreated masson pine increased from 42% without lignin addition to 75% with 0.3g/g-substrate sulfonated lignin addition.

  14. Lignocellulosic agriculture wastes as biomass feedstocks for second-generation bioethanol production: concepts and recent developments.

    PubMed

    Saini, Jitendra Kumar; Saini, Reetu; Tewari, Lakshmi

    2015-08-01

    Production of liquid biofuels, such as bioethanol, has been advocated as a sustainable option to tackle the problems associated with rising crude oil prices, global warming and diminishing petroleum reserves. Second-generation bioethanol is produced from lignocellulosic feedstock by its saccharification, followed by microbial fermentation and product recovery. Agricultural residues generated as wastes during or after processing of agricultural crops are one of such renewable and lignocellulose-rich biomass resources available in huge amounts for bioethanol production. These agricultural residues are converted to bioethanol in several steps which are described here. This review enlightens various steps involved in production of the second-generation bioethanol. Mechanisms and recent advances in pretreatment, cellulases production and second-generation ethanol production processes are described here.

  15. Conversion of lignocellulosic biomass into its molecular components by sequential combination of organic acid and base

    NASA Astrophysics Data System (ADS)

    Noda, Yu

    The primary objective of this research is to explore a new concept of converting lignocellulosic biomass into liquid organic products via hydrolysis by sequentially combining acid and base treatments. The concept was examined by studying two-step hydrolytic reactions of biomass (spruce) using oxialic acid (OA) and tetramethylammonium hydroxide (TMAH) at moderate reaction temperatures below 200 °C. Different selectivity of C-O bond cleavage of hemicellulose, cellulose, and lignin between the reactions with OA and TMAH was demonstrated, and the sequential combination of OA and TMAH treatments exhibited an enhancing effect on conversion of biomass, which proves the promise of the proposed concept. A similar enhancing effect of combination was further confirmed in the reactions with mineral acid and base. Interestingly, characterization of solid residue from reactions of biomass and further investigation of the reactions of commercial cellulose revealed that the A-B sequence (the first reaction with OA and the second with TMAH) enhanced the conversion of cellulose at the second step with TMAH. It was suggested from the NMR and XRD study of solid residues that this enhancement was caused by the reduction of crystallinity of cellulose by the first reaction with OA. This effect was shown to be an interesting feature of A-B treatment sequence for converting lignocellulosic biomass. To improve the yield of monomeric sugars, the effect of adding organic solvents to the system was also studied. No improvement on sugar yield was observed under the explored conditions. However, it was shown that some furans and phenols can be directly formed from the reactions of biomass in the binary solvent system, which may be beneficial for producing more value-added chemicals from biomass.

  16. Enhanced hydrolysis of lignocellulosic biomass: Bi-functional enzyme complexes expressed in Pichia pastoris improve bioethanol production from Miscanthus sinensis.

    PubMed

    Shin, Sang Kyu; Hyeon, Jeong Eun; Kim, Young In; Kang, Dea Hee; Kim, Seung Wook; Park, Chulhwan; Han, Sung Ok

    2015-12-01

    Lignocellulosic biomass is the most abundant utilizable natural resource. In the process of bioethanol production from lignocellulosic biomass, an efficient hydrolysis of cellulose and hemicellulose to release hexose and pentose is essential. We have developed a strain of Pichia pastoris that can produce ethanol via pentose and hexose using an assembly of enzyme complexes. The use of enzyme complexes is one of the strategies for effective lignocellulosic biomass hydrolysis. Xylanase XynB from Clostridium cellulovorans and a chimeric endoglucanase cCelE from Clostridium thermocellum were selected as enzyme subunits, and were bound to a recombinant scaffolding protein mini-CbpA from C. cellulovorans to assemble the enzyme complexes. These complexes efficiently degraded xylan and carboxymethylcellulose (CMC), producing approximately 1.18 and 1.07 g/L ethanol from each substrate, respectively, which is 2.3-fold and 2.7-fold higher than that of the free-enzyme expressing strain. Miscanthus sinensis was investigated as the lignocellulosic biomass for producing bioethanol, and 1.08 g/L ethanol was produced using our recombinant P. pastoris strain, which is approximately 1.9-fold higher than that of the wild-type strain. In future research, construction of enzyme complexes containing various hydrolysis enzymes could be used to develop biocatalysts that can completely degrade lignocellulosic biomass into valuable products such as biofuels.

  17. Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight secondary ion mass spectrometry

    DOE PAGES

    Tolbert, Allison K.; Ragauskas, Arthur J.

    2016-12-12

    Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires some type of chemical pretreatment and/or biological treatment. While bulk chemical analysis is the traditional method of determining the impact a treatment has on biomass, the chemistry on the surface of the sample can differ from the bulk chemistry. Specifically, enzymes and microorganisms bind to the surface of the biomass and their efficiency could be greatly impacted by the chemistry of the surface. Therefore, it is important to study and understand the chemistry of the biomassmore » at the surface. Time-of- flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool that can spectrally and spatially analyze the surface chemistry of a sample. This review discusses the advances in understanding lignocellulosic biomass surface chemistry using the ToF-SIMS by addressing the instrument parameters, biomass sample preparation, and characteristic lignocellulosic ion fragmentation peaks along with their typical location in the plant cell wall. Furthermore, the use of the ToF-SIMS in detecting chemical changes due to chemical pretreatments, microbial treatments, and physical or genetic modifications is discussed along with possible future applications of the instrument in lignocellulosic biomass studies.« less

  18. Liquefaction of lignocellulosic biomass: solvent, process parameter, and recycle oil screening.

    PubMed

    van Rossum, Guus; Zhao, Wei; Castellvi Barnes, Maria; Lange, Jean-Paul; Kersten, Sascha R A

    2014-01-01

    The liquefaction of lignocellulosic biomass is studied for the production of liquid (transportation) fuels. The process concept uses a product recycle as a liquefaction medium and produces a bio-oil that can be co-processed in a conventional oil refinery. This all is done at medium temperature (≈ 300 °C) and pressure (≈ 60 bar). Solvent-screening experiments showed that oxygenated solvents are preferred as they allow high oil (up to 93% on carbon basis) and low solid yields (≈ 1-2% on carbon basis) and thereby outperform the liquefaction of biomass in compressed water and biomass pyrolysis. The following solvent ranking was obtained: guaiacol>hexanoic acid ≫ n-undecane. The use of wet biomass results in higher oil yields than dry biomass. However, it also results in a higher operating pressure, which would make the process more expensive. Refill experiments were also performed to evaluate the possibility to recycle the oil as the liquefaction medium. The recycled oil appeared to be very effective to liquefy the biomass and even surpassed the start-up solvent guaiacol, but became increasingly heavy and more viscous after each refill and eventually showed a molecular weight distribution that resembles that of refinery vacuum residue. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Comprehensive compositional analysis of plant cell walls (Lignocellulosic biomass) part I: lignin.

    PubMed

    Foster, Cliff E; Martin, Tina M; Pauly, Markus

    2010-03-11

    The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation(1) and other products such as biocomposite materials(7). Plant biomass remains one of the greatest untapped reserves on the planet(4). It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses (matrix polysaccharides, and the polyphenol lignin(6) and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls provide tensile strength to cells and the entire plants, ward off pathogens, and allow water to be transported throughout the plant; in the case of trees up to more the 100 m above ground level. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant(4). Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerization by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis. In this first part we focus on the analysis of the polyphenol lignin (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its lignin content by acetylbromide solubilization(3), and its lignin composition in terms of its syringyl, guaiacyl- and p-hydroxyphenyl units(5

  20. Utilization of hydrolysate from lignocellulosic biomass pretreatment to generate electricity by enzymatic fuel cell system.

    PubMed

    Kim, Sung Bong; Kim, Dong Sup; Yang, Ji Hyun; Lee, Junyoung; Kim, Seung Wook

    2016-04-01

    The waste hydrolysate after dilute acid pretreatment (DAP) of lignocellulosic biomass was utilized to generate electricity using an enzymatic fuel cell (EFC) system. During DAP, the components of biomass containing hemicellulose and other compounds are hydrolyzed, and glucose is solubilized into the dilute acid solution, called as the hydrolysate liquid. Glucose oxidase (GOD) and laccase (Lac) were assembled on the electrode of the anode and cathode, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were measured, and the maximum power density was found to be 1.254×10(3) μW/cm(2). The results indicate that the hydrolysate from DAP is a reliable electrolyte containing the fuel of EFC. Moreover, the impurities in the hydrolysate such as phenols and furans slightly affected the charge transfer on the surface of the electrode, but did not affect the power generation of the EFC system in principal.

  1. Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Tai, Chao; Voltan, Diego S; Keshwani, Deepak R; Meyer, George E; Kuhar, Pankaj S

    2016-06-01

    A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.

  2. Ectoine production from lignocellulosic biomass-derived sugars by engineered Halomonas elongata.

    PubMed

    Tanimura, Kosuke; Nakayama, Hideki; Tanaka, Tsutomu; Kondo, Akihiko

    2013-08-01

    In this study, the water-retaining cyclic amino acid ectoine was produced from a variety of sugars, including glucose, xylose, cellobiose, and glucose/xylose mixture using engineered Halomonas elongata. When grown on xylose as the sole carbon source, H. elongata produced 333 mmol/kg fresh cell weight (FW) of ectoine, which was 1.4-fold higher than that produced from glucose. To improve ectoine production, an ectD deficient H. elongata mutant was constructed. The engineered H. elongata produced 377 mmol/kg FW of ectoine from a glucose/xylose mixture. Ectoine was also produced from rice straw hydrolysate. These results show that H. elongata can produce ectoine from a variety of sugars derived from lignocellulosic biomass and thus has tremendous potential as a host for producing useful compounds from biomass resources.

  3. A review of catalytic microwave pyrolysis of lignocellulosic biomass for value-added fuel and chemicals.

    PubMed

    Morgan, Hervan Marion; Bu, Quan; Liang, Jianghui; Liu, Yujing; Mao, Hanping; Shi, Aiping; Lei, Hanwu; Ruan, Roger

    2017-04-01

    Lignocellulosic biomass is an abundant renewable resource and can be efficiently converted into bio-energy by a bio-refinery. From the various techniques available for biomass thermo-chemical conversion; microwave assisted pyrolysis (MAP) seems to be the very promising. The principles of microwave technology were reviewed and the parameters for the efficient production of bio-oil using microwave technology were summarized. Microwave technology by itself cannot efficiently produce high quality bio-oil products, catalysts are used to improve the reaction conditions and selectivity for valued products during MAP. The catalysts used to optimize MAP are revised in the development of this article. The origins for bio-oils that are phenol rich or hydrocarbon rich are reviewed and their experimental results were summarized. The kinetics of MAP is discussed briefly in the development of the article. Future prospects and scientific development of MAP are also considered in the development of this article.

  4. A Comparative study of microwave-induced pyrolysis of lignocellulosic and algal biomass.

    PubMed

    Wang, Nan; Tahmasebi, Arash; Yu, Jianglong; Xu, Jing; Huang, Feng; Mamaeva, Alisa

    2015-08-01

    Microwave (MW) pyrolysis of algal and lignocellulosic biomass samples were studied using a modified domestic oven. The pyrolysis temperature was recorded continuously by inserting a thermocouple into the samples. Temperatures as high as 1170 and 1015°C were achieved for peanut shell and Chlorella vulgaris. The activation energy for MW pyrolysis was calculated by Coats-Redfern method and the values were 221.96 and 214.27kJ/mol for peanut shell and C. vulgaris, respectively. Bio-oil yields reached to 27.7wt.% and 11.0wt.% during pyrolysis of C. vulgaris and peanut shell, respectively. The bio-oil samples from pyrolysis were analyzed by a gas chromatography-mass spectrometry (GC-MS). Bio-oil from lignocellulosic biomass pyrolysis contained more phenolic compounds while that from microalgae pyrolysis contained more nitrogen-containing species. Fourier transform infrared spectroscopy (FTIR) analysis results showed that concentration of OH, CH, CO, OCH3, and CO functional groups in char samples decreased significantly after pyrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Energy performance of an integrated bio-and-thermal hybrid system for lignocellulosic biomass waste treatment.

    PubMed

    Kan, Xiang; Yao, Zhiyi; Zhang, Jingxin; Tong, Yen Wah; Yang, Wenming; Dai, Yanjun; Wang, Chi-Hwa

    2017-03-01

    Lignocellulosic biomass waste, a heterogeneous complex of biodegradables and non-biodegradables, accounts for large proportion of municipal solid waste. Due to limitation of single-stage treatment, a two-stage hybrid AD-gasification system was proposed in this work, in which AD acted as pre-treatment to convert biodegradables into biogas followed by gasification converting solid residue into syngas. Energy performance of single and two-stage systems treating 3 typical lignocellulosic wastes was studied using both experimental and numerical methods. In comparison with conventional single-stage gasification treatment, this hybrid system could significantly improve the quality of produced gas for all selected biomass wastes and show its potential in enhancing total gas energy production by a maximum value of 27% for brewer's spent grain treatment at an organic loading rate (OLR) of 3gVS/L/day. The maximum overall efficiency of the hybrid system for horticultural waste treatment was 75.2% at OLR of 11.3gVS/L/day, 5.5% higher than conventional single-stage system.

  6. Biochemical Conversion Processes of Lignocellulosic Biomass to Fuels and Chemicals - A Review.

    PubMed

    Brethauer, Simone; Studer, Michael H

    2015-01-01

    Lignocellulosic biomass - such as wood, agricultural residues or dedicated energy crops - is a promising renewable feedstock for production of fuels and chemicals that is available at large scale at low cost without direct competition for food usage. Its biochemical conversion in a sugar platform biorefinery includes three main unit operations that are illustrated in this review: the physico-chemical pretreatment of the biomass, the enzymatic hydrolysis of the carbohydrates to a fermentable sugar stream by cellulases and finally the fermentation of the sugars by suitable microorganisms to the target molecules. Special emphasis in this review is put on the technology, commercial status and future prospects of the production of second-generation fuel ethanol, as this process has received most research and development efforts so far. Despite significant advances, high enzyme costs are still a hurdle for large scale competitive lignocellulosic ethanol production. This could be overcome by a strategy termed 'consolidated bioprocessing' (CBP), where enzyme production, enzymatic hydrolysis and fermentation is integrated in one step - either by utilizing one genetically engineered superior microorganism or by creating an artificial co-culture. Insight is provided on both CBP strategies for the production of ethanol as well as of advanced fuels and commodity chemicals.

  7. Analysis of casein biopolymers adsorption to lignocellulosic biomass as a potential cellulase stabilizer.

    PubMed

    Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William

    2012-01-01

    Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), capillary electrophoresis (CE), and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorption of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively.

  8. Analysis of Casein Biopolymers Adsorption to Lignocellulosic Biomass as a Potential Cellulase Stabilizer

    PubMed Central

    Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William

    2012-01-01

    Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), capillary electrophoresis (CE), and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorption of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively. PMID:23118515

  9. Analysis of Casein Biopolymers Adsorption to Lignocellulosic Biomass as a Potential Cellulase Stabilizer

    DOE PAGES

    Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William

    2012-01-01

    Although lignocellulosic materials have a good potential to substitute current feedstocks used for ethanol production, conversion of these materials to fermentable sugars is still not economical through enzymatic hydrolysis. High cost of cellulase has prompted research to explore techniques that can prevent from enzyme deactivation. Colloidal proteins of casein can form monolayers on hydrophobic surfaces that alleviate the de-activation of protein of interest. Scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), capillary electrophoresis (CE), and Kjeldahl and BSA protein assays were used to investigate the unknown mechanism of action of induced cellulase activity during hydrolysis of casein-treated biomass. Adsorptionmore » of casein to biomass was observed with all of the analytical techniques used and varied depending on the pretreatment techniques of biomass. FT-IR analysis of amides I and II suggested that the substructure of protein from casein or skim milk were deformed at the time of contact with biomass. With no additive, the majority of one of the cellulase mono-component, 97.1 ± 1.1, was adsorbed to CS within 24 h, this adsorption was irreversible and increased by 2% after 72 h. However, biomass treatment with skim-milk and casein reduced the adsorption to 32.9% ± 6.0 and 82.8% ± 6.0, respectively.« less

  10. Saccharification of recalcitrant biomass and integration options for lignocellulosic sugars from Catchlight Energy’s sugar process (CLE Sugar)

    PubMed Central

    2013-01-01

    Background Woody biomass is one of the most abundant biomass feedstocks, besides agriculture residuals in the United States. The sustainable harvest residuals and thinnings alone are estimated at about 75 million tons/year. These forest residuals and thinnings could produce the equivalent of 5 billion gallons of lignocellulosic ethanol annually. Softwood biomass is the most recalcitrant biomass in pretreatment before an enzymatic hydrolysis. To utilize the most recalcitrant lignocellulosic materials, an efficient, industrially scalable and cost effective pretreatment method is needed. Results Obtaining a high yield of sugar from recalcitrant biomass generally requires a high severity of pretreatment with aggressive chemistry, followed by extensive conditioning, and large doses of enzymes. Catchlight Energy’s Sugar process, CLE Sugar, uses a low intensity, high throughput variation of bisulfite pulping to pretreat recalcitrant biomass, such as softwood forest residuals. By leveraging well-proven bisulfite technology and the rapid progress of enzyme suppliers, CLE Sugar can achieve a high yield of total biomass carbohydrate conversion to monomeric lignocellulosic sugars. For example, 85.8% of biomass carbohydrates are saccharified for un-debarked Loblolly pine chips (softwood), and 94.0% for debarked maple chips (hardwood). Furan compound formation was 1.29% of biomass feedstock for Loblolly pine and 1.10% for maple. At 17% solids hydrolysis of pretreated softwood, an enzyme dose of 0.075 g Sigma enzyme mixture/g dry pretreated (unwashed) biomass was needed to achieve 8.1% total sugar titer in the hydrolysate and an overall prehydrolysate liquor plus enzymatic hydrolysis conversion yield of 76.6%. At a much lower enzyme dosage of 0.044 g CTec2 enzyme product/g dry (unwashed) pretreated softwood, hydrolysis at 17% solids achieved 9.2% total sugar titer in the hydrolysate with an overall sugar yield of 85.0% in the combined prehydrolysate liquor and enzymatic

  11. Alkaline/peracetic acid as a pretreatment of lignocellulosic biomass for ethanol fuel production

    NASA Astrophysics Data System (ADS)

    Teixeira, Lincoln Cambraia

    Peracetic acid is a lignin oxidation pretreatment with low energy input by which biomass can be treated in a silo type system for improving enzymatic digestibility of lignocellulosic materials for ethanol production. Experimentally, ground hybrid poplar wood and sugar cane bagasse are placed in plastic bags and a peracetic acid solution is added to the biomass in different concentrations based on oven-dry biomass. The ratio of solution to biomass is 6:1; after initial mixing of the resulting paste, a seven-day storage period at about 20°C is used in this study. As a complementary method, a series of pre-pretreatments using stoichiometric amounts of sodium hydroxide and ammonium hydroxide based on 4-methyl-glucuronic acid and acetyl content in the biomass is been performed before addition of peracetic acid. The alkaline solutions are added to the biomass in a ratio of 14:1 solution to biomass; the slurry is mixed for 24 hours at ambient temperature. The above procedures give high xylan content substrates. Consequently, xylanase/beta-glucosidase combinations are more effective than cellulase preparations in hydrolyzing these materials. The pretreatment effectiveness is evaluated using standard enzymatic hydrolysis and simultaneous saccharification and cofermentation (SSCF) procedures. Hybrid poplar wood pretreated with 15 and 21% peracetic acid based on oven-dry weight of wood gives glucan conversion yields of 76.5 and 98.3%, respectively. Sugar cane bagasse pretreated with the same loadings gives corresponding yields of 85.9 and 93.1%. Raw wood and raw bagasse give corresponding yields of 6.8 and 28.8%, respectively. The combined 6% NaOH/15% peracetic acid pretreatments increase the glucan conversion yields from 76.5 to 100.0% for hybrid poplar wood and from 85.9 to 97.6% for sugar cane bagasse. Respective ethanol yields of 92.8 and 91.9% are obtained from 6% NaOH/15% peracetic acid pretreated materials using recombinant Zymomonas mobilis CP4/pZB5. Peracetic acid

  12. Acetic acid and lithium chloride effects on hydrothermal carbonization of lignocellulosic biomass.

    PubMed

    Lynam, Joan G; Coronella, Charles J; Yan, Wei; Reza, Mohammad T; Vasquez, Victor R

    2011-05-01

    As a renewable non-food resource, lignocellulosic biomass has great potential as an energy source or feedstock for further conversion. However, challenges exist with supply logistics of this geographically scattered and perishable resource. Hydrothermal carbonization treats any kind of biomass in 200 to 260°C compressed water under an inert atmosphere to produce a hydrophobic solid of reduced mass and increased fuel value. A maximum in higher heating value (HHV) was found when 0.4 g of acetic acid was added per g of biomass. If 1g of LiCl and 0.4 g of acetic acid were added per g of biomass to the initial reaction solution, a 30% increase in HHV was found compared to the pretreatment with no additives, along with greater mass reduction. LiCl addition also reduces reaction pressure. Addition of acetic acid and/or LiCl to hydrothermal carbonization each contribute to increased HHV and reduced mass yield of the solid product.

  13. C4 plants as biofuel feedstocks: optimising biomass production and feedstock quality from a lignocellulosic perspective.

    PubMed

    Byrt, Caitlin S; Grof, Christopher P L; Furbank, Robert T

    2011-02-01

    The main feedstocks for bioethanol are sugarcane (Saccharum officinarum) and maize (Zea mays), both of which are C(4) grasses, highly efficient at converting solar energy into chemical energy, and both are food crops. As the systems for lignocellulosic bioethanol production become more efficient and cost effective, plant biomass from any source may be used as a feedstock for bioethanol production. Thus, a move away from using food plants to make fuel is possible, and sources of biomass such as wood from forestry and plant waste from cropping may be used. However, the bioethanol industry will need a continuous and reliable supply of biomass that can be produced at a low cost and with minimal use of water, fertilizer and arable land. As many C(4) plants have high light, water and nitrogen use efficiency, as compared with C(3) species, they are ideal as feedstock crops. We consider the productivity and resource use of a number of candidate plant species, and discuss biomass 'quality', that is, the composition of the plant cell wall. © 2011 Institute of Botany, Chinese Academy of Sciences.

  14. Nanostructured Photocatalysts and Their Applications in the Photocatalytic Transformation of Lignocellulosic Biomass: An Overview

    PubMed Central

    Colmenares, Juan Carlos; Luque, Rafael; Campelo, Juan Manuel; Colmenares, Fernando; Karpiński, Zbigniew; Romero, Antonio Angel

    2009-01-01

    Heterogeneous photocatalysis offer many possibilities for finding appropiate environmentally friendly solutions for many of the the problems affecting our society (i.e., energy issues). Researchers are still looking for novel routes to prepare solid photocatalysts able to transform solar into chemical energy more efficiently. In many developing countries, biomass is a major energy source, but currently such countries lack of the technology to sustainably obtain chemicals and/or fuels from it. The Roadmap for Biomass Technologies, authored by 26 leading experts from academia, industry, and government agencies, has predicted a gradual shift back to a carbohydrate-based economy. Biomass and biofuels appear to hold the key to satisfy the basic needs of our societies for the sustainable production of liquid fuels and high value-added chemicals without compromising the scenario of future generations. In this review, we aim to discuss various design routes for nanostructured photocatalytic solid materials in view of their applications in the selective transformation of lignocellulosic biomass to high value-added chemicals.

  15. Exometabolomics Approaches in Studying the Application of Lignocellulosic Biomass as Fermentation Feedstock

    PubMed Central

    Zha, Ying; Punt, Peter J.

    2013-01-01

    Lignocellulosic biomass is the future feedstock for the production of biofuel and bio-based chemicals. The pretreatment-hydrolysis product of biomass, so-called hydrolysate, contains not only fermentable sugars, but also compounds that inhibit its fermentability by microbes. To reduce the toxicity of hydrolysates as fermentation media, knowledge of the identity of inhibitors and their dynamics in hydrolysates need to be obtained. In the past decade, various studies have applied targeted metabolomics approaches to examine the composition of biomass hydrolysates. In these studies, analytical methods like HPLC, RP-HPLC, CE, GC-MS and LC-MS/MS were used to detect and quantify small carboxylic acids, furans and phenols. Through applying targeted metabolomics approaches, inhibitors were identified in hydrolysates and their dynamics in fermentation processes were monitored. However, to reveal the overall composition of different hydrolysates and to investigate its influence on hydrolysate fermentation performance, a non-targeted metabolomics study needs to be conducted. In this review, a non-targeted and generic metabolomics approach is introduced to explore inhibitor identification in biomass hydrolysates, and other similar metabolomics questions. PMID:24957893

  16. Optimization of hydrothermal pretreatment of lignocellulosic biomass in the bioethanol production process.

    PubMed

    Nitsos, Christos K; Matis, Konstantinos A; Triantafyllidis, Kostas S

    2013-01-01

    The natural resistance to enzymatic deconstruction exhibited by lignocellulosic materials has designated pretreatment as a key step in the biological conversion of biomass to ethanol. Hydrothermal pretreatment in pure water represents a challenging approach because it is a method with low operational costs and does not involve the use of organic solvents, difficult to handle chemicals, and "external" liquid or solid catalysts. In the present work, a systematic study has been performed to optimize the hydrothermal treatment of lignocellulosic biomass (beech wood) with the aim of maximizing the enzymatic digestibility of cellulose in the treated solids and obtaining a liquid side product that could also be utilized for the production of ethanol or valuable chemicals. Hydrothermal treatment experiments were conducted in a batch-mode, high-pressure reactor under autogeneous pressure at varying temperature (130-220 °C) and time (15-180 min) regimes, and at a liquid-to-solid ratio (LSR) of 15. The intensification of the process was expressed by the severity factor, log R(o). The major changes induced in the solid biomass were the dissolution/removal of hemicellulose to the process liquid and the partial removal and relocation of lignin on the external surface of biomass particles in the form of recondensed droplets. The above structural changes led to a 2.5-fold increase in surface area and total pore volume of the pretreated biomass solids. The enzymatic hydrolysis of cellulose to glucose increased from less than 7 wt% for the parent biomass to as high as 70 wt% for the treated solids. Maximum xylan recovery (60 wt%) in the hydrothermal process liquid was observed at about 80 wt% hemicellulose removal; this was accomplished by moderate treatment severities (log R(o)=3.8-4.1). At higher severities (log R(o)=4.7), xylose degradation products, mainly furfural and formic acid, were the predominant chemicals formed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGa

  17. Improving the bioconversion yield of carbohydrates and ethanol from lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Ewanick, Shannon M.

    Improving the efficiency of lignocellulosic ethanol production is of the utmost importance if cellulosic bioethanol is to be competitive with fossil fuels and first generation bioethanol from starch and sucrose. Improvements in individual processes (pretreatment, saccharification, fermentation) have been ongoing, but few researchers have considered the effect that the incoming raw biomass can have on the process. It is important to understand how biomass can be altered to provide the maximum yield of hydrolysable and fermentable sugars from whatever is available. Since the moisture content is highly variable and easily altered, the effect of drying and rewetting on bioconversion was studied on switchgrass, sugarcane bagasse and hybrid poplar. For switchgrass and sugarcane bagasse, the ethanol yield after simultaneous saccharification and fermentation was improved 18-24% by increasing the moisture content by soaking prior to pretreatment. It was also found that soaking had no effect when the samples were not catalyzed with SO2 confirming that the effect of moisture content is directly related to SO2 uptake and diffusion into the biomass. In hybrid poplar, the results were similar to herbaceous biomass for chips with less than 2% absorbed SO2. However, when the SO2 uptake was increased to 3% even the air dried chips exhibited high digestibility, indicating that increased SO2 uptake can overcome the poor diffusion in dried biomass. Alongside controlling the biomass moisture content, improving knowledge and control of the processes can also increase efficiency and product yields. By monitoring reactions continuously with accurate, robust, on-line sensors, operators can detect when reactions deviate from the norm, and when they are complete. Avoiding process upsets and contamination could be the difference between an economically viable biorefinery and one that struggles to compete. Real time, continuous Raman spectroscopy was used to continuously monitor both a

  18. Efficiencies of acid catalysts in the hydrolysis of lignocellulosic biomass over a range of combined severity factors

    Treesearch

    Jae-Won Lee; Thomas W. Jeffries

    2011-01-01

    Dicarboxylic organic acids have properties that differ from those of sulfuric acid during hydrolysis of lignocellulose. To investigate the effects of different acid catalysts on the hydrolysis and degradation of biomass compounds over a range of thermochemical pretreatments, maleic, oxalic and sulfuric acids were each used at the same combined severity factor (CSF)...

  19. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass

    USDA-ARS?s Scientific Manuscript database

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors [such as furfural and 5-hydroxymethylfurfural (HMF)] to less toxic corresponding alcohols. However, the...

  20. Physicochemical characterization of lignin recovered from microwave-assisted delignified lignocellulosic biomass for use in biobased materials

    Treesearch

    Jiulong Xie; Chung-Yun Hse; Todd F. Shupe; Tingxing Hu

    2015-01-01

    Lignocellulosic biomass (Moso Bamboo, Chinese tallow tree wood, switchgrass, and pine wood) was subjected to a novel delignification process using microwave energy in a binary glycerol/methanol solvent. The physicochemical properties of the recovered lignin were analyzed prior to its application in the fabrication of polylactic acid (PLA)–lignin composites. The results...

  1. High-Solids Enzymatic Saccharification Screening Method for Lignocellulosic Biomass (Poster)

    SciTech Connect

    Roche, C. M.; Stickel, J. J.

    2009-05-01

    The ability to screen new biomass pretreatments and advanced enzyme systems at process-relevant conditions is key to developing economically viable lignocellulosic ethanol. While much research is being invested in developing pretreatment technologies and enzyme systems that will more efficiently convert cellulosic biomass to sugars, the current standard reactor vessel, a shake flask, that is used for screening enzymatic saccharification of cellulosic biomass is inadequate at high-solids conditions. Shake flasks do not provide adequate mixing at high solids conditions. In this work, a roller bottle reactor was identified as a small-scale high-solids saccharification reaction vessel, and a method was developed for use in screening both pretreated biomass and enzyme systems at process-relevant conditions. This new method addresses mixing issues observed in high-solids saccharifications. In addition, yield calculations from sugar concentrations on a mass basis were used to account for the two-phase nature of the saccharification slurry, which eliminates discontinuities in comparing high-solids to low-solids saccharifications that occur when using concentrations on a volume basis. The roller bottle reactors out-performed the shake flasks by 5% for an initial insoluble solids loading of 15% and 140% for an initial soluble solids loading of 30%. The reactor system and method was compared at bench and floor scales and determined to be scalable for initial insoluble solids loading in the range of 15% to 30%. Pretreatment and enzyme screening results indicate that mid severity pretreated biomass is more digestible than the low and high severity biomass and GC220 is a superior enzyme to Spezyme CP.

  2. Elucidating the Role of Ferrous Ion Cocatalyst in Enhancing Dilute Acid Pretreatment of Lignocellulosic Biomass

    SciTech Connect

    Wei, H.; Donohoe, B. S.; Vinzant, T. B.; Ciesielski, P. N.; Wang, W.; Gedvilas, L. M.; Zeng, Y.; Johnson, D. K.; Ding, S. Y.; Himmel, M. E.; Tucker, M. P.

    2011-01-01

    Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe{sup 2+} ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe{sup 2+} ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe{sup 2+} ion pretreatment, in which delamination and fibrillation of the cell wall were observed. By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.

  3. Modeling Sucrose Hydrolysis in Dilute Sulfuric Acid Solutions at Pretreatment Conditions for Lignocellulosic Biomass

    SciTech Connect

    Bower, S.; Wickramasinghe, R.; Nagle, N. J.; Schell, D. J.

    2008-01-01

    Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25 g/l sucrose with 0.1-2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160-200 C for 3-12 min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products.

  4. Production of Biofuel from Waste Lignocellulosic Biomass Materials Based on Energy Saving Viewpoint

    NASA Astrophysics Data System (ADS)

    Takano, Maki; Hoshino, Kazuhiro

    To develop biofuel production from waste lignocellulosic biomass materials the rice straw was selected one of renewable material and the degradation condition about pretreatment and enzymatic hydrolysis to obtain effectively fermentable sugars was investigated. Rice straw was pretreated by five kinds of methods and then the components ratio of rice straw was examined. First, the steam explosion was selected based on the degradability and the requirement energy. In addition, the best suitable combination of two cellulases to effective and economical hydrolyze was determined from the degradability of these pretreated rice straws. In the simultaneous saccharification and fermentation of the steam explosion rice straw by combining cellulase cocktail and a novel fermenting fungus, 13.2 g/L ethanol was able to product for 96 h.

  5. Optimal control strategy for fed-batch enzymatic hydrolysis of lignocellulosic biomass based on epidemic modeling.

    PubMed

    Tai, Chao; Keshwani, Deepak R; Voltan, Diego S; Kuhar, Pankaj S; Engel, Aaron J

    2015-07-01

    A mathematical optimal control strategy for feeding operation was developed for fed-batch enzymatic hydrolysis of dilute acid pretreated lignocellulosic biomass based on a modified epidemic model. Cellulose conversion was maximized and glucose concentration achieved highest possible value over a fixed hydrolysis time. Boundaries of feeding rate and lignin content were set for feasible controls. Using the optimal control feeding strategy, glucose concentration and accumulated cellulose conversion reached up to 77.31 g/L and 72.08% in 100 h, which are 108.76% and 37.50% higher than in batch hydrolysis with same amount of enzyme consumption. Solids content in feeding source has a significant interference on system mass transfer. Optimal control is a useful tool for guiding operations in fed-batch and continuous processes as it enables process optimization through clear objective functions and feasible controls. © 2015 Wiley Periodicals, Inc.

  6. Improved pretreatment of lignocellulosic biomass using enzymatically-generated peracetic acid.

    PubMed

    Yin, DeLu Tyler; Jing, Qing; AlDajani, Waleed Wafa; Duncan, Shona; Tschirner, Ulrike; Schilling, Jonathan; Kazlauskas, Romas J

    2011-04-01

    Release of sugars from lignocellulosic biomass is inefficient because lignin, an aromatic polymer, blocks access of enzymes to the sugar polymers. Pretreatments remove lignin and disrupt its structure, thereby enhancing sugar release. In previous work, enzymatically generated peracetic acid was used to pretreat aspen wood. This pretreatment removed 45% of the lignin and the subsequent saccharification released 97% of the sugars remaining after pretreatment. In this paper, the amount of enzyme needed is reduced tenfold using first, an improved enzyme variant that makes twice as much peracetic acid and second, a two-phase reaction to generate the peracetic acid, which allows enzyme reuse. In addition, the eight pretreatment cycles are reduced to only one by increasing the volume of peracetic acid solution and increasing the temperature to 60 °C and the reaction time to 6h. For the pretreatment step, the weight ratio of peracetic acid to wood determines the amount of lignin removed.

  7. Microbial Production of Short Chain Fatty Acids from Lignocellulosic Biomass: Current Processes and Market

    PubMed Central

    Baumann, Ivan

    2016-01-01

    Biological production of organic acids from conversion of biomass derivatives has received increased attention among scientists and engineers and in business because of the attractive properties such as renewability, sustainability, degradability, and versatility. The aim of the present review is to summarize recent research and development of short chain fatty acids production by anaerobic fermentation of nonfood biomass and to evaluate the status and outlook for a sustainable industrial production of such biochemicals. Volatile fatty acids (VFAs) such as acetic acid, propionic acid, and butyric acid have many industrial applications and are currently of global economic interest. The focus is mainly on the utilization of pretreated lignocellulosic plant biomass as substrate (the carbohydrate route) and development of the bacteria and processes that lead to a high and economically feasible production of VFA. The current and developing market for VFA is analyzed focusing on production, prices, and forecasts along with a presentation of the biotechnology companies operating in the market for sustainable biochemicals. Finally, perspectives on taking sustainable product of biochemicals from promise to market introduction are reviewed. PMID:27556042

  8. The effect of Pleurotus ostreatus arabinofuranosidase and its evolved variant in lignocellulosic biomasses conversion.

    PubMed

    Marcolongo, Loredana; Ionata, Elena; La Cara, Francesco; Amore, Antonella; Giacobbe, Simona; Pepe, Olimpia; Faraco, Vincenza

    2014-11-01

    The fungal arabinofuranosidase from Pleurotus ostreatus PoAbf recombinantly expressed in Pichia pastoris rPoAbf and its evolved variant rPoAbf F435Y/Y446F were tested for their effectiveness to enhance the enzymatic saccharification of three lignocellulosic biomasses, namely Arundo donax, corn cobs and brewer's spent grains (BSG), after chemical or chemical-physical pretreatment. All the raw materials were subjected to an alkaline pretreatment by soaking in aqueous ammonia solution whilst the biomass from A. donax was also pretreated by steam explosion. The capability of the wild-type and mutant rPoAbf to increase the fermentable sugars recovery was assessed by using these enzymes in combination with different (hemi)cellulolytic activities. These enzymatic mixtures were either entirely of commercial origin or contained the cellulase from Streptomyces sp. G12 CelStrep recombinantly expressed in Escherichia coli in substitution to the commercial counterparts. The addition of the arabinofuranosidases from P. ostreatus improved the hydrolytic efficiency of the commercial enzymatic cocktails on all the pretreated biomasses. The best results were obtained using the rPoAbf evolved variant and are represented by increases of the xylose recovery up to 56.4%. These data clearly highlight the important role of the accessory hemicellulolytic activities to optimize the xylan bioconversion yields. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. The cost of ethanol production from lignocellulosic biomass -- A comparison of selected alternative processes. Final report

    SciTech Connect

    Grethlein, H.E.; Dill, T.

    1993-04-30

    The purpose of this report is to compare the cost of selected alternative processes for the conversion of lignocellulosic biomass to ethanol. In turn, this information will be used by the ARS/USDA to guide the management of research and development programs in biomass conversion. The report will identify where the cost leverages are for the selected alternatives and what performance parameters need to be achieved to improve the economics. The process alternatives considered here are not exhaustive, but are selected on the basis of having a reasonable potential in improving the economics of producing ethanol from biomass. When other alternatives come under consideration, they should be evaluated by the same methodology used in this report to give fair comparisons of opportunities. A generic plant design is developed for an annual production of 25 million gallons of anhydrous ethanol using corn stover as the model substrate at $30/dry ton. Standard chemical engineering techniques are used to give first order estimates of the capital and operating costs. Following the format of the corn to ethanol plant, there are nine sections to the plant; feed preparation, pretreatment, hydrolysis, fermentation, distillation and dehydration, stillage evaporation, storage and denaturation, utilities, and enzyme production. There are three pretreatment alternatives considered: the AFEX process, the modified AFEX process (which is abbreviated as MAFEX), and the STAKETECH process. These all use enzymatic hydrolysis and so an enzyme production section is included in the plant. The STAKETECH is the only commercially available process among the alternative processes.

  10. Evaluating lignocellulosic biomass, its derivatives, and downstream products with Raman spectroscopy

    SciTech Connect

    Lupoi, Jason S.; Gjersing, Erica; Davis, Mark F.

    2015-04-20

    The creation of fuels, chemicals, and materials from plants can aid in replacing products fabricated from non-renewable energy sources. Before using biomass in downstream applications, it must be characterized to assess chemical traits, such as cellulose, lignin, or lignin monomer content, or the sugars released following an acid or enzymatic hydrolysis. The measurement of these traits allows researchers to gage the recalcitrance of the plants and develop efficient deconstruction strategies to maximize yields. Standard methods for assessing biomass phenotypes often have experimental protocols that limit their use for screening sizeable numbers of plant species. Raman spectroscopy, a non-destructive, non-invasive vibrational spectroscopy technique, is capable of providing qualitative, structural information and quantitative measurements. Applications of Raman spectroscopy have aided in alleviating the constraints of standard methods by coupling spectral data with multivariate analysis to construct models capable of predicting analytes. Hydrolysis and fermentation products, such as glucose and ethanol, can be quantified off-, at-, or on-line. Raman imaging has enabled researchers to develop a visual understanding of reactions, such as different pretreatment strategies, in real-time, while also providing integral chemical information. Finally, this review provides an overview of what Raman spectroscopy is, and how it has been applied to the analysis of whole lignocellulosic biomass, its derivatives, and downstream process monitoring.

  11. Evaluating lignocellulosic biomass, its derivatives, and downstream products with Raman spectroscopy

    DOE PAGES

    Lupoi, Jason S.; Gjersing, Erica; Davis, Mark F.

    2015-04-20

    The creation of fuels, chemicals, and materials from plants can aid in replacing products fabricated from non-renewable energy sources. Before using biomass in downstream applications, it must be characterized to assess chemical traits, such as cellulose, lignin, or lignin monomer content, or the sugars released following an acid or enzymatic hydrolysis. The measurement of these traits allows researchers to gage the recalcitrance of the plants and develop efficient deconstruction strategies to maximize yields. Standard methods for assessing biomass phenotypes often have experimental protocols that limit their use for screening sizeable numbers of plant species. Raman spectroscopy, a non-destructive, non-invasive vibrationalmore » spectroscopy technique, is capable of providing qualitative, structural information and quantitative measurements. Applications of Raman spectroscopy have aided in alleviating the constraints of standard methods by coupling spectral data with multivariate analysis to construct models capable of predicting analytes. Hydrolysis and fermentation products, such as glucose and ethanol, can be quantified off-, at-, or on-line. Raman imaging has enabled researchers to develop a visual understanding of reactions, such as different pretreatment strategies, in real-time, while also providing integral chemical information. Finally, this review provides an overview of what Raman spectroscopy is, and how it has been applied to the analysis of whole lignocellulosic biomass, its derivatives, and downstream process monitoring.« less

  12. Evaluating Lignocellulosic Biomass, Its Derivatives, and Downstream Products with Raman Spectroscopy

    PubMed Central

    Lupoi, Jason S.; Gjersing, Erica; Davis, Mark F.

    2015-01-01

    The creation of fuels, chemicals, and materials from plants can aid in replacing products fabricated from non-renewable energy sources. Before using biomass in downstream applications, it must be characterized to assess chemical traits, such as cellulose, lignin, or lignin monomer content, or the sugars released following an acid or enzymatic hydrolysis. The measurement of these traits allows researchers to gage the recalcitrance of the plants and develop efficient deconstruction strategies to maximize yields. Standard methods for assessing biomass phenotypes often have experimental protocols that limit their use for screening sizeable numbers of plant species. Raman spectroscopy, a non-destructive, non-invasive vibrational spectroscopy technique, is capable of providing qualitative, structural information and quantitative measurements. Applications of Raman spectroscopy have aided in alleviating the constraints of standard methods by coupling spectral data with multivariate analysis to construct models capable of predicting analytes. Hydrolysis and fermentation products, such as glucose and ethanol, can be quantified off-, at-, or on-line. Raman imaging has enabled researchers to develop a visual understanding of reactions, such as different pretreatment strategies, in real-time, while also providing integral chemical information. This review provides an overview of what Raman spectroscopy is, and how it has been applied to the analysis of whole lignocellulosic biomass, its derivatives, and downstream process monitoring. PMID:25941674

  13. Microbial Production of Short Chain Fatty Acids from Lignocellulosic Biomass: Current Processes and Market.

    PubMed

    Baumann, Ivan; Westermann, Peter

    2016-01-01

    Biological production of organic acids from conversion of biomass derivatives has received increased attention among scientists and engineers and in business because of the attractive properties such as renewability, sustainability, degradability, and versatility. The aim of the present review is to summarize recent research and development of short chain fatty acids production by anaerobic fermentation of nonfood biomass and to evaluate the status and outlook for a sustainable industrial production of such biochemicals. Volatile fatty acids (VFAs) such as acetic acid, propionic acid, and butyric acid have many industrial applications and are currently of global economic interest. The focus is mainly on the utilization of pretreated lignocellulosic plant biomass as substrate (the carbohydrate route) and development of the bacteria and processes that lead to a high and economically feasible production of VFA. The current and developing market for VFA is analyzed focusing on production, prices, and forecasts along with a presentation of the biotechnology companies operating in the market for sustainable biochemicals. Finally, perspectives on taking sustainable product of biochemicals from promise to market introduction are reviewed.

  14. Evaluating lignocellulosic biomass, its derivatives, and downstream products with Raman spectroscopy.

    PubMed

    Lupoi, Jason S; Gjersing, Erica; Davis, Mark F

    2015-01-01

    The creation of fuels, chemicals, and materials from plants can aid in replacing products fabricated from non-renewable energy sources. Before using biomass in downstream applications, it must be characterized to assess chemical traits, such as cellulose, lignin, or lignin monomer content, or the sugars released following an acid or enzymatic hydrolysis. The measurement of these traits allows researchers to gage the recalcitrance of the plants and develop efficient deconstruction strategies to maximize yields. Standard methods for assessing biomass phenotypes often have experimental protocols that limit their use for screening sizeable numbers of plant species. Raman spectroscopy, a non-destructive, non-invasive vibrational spectroscopy technique, is capable of providing qualitative, structural information and quantitative measurements. Applications of Raman spectroscopy have aided in alleviating the constraints of standard methods by coupling spectral data with multivariate analysis to construct models capable of predicting analytes. Hydrolysis and fermentation products, such as glucose and ethanol, can be quantified off-, at-, or on-line. Raman imaging has enabled researchers to develop a visual understanding of reactions, such as different pretreatment strategies, in real-time, while also providing integral chemical information. This review provides an overview of what Raman spectroscopy is, and how it has been applied to the analysis of whole lignocellulosic biomass, its derivatives, and downstream process monitoring.

  15. A thermochemical-biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals.

    PubMed

    Shen, Yanwen; Jarboe, Laura; Brown, Robert; Wen, Zhiyou

    2015-12-01

    Thermochemical-biological hybrid processing uses thermochemical decomposition of lignocellulosic biomass to produce a variety of intermediate compounds that can be converted into fuels and chemicals through microbial fermentation. It represents a unique opportunity for biomass conversion as it mitigates some of the deficiencies of conventional biochemical (pretreatment-hydrolysis-fermentation) and thermochemical (pyrolysis or gasification) processing. Thermochemical-biological hybrid processing includes two pathways: (i) pyrolysis/pyrolytic substrate fermentation, and (ii) gasification/syngas fermentation. This paper provides a comprehensive review of these two hybrid processing pathways, including the characteristics of fermentative substrates produced in the thermochemical stage and microbial utilization of these compounds in the fermentation stage. The current challenges of these two biomass conversion pathways include toxicity of the crude pyrolytic substrates, the inhibition of raw syngas contaminants, and the mass-transfer limitations in syngas fermentation. Possible approaches for mitigating substrate toxicities are discussed. The review also provides a summary of the current efforts to commercialize hybrid processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. The prospects of cellulase-producing bacteria for the bioconversion of lignocellulosic biomass

    PubMed Central

    Maki, Miranda; Leung, Kam Tin; Qin, Wensheng

    2009-01-01

    Lignocellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. However, the biorefining process remains economically unfeasible due to a lack of biocatalysts that can overcome costly hurdles such as cooling from high temperature, pumping of oxygen/stirring, and, neutralization from acidic or basic pH. The extreme environmental resistance of bacteria permits screening and isolation of novel cellulases to help overcome these challenges. Rapid, efficient cellulase screening techniques, using cellulase assays and metagenomic libraries, are a must. Rare cellulases with activities on soluble and crystalline cellulose have been isolated from strains of Paenibacillus and Bacillus and shown to have high thermostability and/or activity over a wide pH spectrum. While novel cellulases from strains like Cellulomonas flavigena and Terendinibacter turnerae, produce multifunctional cellulases with broader substrate utilization. These enzymes offer a framework for enhancement of cellulases including: specific activity, thermalstability, or end-product inhibition. In addition, anaerobic bacteria like the clostridia offer potential due to species capable of producing compound multienzyme complexes called cellulosomes. Cellulosomes provide synergy and close proximity of enzymes to substrate, increasing activity towards crystalline cellulose. This has lead to the construction of designer cellulosomes enhanced for specific substrate activity. Furthermore, cellulosome-producing Clostridium thermocellum and its ability to ferment sugars to ethanol; its amenability to co-culture and, recent advances in genetic engineering, offer a promising future in biofuels. The exploitation of bacteria in the search for improved enzymes or strategies provides a means to upgrade feasibility for lignocellulosic biomass conversion, ultimately providing means to a 'greener' technology. PMID:19680472

  17. Facile pretreatment of lignocellulosic biomass at high loadings in room temperature ionic liquids.

    PubMed

    Wu, Hong; Mora-Pale, Mauricio; Miao, Jianjun; Doherty, Thomas V; Linhardt, Robert J; Dordick, Jonathan S

    2011-12-01

    Ionic liquids (ILs) have emerged as attractive solvents for lignocellulosic biomass pretreatment in the production of biofuels and chemical feedstocks. However, the high cost of ILs is a key deterrent to their practical application. Here, we show that acetate based ILs are effective in dramatically reducing the recalcitrance of corn stover toward enzymatic polysaccharide hydrolysis even at loadings of biomass as high as 50% by weight. Under these conditions, the IL serves more as a pretreatment additive rather than a true solvent. Pretreatment of corn stover with 1-ethyl-3-methylimidizolium acetate ([Emim] [OAc]) at 125 ± 5°C for 1 h resulted in a dramatic reduction of cellulose crystallinity (up to 52%) and extraction of lignin (up to 44%). Enzymatic hydrolysis of the IL-treated biomass was performed with a common commercial cellulase/xylanase from Trichoderma reesei and a commercial β-glucosidase, and resulted in fermentable sugar yields of ∼80% for glucose and ∼50% for xylose at corn stover loadings up to 33% (w/w) and 55% and 34% for glucose and xylose, respectively, at 50% (w/w) biomass loading. Similar results were observed for the IL-facilitated pretreatment of switchgrass, poplar, and the highly recalcitrant hardwood, maple. At 4.8% (w/w) corn stover, [Emim][OAc] can be readily reused up to 10 times without removal of extracted components, such as lignin, with no effect on subsequent fermentable sugar yields. A significant reduction in the amount of IL combined with facile recycling has the potential to enable ILs to be used in large-scale biomass pretreatment. Copyright © 2011 Wiley Periodicals, Inc.

  18. Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

    NASA Astrophysics Data System (ADS)

    Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

    2015-02-01

    The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the `greener' technology of second-generation biofuels.

  19. Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

    PubMed Central

    Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

    2015-01-01

    The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the ‘greener' technology of second-generation biofuels. PMID:25641069

  20. An advanced understanding of the specific effects of xylan and surface lignin contents on enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Ju, Xiaohui; Engelhard, Mark; Zhang, Xiao

    2013-03-01

    In this study, chemical pulping techniques were applied to create a set of biomass substrates with intact lignocellulosic fibers and controlled morphological and chemical properties to allow the investigation of the individual effects of xylan and surface lignin content on enzymatic hydrolysis. A high resolution X-ray photoelectron spectroscopy technique was established for quantifying surface lignin content on lignocellulosic biomass substrates. The results from this study show that, apart from its hindrance effect, xylan can facilitate cellulose fibril swelling and thus create more accessible surface area, which improves enzyme and substrate interactions. Surface lignin has a direct impact on enzyme adsorption kinetics and hydrolysis rate. Advanced understanding of xylan and surface lignin effects provides critical information for developing more effective biomass conversion process. Published by Elsevier Ltd.

  1. From lignocellulosic biomass to lactic- and glycolic-acid oligomers: a gram-scale microwave-assisted protocol.

    PubMed

    Carnaroglio, Diego; Tabasso, Silvia; Kwasek, Beata; Bogdal, Dariusz; Gaudino, Emanuela Calcio; Cravotto, Giancarlo

    2015-04-24

    The conversion of lignocellulosic biomass into platform chemicals is the key step in the valorization of agricultural waste. Of the biomass-derived platform chemicals currently produced, lactic acid plays a particularly pivotal role in modern biorefineries as it is a versatile commodity chemical and building block for the synthesis of biodegradable polymers. Microwave-assisted processes that furnish lactic acid avoid harsh depolymerization conditions while cutting down reaction time and energy consumption. We herein report a flash catalytic conversion (2 min) of lignocellulosic biomass into lactic and glycolic acids under microwave irradiation. The batch procedure was successfully adapted to a microwave-assisted flow process (35 mL min(-1) ), with the aim of designing a scalable process with higher productivity. The C2 and C4 units recovered from the depolymerization were directly used as the starting material for a solvent and catalyst-free microwave-assisted polycondensation that afforded oligomers in good yields.

  2. Lignocellulose-Degrading Microbial Communities in Landfill Sites Represent a Repository of Unexplored Biomass-Degrading Diversity

    PubMed Central

    Ransom-Jones, Emma; McCarthy, Alan J.; Haldenby, Sam; Doonan, James

    2017-01-01

    ABSTRACT The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, to address the paucity of information on biomass-degrading microbial diversity beyond the gastrointestinal tract, cellulose (cotton) “baits” were incubated in landfill leachate microcosms to enrich the landfill cellulolytic microbial community for taxonomic and functional characterization. Metagenome and 16S rRNA gene amplicon sequencing demonstrated the dominance of Firmicutes, Bacteroidetes, Spirochaetes, and Fibrobacteres in the landfill cellulolytic community. Functional metagenome analysis revealed 8,371 carbohydrate active enzymes (CAZymes) belonging to 244 CAZyme families. In addition to observing biomass-degrading enzymes of anaerobic bacterial “cellulosome” systems of members of the Firmicutes, we report the first detection of the Fibrobacter cellulase system and the Bacteroidetes polysaccharide utilization locus (PUL) in landfill sites. These data provide evidence for the presence of multiple mechanisms of biomass degradation in the landfill microbiome and highlight the extraordinary functional diversity of landfill microorganisms as a rich source of biomass-degrading enzymes of potential biotechnological significance. IMPORTANCE The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have

  3. Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose.

    PubMed

    Gabhane, Jagdish; William, S P M Prince; Vaidya, Atul N; Das, Sera; Wate, Satish R

    2015-06-01

    A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose

    SciTech Connect

    Gabhane, Jagdish; William, S.P.M. Prince; Vaidya, Atul N.; Das, Sera; Wate, Satish R.

    2015-06-15

    Highlights: • SAAP is an efficient and economic means of pretreatment. • SAAP was found to be efficient in lignin and hemicellulose removal. • SAAP enhanced the enzymatic hydrolysis. • FTIR, XRD and SEM provided vivid understanding about the mode of action of SAAP. • Mass balance closer of 98% for pretreated GB confirmed the reliability of SAAP. - Abstract: A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment.

  5. Survey of renewable chemicals produced from lignocellulosic biomass during ionic liquid pretreatment

    PubMed Central

    2013-01-01

    Background Lignin is often overlooked in the valorization of lignocellulosic biomass, but lignin-based materials and chemicals represent potential value-added products for biorefineries that could significantly improve the economics of a biorefinery. Fluctuating crude oil prices and changing fuel specifications are some of the driving factors to develop new technologies that could be used to convert polymeric lignin into low molecular weight lignin and or monomeric aromatic feedstocks to assist in the displacement of the current products associated with the conversion of a whole barrel of oil. We present an approach to produce these chemicals based on the selective breakdown of lignin during ionic liquid pretreatment. Results The lignin breakdown products generated are found to be dependent on the starting biomass, and significant levels were generated on dissolution at 160°C for 6 hrs. Guaiacol was produced on dissolution of biomass and technical lignins. Vanillin was produced on dissolution of kraft lignin and eucalytpus. Syringol and allyl guaiacol were the major products observed on dissolution of switchgrass and pine, respectively, whereas syringol and allyl syringol were obtained by dissolution of eucalyptus. Furthermore, it was observed that different lignin-derived products could be generated by tuning the process conditions. Conclusions We have developed an ionic liquid based process that depolymerizes lignin and converts the low molecular weight lignin fractions into a variety of renewable chemicals from biomass. The generated chemicals (phenols, guaiacols, syringols, eugenol, catechols), their oxidized products (vanillin, vanillic acid, syringaldehyde) and their easily derivatized hydrocarbons (benzene, toluene, xylene, styrene, biphenyls and cyclohexane) already have relatively high market value as commodity and specialty chemicals, green building materials, nylons, and resins. PMID:23356589

  6. Techno-Economic Basis for Coproduct Manufacturing To Enable Hydrocarbon Fuel Production from Lignocellulosic Biomass

    SciTech Connect

    Biddy, Mary J.; Davis, Ryan; Humbird, David; Tao, Ling; Dowe, Nancy; Guarnieri, Michael T.; Linger, Jeffrey G.; Karp, Eric M.; Salvachua, Davinia; Vardon, Derek R.; Beckham, Gregg T.

    2016-06-06

    Biorefinery process development relies on techno-economic analysis (TEA) to identify primary cost drivers, prioritize research directions, and mitigate technical risk for scale-up through development of detailed process designs. Here, we conduct TEA of a model 2000 dry metric ton-per-day lignocellulosic biorefinery that employs a two-step pretreatment and enzymatic hydrolysis to produce biomass-derived sugars, followed by biological lipid production, lipid recovery, and catalytic hydrotreating to produce renewable diesel blendstock (RDB). On the basis of projected near-term technical feasibility of these steps, we predict that RDB could be produced at a minimum fuel selling price (MFSP) of USD $9.55/gasoline-gallon-equivalent (GGE), predicated on the need for improvements in the lipid productivity and yield beyond current benchmark performance. This cost is significant given the limitations in scale and high costs for aerobic cultivation of oleaginous microbes and subsequent lipid extraction/recovery. In light of this predicted cost, we developed an alternative pathway which demonstrates that RDB costs could be substantially reduced in the near term if upgradeable fractions of biomass, in this case hemicellulose-derived sugars, are diverted to coproducts of sufficient value and market size; here, we use succinic acid as an example coproduct. The coproduction model predicts an MFSP of USD $5.28/GGE when leaving conversion and yield parameters unchanged for the fuel production pathway, leading to a change in biorefinery RDB capacity from 24 to 15 MM GGE/year and 0.13 MM tons of succinic acid per year. Additional analysis demonstrates that beyond the near-term projections assumed in the models here, further reductions in the MFSP toward $2-3/GGE (which would be competitive with fossil-based hydrocarbon fuels) are possible with additional transformational improvements in the fuel and coproduct trains, especially in terms of carbon efficiency to both fuels and

  7. Microbial inhibitors: formation and effects on acetone-butanol-ethanol fermentation of lignocellulosic biomass.

    PubMed

    Baral, Nawa Raj; Shah, Ajay

    2014-11-01

    Biobutanol is a promising biofuel due to the close resemblance of its fuel properties to gasoline, and it is produced via acetone-butanol-ethanol (ABE) fermentation using Clostridium species. However, lignin in the crystalline structure of the lignin-cellulose-hemicellulose biomass complex is not readily consumed by the Clostridium; thus, pretreatment is required to degrade this complex. During pretreatment, some fractions of cellulose and hemicellulose are converted into fermentable sugars, which are further converted to ABE. However, a major setback resulting from common pretreatment processes is the formation of sugar and lignin degradation compounds, including weak acids, furan derivatives, and phenolic compounds, which have inhibitory effects on the Clostridium. In addition, butanol concentration above 13 g/L in the fermentation broth is itself toxic to most Clostridium strain(s). This review summarizes the current state-of-the-art knowledge on the formation of microbial inhibitors during the most common lignocellulosic biomass pretreatment processes. Metabolic effects of inhibitors and their impacts on ABE production, as well as potential solutions for reducing inhibitor formation, such as optimizing pretreatment process parameters, using inhibitor tolerant strain(s) with high butanol yield ability, continuously recovering butanol during ABE fermentation, and adopting consolidated bioprocessing, are also discussed.

  8. Co-pyrolysis of lignocellulosic biomass and microalgae: Products characteristics and interaction effect.

    PubMed

    Chen, Wei; Chen, Yingquan; Yang, Haiping; Xia, Mingwei; Li, Kaixu; Chen, Xu; Chen, Hanping

    2017-09-06

    Co-pyrolysis of biomass has a potential to change the quality of pyrolytic bio-oil. In this work, co-pyrolysis of bamboo, a typical lignocellulosic biomass, and Nannochloropsis sp. (NS), a microalgae, was carried out in a fixed bed reactor at a range of mixing ratio of NS and bamboo, to find out whether the quality of pyrolytic bio-oil was improved. A significant improvement on bio-oil after co-pyrolysis of bamboo and NS was observed that bio-oil yield increased up to 66.63wt% (at 1:1) and the content of long-chain fatty acids in bio-oil also dramatically increased (the maximum up to 50.92% (13.57wt%) at 1:1) whereas acetic acid, O-containing species, and N-containing compounds decreased greatly. Nitrogen transformation mechanism during co-pyrolysis also was explored. Results showed that nitrogen in microalgae preferred to transform into solid char and gas phase during co-pyrolysis, while more pyrrolic-N and quaternary-N generated with diminishing protein-N and pyridinic-N in char. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Influence of the crystalline structure of cellulose on the production of ethanol from lignocellulose biomass

    NASA Astrophysics Data System (ADS)

    Smuga-Kogut, Małgorzata; Zgórska, Kazimiera; Szymanowska-Powałowska, Daria

    2016-01-01

    In recent years, much attention has been devoted to the possibility of using lignocellulosic biomass for energy. Bioethanol is a promising substitute for conventional fossil fuels and can be produced from straw and wood biomass. Therefore, the aim of this paper was to investigate the effect of 1-ethyl-3-methylimidazolium pretreatment on the structure of cellulose and the acquisition of reducing sugars and bioethanol from cellulosic materials. Material used in the study was rye straw and microcrystalline cellulose subjected to ionic liquid 1-ethyl-3-methylimidazolium pretreatment. The morphology of cellulose fibres in rye straw and microcrystalline cellulose was imaged prior to and after ionic liquid pretreatment. Solutions of ionic liquid-treated and untreated cellulosic materials were subjected to enzymatic hydrolysis in order to obtain reducing sugars, which constituted a substrate for alcoholic fermentation. An influence of the ionic liquid on the cellulose structure, accumulation of reducing sugars in the process of hydrolysis of this material, and an increase in ethanol amount after fermentation was observed. The ionic liquid did not affect cellulolytic enzymes negatively and did not inhibit yeast activity. The amount of reducing sugars and ethyl alcohol was higher in samples purified with 1-ethyl-3-methy-limidazolium acetate. A change in the supramolecular structure of cellulose induced by the ionic liquid was also observed.

  10. Temperature sensitivity of cellulase adsorption on lignin and its impact on enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Zheng, Yingfu; Zhang, Songping; Miao, Shida; Su, Zhiguo; Wang, Ping

    2013-07-10

    Unproductive enzyme adsorption is an important factor in addition to steric hindrance of lignin that limits the enzymatic hydrolysis of lignocellulosic biomass. While both are important factors, enzymatic hydrolysis of pretreated biomass is most likely conducted in the presence of certain amount of lignin residues that may not necessarily present accessibility hindrance, but can competitively absorb the enzyme. This paper presents a study with purified lignin samples to elucidate the role of unproductive enzyme adsorption. It appeared that lignin adsorbed cellulase quickly at 4 °C with adsorption equilibrium reached within 1h, similar to that observed for crystalline cellulose. Increasing temperature to 50 °C (typical hydrolytic reaction condition) facilitated the rate of cellulase adsorption on cellulose with a peak of adsorption reached at 0.25 h; however, adsorption on lignin was surprisingly slower and took over 12h to reach equilibrium, which was accompanied with a 10-fold increase in adsorption capacity. Despite the high adsorption capacity of lignin (which is comparable to that of cellulose) at 50 °C, the presence of added lignin imposed only minimal impact on the enzyme apparent activity, most likely due to the slow adsorption kinetics of lignin.

  11. Kinetics of glucose decomposition during dilute-acid hydrolysis of lignocellulosic biomass.

    PubMed

    Xiang, Qian; Lee, Yong Y; Torget, Robert W

    2004-01-01

    Recent research work in-house both at Auburn University and National Renewable Energy Laboratory has demonstrated that extremely low concentrations of acid (e.g., 0.05-0.2 wt% sulfuric acid) and high temperatures (e.g., 200-230 degrees C) are reaction conditions that can be effectively applied for hydrolysis of the cellulosic component of biomass. These conditions are far from those of the conventional dilute-acid hydrolysis processes, and the kinetic data for glucose decomposition are not currently available. We investigated the kinetics of glucose decomposition covering pH values of 1.5-2.2 and temperatures of 180-230 degrees C using glass ampoule reactors. The primary factors controlling glucose decomposition are the reaction medium, acid concentration, and temperature. Based on the experimental data, a kinetic model was developed and the best-fit kinetic parameters were determined. However, a consistent discrepancy in the rate of glucose disappearance was found between that of the model based on pure glucose data and that observed during the actual process of lignocellulosic biomass hydrolysis. This was taken as an indication that glucose recombines with acid-soluble lignin during the hydrolysis process, and this conclusion was incorporated accordingly into the overall model of glucose decomposition.

  12. High-solids biphasic CO2-H2O pretreatment of lignocellulosic biomass.

    PubMed

    Luterbacher, Jeremy S; Tester, Jefferson W; Walker, Larry P

    2010-10-15

    A high pressure (200 bar) CO(2)-H(2)O process was developed for pretreating lignocellulosic biomass at high-solid contents, while minimizing chemical inputs. Hardwood was pretreated at 20 and 40 (wt.%) solids. Switchgrass, corn stover, big bluestem, and mixed perennial grasses (a co-culture of big bluestem and switchgrass) were pretreated at 40 (wt.%) solids. Operating temperatures ranged from 150 to 250 degrees C, and residence times from 20 s to 60 min. At these conditions a biphasic mixture of an H(2)O-rich liquid (hydrothermal) phase and a CO(2)-rich supercritical phase coexist. Following pretreatment, samples were then enzymatically hydrolyzed. Total yields, defined as the fraction of the theoretical maximum, were determined for glucose, hemicellulose sugars, and two degradation products: furfural and 5-hydroxymethylfurfural. Response surfaces of yield as a function of temperature and residence time were compared for different moisture contents and biomass species. Pretreatment at 170 degrees C for 60 min gave glucose yields of 77%, 73%, and 68% for 20 and 40 (wt.%) solids mixed hardwood and mixed perennial grasses, respectively. Pretreatment at 160 degrees C for 60 min gave glucan to glucose yields of 81% for switchgrass and 85% for corn stover.

  13. Conversion of raw lignocellulosic biomass into branched long-chain alkanes through three tandem steps.

    PubMed

    Li, Chunrui; Ding, Daqian; Xia, Qineng; Liu, Xiaohui; Wang, Yanqin

    2016-07-07

    Synthesis of branched long-chain alkanes from renewable biomass has attracted intensive interest in recent years, but the feedstock for this synthesis is restricted to platform chemicals. Here, we develop an effective and energy-efficient process to convert raw lignocellulosic biomass (e.g., corncob) into branched diesel-range alkanes through three tandem steps for the first time. Furfural and isopropyl levulinate (LA ester) were prepared from hemicellulose and cellulose fractions of corncob in toluene/water biphasic system with added isopropanol, which was followed by double aldol condensation of furfural with LA ester into C15 oxygenates and the final hydrodeoxygenation of C15 oxygenates into branched long-chain alkanes. The core point of this tandem process is the addition of isopropanol in the first step, which enables the spontaneous transfer of levulinic acid (LA) into the toluene phase in the form of LA ester through esterification, resulting in LA ester co-existing with furfural in the same phase, which is the basis for double aldol condensation in the toluene phase. Moreover, the acidic aqueous phase and toluene can be reused and the residues, including lignin and humins in aqueous phase, can be separated and carbonized to porous carbon materials.

  14. Chloroplast-derived enzyme cocktails hydrolyse lignocellulosic biomass and release fermentable sugars.

    PubMed

    Verma, Dheeraj; Kanagaraj, Anderson; Jin, Shuangxia; Singh, Nameirakpam D; Kolattukudy, Pappachan E; Daniell, Henry

    2010-04-01

    It is widely recognized that biofuel production from lignocellulosic materials is limited by inadequate technology to efficiently and economically release fermentable sugars from the complex multi-polymeric raw materials. Therefore, endoglucanases, exoglucanase, pectate lyases, cutinase, swollenin, xylanase, acetyl xylan esterase, beta glucosidase and lipase genes from bacteria or fungi were expressed in Escherichia coli or tobacco chloroplasts. A PCR-based method was used to clone genes without introns from Trichoderma reesei genomic DNA. Homoplasmic transplastomic lines showed normal phenotype and were fertile. Based on observed expression levels, up to 49, 64 and 10, 751 million units of pectate lyases or endoglucanase can be produced annually, per acre of tobacco. Plant production cost of endoglucanase is 3100-fold, and pectate lyase is 1057 or 1480-fold lower than the same recombinant enzymes sold commercially, produced via fermentation. Chloroplast-derived enzymes had higher temperature stability and wider pH optima than enzymes expressed in E. coli. Plant crude-extracts showed higher enzyme activity than E. coli with increasing protein concentration, demonstrating their direct utility without purification. Addition of E. coli extracts to the chloroplast-derived enzymes significantly decreased their activity. Chloroplast-derived crude-extract enzyme cocktails yielded more (up to 3625%) glucose from filter paper, pine wood or citrus peel than commercial cocktails. Furthermore, pectate lyase transplastomic plants showed enhanced resistance to Erwina soft rot. This is the first report of using plant-derived enzyme cocktails for production of fermentable sugars from lignocellulosic biomass. Limitations of higher cost and lower production capacity of fermentation systems are addressed by chloroplast-derived enzyme cocktails.

  15. Chloroplast-derived enzyme cocktails hydrolyse lignocellulosic biomass and release fermentable sugars

    PubMed Central

    Verma, Dheeraj; Kanagaraj, Anderson; Jin, Shuangxia; Singh, Nameirakpam D.; Kolattukudy, Pappachan E; Daniell, Henry

    2009-01-01

    Summary It is widely recognized that biofuel production from lignocellulosic materials is limited by inadequate technology to efficiently and economically release fermentable sugars from the complex multi-polymeric raw materials. Therefore, endoglucanases, exoglucanase, pectate lyases, cutinase, swollenin, xylanase, acetyl xylan esterase, beta glucosidase and lipase genes from bacteria or fungi were expressed in E. coli or tobacco chloroplasts. A PCR based method was used to clone genes without introns from Trichoderma reesei genomic DNA. Homoplasmic transplastomic lines showed normal phenotype and were fertile. Based on observed expression levels, up to 49, 64 and 10,751 million units of pectate lyases or endoglucanase can be produced annually, per acre of tobacco. Plant production cost of endoglucanase is 3,100-fold and pectate lyase is 1,057 or 1,480 fold lower than the same recombinant enzymes sold commercially, produced via fermentation. Chloroplast-derived enzymes had higher temperature stability and wider pH optima than enzymes expressed in E. coli. Plant crude-extracts showed higher enzyme activity than E. coli with increasing protein concentration, demonstrating their direct utility without purification. Addition of E. coli extracts to the chloroplast-derived enzymes significantly decreased their activity. Chloroplast-derived crude-extract enzyme cocktails yielded more (up to 3,625%) glucose from filter paper, pine wood or citrus peel than commercial cocktails. Furthermore, pectate lyase transplastomic plants showed enhanced resistance to Erwina soft rot. This is the first report of using plant-derived enzyme cocktails for production of fermentable sugars from lignocellulosic biomass. Limitations of higher cost and lower production capacity of fermentation systems are addressed by chloroplast-derived enzyme cocktails. PMID:20070870

  16. Post-genomic analyses of fungal lignocellulosic biomass degradation reveal the unexpected potential of the plant pathogen Ustilago maydis

    PubMed Central

    2012-01-01

    Background Filamentous fungi are potent biomass degraders due to their ability to thrive in ligno(hemi)cellulose-rich environments. During the last decade, fungal genome sequencing initiatives have yielded abundant information on the genes that are putatively involved in lignocellulose degradation. At present, additional experimental studies are essential to provide insights into the fungal secreted enzymatic pools involved in lignocellulose degradation. Results In this study, we performed a wide analysis of 20 filamentous fungi for which genomic data are available to investigate their biomass-hydrolysis potential. A comparison of fungal genomes and secretomes using enzyme activity profiling revealed discrepancies in carbohydrate active enzymes (CAZymes) sets dedicated to plant cell wall. Investigation of the contribution made by each secretome to the saccharification of wheat straw demonstrated that most of them individually supplemented the industrial Trichoderma reesei CL847 enzymatic cocktail. Unexpectedly, the most striking effect was obtained with the phytopathogen Ustilago maydis that improved the release of total sugars by 57% and of glucose by 22%. Proteomic analyses of the best-performing secretomes indicated a specific enzymatic mechanism of U. maydis that is likely to involve oxido-reductases and hemicellulases. Conclusion This study provides insight into the lignocellulose-degradation mechanisms by filamentous fungi and allows for the identification of a number of enzymes that are potentially useful to further improve the industrial lignocellulose bioconversion process. PMID:22300648

  17. A Novel NADPH-Dependent Aldehyde Reductase Gene from Saccharomyces cerevisiae NRRL Y-12632 Involved in the Detoxification of Aldehyde Inhibitors Derived from Lignocellulosic Biomass Conversion

    USDA-ARS?s Scientific Manuscript database

    Aldehyde inhibitors such as furfural, 5-hydroxymethylfurfural (HMF), anisaldehyde, benzaldehyde, cinnamaldehyde, and phenylaldehyde are commonly generated during lignocellulosic biomass conversion process for low-cost cellulosic ethanol production that interferes with subsequent microbial growth and...

  18. Using FTIR spectroscopy to model alkaline pretreatment and enzymatic saccharification of six lignocellulosic biomasses.

    PubMed

    Sills, Deborah L; Gossett, James M

    2012-04-01

    Fourier transform infrared, attenuated total reflectance (FTIR-ATR) spectroscopy, combined with partial least squares (PLS) regression, accurately predicted solubilization of plant cell wall constituents and NaOH consumption through pretreatment, and overall sugar productions from combined pretreatment and enzymatic hydrolysis. PLS regression models were constructed by correlating FTIR spectra of six raw biomasses (two switchgrass cultivars, big bluestem grass, a low-impact, high-diversity mixture of prairie biomasses, mixed hardwood, and corn stover), plus alkali loading in pretreatment, to nine dependent variables: glucose, xylose, lignin, and total solids solubilized in pretreatment; NaOH consumed in pretreatment; and overall glucose and xylose conversions and yields from combined pretreatment and enzymatic hydrolysis. PLS models predicted the dependent variables with the following values of coefficient of determination for cross-validation (Q²): 0.86 for glucose, 0.90 for xylose, 0.79 for lignin, and 0.85 for total solids solubilized in pretreatment; 0.83 for alkali consumption; 0.93 for glucose conversion, 0.94 for xylose conversion, and 0.88 for glucose and xylose yields. The sugar yield models are noteworthy for their ability to predict overall saccharification through combined pretreatment and enzymatic hydrolysis per mass dry untreated solids without a priori knowledge of the composition of solids. All wavenumbers with significant variable-important-for-projection (VIP) scores have been attributed to chemical features of lignocellulose, demonstrating the models were based on real chemical information. These models suggest that PLS regression can be applied to FTIR-ATR spectra of raw biomasses to rapidly predict effects of pretreatment on solids and on subsequent enzymatic hydrolysis. Copyright © 2011 Wiley Periodicals, Inc.

  19. Comparative lipid production by oleaginous yeasts in hydrolyzates of lignocellulosic biomass and process strategy for high titers.

    PubMed

    Slininger, Patricia J; Dien, Bruce S; Kurtzman, Cletus P; Moser, Bryan R; Bakota, Erica L; Thompson, Stephanie R; O'Bryan, Patricia J; Cotta, Michael A; Balan, Venkatesh; Jin, Mingjie; Sousa, Leonardo da Costa; Dale, Bruce E

    2016-08-01

    Oleaginous yeasts can convert sugars to lipids with fatty acid profiles similar to those of vegetable oils, making them attractive for production of biodiesel. Lignocellulosic biomass is an attractive source of sugars for yeast lipid production because it is abundant, potentially low cost, and renewable. However, lignocellulosic hydrolyzates are laden with byproducts which inhibit microbial growth and metabolism. With the goal of identifying oleaginous yeast strains able to convert plant biomass to lipids, we screened 32 strains from the ARS Culture Collection, Peoria, IL to identify four robust strains able to produce high lipid concentrations from both acid and base-pretreated biomass. The screening was arranged in two tiers using undetoxified enzyme hydrolyzates of ammonia fiber expansion (AFEX)-pretreated cornstover as the primary screening medium and acid-pretreated switch grass as the secondary screening medium applied to strains passing the primary screen. Hydrolyzates were prepared at ∼18-20% solids loading to provide ∼110 g/L sugars at ∼56:39:5 mass ratio glucose:xylose:arabinose. A two stage process boosting the molar C:N ratio from 60 to well above 400 in undetoxified switchgrass hydrolyzate was optimized with respect to nitrogen source, C:N, and carbon loading. Using this process three strains were able to consume acetic acid and nearly all available sugars to accumulate 50-65% of cell biomass as lipid (w/w), to produce 25-30 g/L lipid at 0.12-0.22 g/L/h and 0.13-0.15 g/g or 39-45% of the theoretical yield at pH 6 and 7, a performance unprecedented in lignocellulosic hydrolyzates. Three of the top strains have not previously been reported for the bioconversion of lignocellulose to lipids. The successful identification and development of top-performing lipid-producing yeast in lignocellulose hydrolyzates is expected to advance the economic feasibility of high quality biodiesel and jet fuels from renewable biomass, expanding the market

  20. Synergistic effect on thermal behavior during co-pyrolysis of lignocellulosic biomass model components blend with bituminous coal.

    PubMed

    Wu, Zhiqiang; Wang, Shuzhong; Zhao, Jun; Chen, Lin; Meng, Haiyu

    2014-10-01

    Co-thermochemical conversion of lignocellulosic biomass and coal has been investigated as an effective way to reduce the carbon footprint. Successful evaluating on thermal behavior of the co-pyrolysis is prerequisite for predicting performance and optimizing efficiency of this process. In this paper, pyrolysis and kinetics characteristics of three kinds of lignocellulosic biomass model components (cellulose, hemicellulose, and lignin) blended with a kind of Chinese bituminous coal were explored by thermogravimetric analyzer and Kissinger-Akahira-Sunose method. The results indicated that the addition of model compounds had different synergistic effects on thermal behavior of the bituminous coal. The cellulose showed positive synergistic effects on the thermal decomposition of the coal bituminous coal with lower char yield than calculated value. For hemicellulose and lignin, whether positive or negative synergistic was related to the mixed ratio and temperature range. The distribution of the average activation energy values for the mixtures showed nonadditivity performance.

  1. Transcriptomic analysis of lignocellulosic biomass degradation by the anaerobic fungal isolate Orpinomyces sp. strain C1A.

    PubMed

    Couger, M B; Youssef, Noha H; Struchtemeyer, Christopher G; Liggenstoffer, Audra S; Elshahed, Mostafa S

    2015-01-01

    Anaerobic fungi reside in the rumen and alimentary tract of herbivores where they play an important role in the digestion of ingested plant biomass. The anaerobic fungal isolate Orpinomyces sp. strain C1A is an efficient biomass degrader, capable of simultaneous saccharification and fermentation of the cellulosic and hemicellulosic fractions in multiple types of lignocellulosic biomass. To understand the mechanistic and regulatory basis of biomass deconstruction in anaerobic fungi, we analyzed the transcriptomic profiles of C1A when grown on four different types of lignocellulosic biomass (alfalfa, energy cane, corn stover, and sorghum) versus a soluble sugar monomer (glucose). A total of 468.2 million reads (70.2 Gb) were generated and assembled into 27,506 distinct transcripts. CAZyme transcripts identified included 385, 246, and 44 transcripts belonging to 44, 13, and 8 different glycoside hydrolases (GH), carbohydrate esterases, and polysaccharide lyases families, respectively. Examination of CAZyme transcriptional patterns indicates that strain C1A constitutively transcribes a high baseline level of CAZyme transcripts on glucose. Although growth on lignocellulosic biomass substrates was associated with a significant increase in transcriptional levels in few GH families, including the highly transcribed GH1 β-glucosidase, GH6 cellobiohydrolase, and GH9 endoglucanase, the transcriptional levels of the majority of CAZyme families and transcripts were not significantly altered in glucose-grown versus lignocellulosic biomass-grown cultures. Further, strain C1A co-transcribes multiple functionally redundant enzymes for cellulose and hemicellulose saccharification that are mechanistically and structurally distinct. Analysis of fungal dockerin domain-containing transcripts strongly suggests that anaerobic fungal cellulosomes represent distinct catalytic units capable of independently attacking and converting intact plant fibers to sugar monomers. Collectively, these

  2. Powerful peracetic acid-ionic liquid pretreatment process for the efficient chemical hydrolysis of lignocellulosic biomass.

    PubMed

    Uju; Goto, Masahiro; Kamiya, Noriho

    2016-08-01

    The aim of this work was to design a new method for the efficient saccharification of lignocellulosic biomass (LB) using a combination of peracetic acid (PAA) pretreatment with ionic liquid (IL)-HCl hydrolysis. The pretreatment of LBs with PAA disrupted the lignin fractions, enhanced the dissolution of LB and led to a significant increase in the initial rate of the IL-HCl hydrolysis. The pretreatment of Bagasse with PAA prior to its 1-buthyl-3-methylimidazolium chloride ([Bmim][Cl])-HCl hydrolysis, led to an improvement in the cellulose conversion from 20% to 70% in 1.5h. Interestingly, the 1-buthyl-3-methylpyridium chloride ([Bmpy][Cl])-HCl hydrolysis of Bagasse gave a cellulose conversion greater than 80%, with or without the PAA pretreatment. For LB derived from seaweed waste, the cellulose conversion reached 98% in 1h. The strong hydrolysis power of [Bmpy][Cl] was attributed to its ability to transform cellulose I to II, and lowering the degree of polymerization of cellulose.

  3. Sequential operation of a hybrid anaerobic reactor using a lignocellulosic biomass as biofilm support.

    PubMed

    Wahab, Mohamed Ali; Habouzit, Frédéric; Bernet, Nicolas; Steyer, Jean-Philippe; Jedidi, Naceur; Escudié, Renaud

    2014-11-01

    Agro-industries are facing many economic and environmental problems associated with seasonal generation of liquid and solid waste. In order to reduce treatment costs and to cope with seasonal variation, we have developed a hybrid anaerobic reactor operated sequentially by using lignocellulosic biomass (LB) as biofilm carrier support. Six LBs were tested to evaluate the treatment performance during a succession of two start-up periods, separated by a non-feeding period. After a short acclimation phase of several days, all the reactors succeeded in starting-up in less than 1month to reach an organic loading rate of 25gCODL(-1)d(-1). In addition, they restarted-up successfully in only 15days after a 3month non-feeding period, indicating that biofilms conserved their biological activities during this last phase. As a consequence, the use of LB as a biofilm support gives the potential to sustain seasonal variations of wastewater loads for industrial application. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Deconstruction of lignocellulosic biomass with hydrated cerium (III) chloride in water and ethanol

    DOE PAGES

    Akalin, Mehmet K.; Das, Parthapratim; Alper, Koray; ...

    2017-08-08

    Lignocellulosic biomass was decomposed to produce crude bio-oil in water and ethanol using hydrated cerium (III) chloride as a catalyst. Use of the catalyst affected not only the yield of crude bio-oil but also the composition of bio-crude for both water and ethanol. The catalyst had a detrimental effect on the crude bio-oil yields obtained from water processing for all runs. However, in ethanol, use of the catalyst improved the crude bio-oil yields in all tested runs. The solid residue yields decreased with the catalyst use in the runs with water but increased in all studies with ethanol, except thosemore » with the shortest tested residence time of 10 min. The highest crude bio-oil yield of 48.2 wt% was obtained at 300 °C using 5 mmol of hydrated cerium (III) chloride at a residence time of 90 min in ethanol. The heating values of the crude bio-oils increased with the catalyst use for both water and ethanol processing. In conclusion, the highest heating value of 33.3 MJ kg–1 was obtained with hydrated cerium (III) chloride at 300 °C and a residence time of 120 min.« less

  5. Development of minimal enzyme cocktails for hydrolysis of sulfite-pulped lignocellulosic biomass.

    PubMed

    Chylenski, Piotr; Forsberg, Zarah; Ståhlberg, Jerry; Várnai, Anikó; Lersch, Martin; Bengtsson, Oskar; Sæbø, Solve; Horn, Svein Jarle; Eijsink, Vincent G H

    2017-03-20

    Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8mg/g glucan, whereas almost 100% conversion was achieved at 16mg/g. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Universal fractionation of lignin–carbohydrate complexes (LCCs) from lignocellulosic biomass: an example using spruce wood

    PubMed Central

    Du, Xueyu; Gellerstedt, Goran; Li, Jiebing

    2014-01-01

    SUMMARY It is of both theoretical and practical importance to develop a universally applicable approach for the fractionation and sensitive lignin characterization of lignin–carbohydrate complexes (LCCs) from all types of lignocellulosic biomass, both natively and after various types of processing. In the present study, a previously reported fractionation approach that is applicable for eucalyptus (hardwood) and flax (non-wood) was further improved by introducing an additional step of barium hydroxide precipitation to isolate the mannan-enriched LCC (glucomannan-lignin, GML), in order to suit softwood species as well. Spruce wood was used as the softwood sample. As indicated by the recovery yield and composition analysis, all of the lignin was recovered in three LCC fractions: a glucan-enriched fraction (glucan-lignin, GL), a mannan-enriched fraction (GML) and a xylan-enriched fraction (xylan-lignin, XL). All of the LCCs had high molecular masses and were insoluble or barely soluble in a dioxane/water solution. Carbohydrate and lignin signals were observed in 1H NMR, 13C CP-MAS NMR and normal- or high-sensitivity 2D HSQC NMR analyses. The carbohydrate and lignin constituents in each LCC fraction are therefore believed to be chemically bonded rather than physically mixed with one another. The three LCC fractions were found to be distinctly different from each other in terms of their lignin structures, as revealed by highly sensitive analyses by thioacidolysis-GC, thioacidolysis-SEC and pyrolysis-GC. PMID:23332001

  7. Co-liquefaction of microalgae and lignocellulosic biomass in subcritical water.

    PubMed

    Gai, Chao; Li, Yi; Peng, Nana; Fan, Aonan; Liu, Zhengang

    2015-06-01

    This study investigated co-liquefaction of microalgae (Chlorella pyrenoidosa, CP) and lignocellulosic biomass (Rice husk, RH) in subcritical water for bio-oil production. The effects of liquefaction temperature (200-350°C), residence time (10-90min), solid concentration (10-30wt.%) and mass ratio of CP/RH on product distribution were investigated. The results showed that the highest yield of bio-crude oils at the combination of 50% CP with 50% RH was obtained at 300°C temperature, 60min residence time and 20wt.% solid concentration. The oil yields increased gradually with the increased mass ratio of CP/RH. The major compounds identified in bio-crude oils from hydrothermal liquefaction (HTL) of RH were cyclic oxygenates (20.62%), followed by esters, ketones and alcohols (17.19%). As for CP, the main components were straight & branched amides (28.38%). A synergistic interaction was observed between CP and RH during co-liquefaction, resulting in decreased acidity and nitrogen content of bio-crude oils. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Metabolic engineering of Caldicellulosiruptor bescii yields increased hydrogen production from lignocellulosic biomass

    SciTech Connect

    Cha, Minseok; Chung, Daehwan; Elkins, James G; Guss, Adam M; Westpheling, Janet

    2013-01-01

    Background: Members of the anaerobic thermophilic bacterial genus Caldicellulosiruptor are emerging candidates for consolidated bioprocessing (CBP) because they are capable of efficiently growing on biomass without conventional pretreatment. C. bescii produces primarily lactate, acetate and hydrogen as fermentation products, and while some Caldicellulosiruptor strains produce small amounts of ethanol C. bescii does not, making it an attractive background to examine the effects of metabolic engineering. The recent development of methods for genetic manipulation has set the stage for rational engineering of this genus for improved biofuel production. Here, we report the first targeted gene deletion, the gene encoding lactate dehydrogenase (ldh), for metabolic engineering of a member of this genus. Results: A deletion of the C. bescii L-lactate dehydrogenase gene (ldh) was constructed on a non-replicating plasmid and introduced into the C. bescii chromosome by marker replacement. The resulting strain failed to produce detectable levels of lactate from cellobiose and maltose, instead increasing production of acetate and H2 by 21-34% relative to the wild type and pyrFA parent strains. The same phenotype was observed on a real-world substrate switchgrass (Panicum virgatum). Furthermore, the ldh deletion strain grew to a higher maximum optical density than the wild type on maltose and cellobiose, consistent with the prediction that the mutant would gain additional ATP with increased acetate production. Conclusions: Deletion of ldh in C. bescii is the first use of recently developed genetic methods for metabolic engineering of these bacteria. This deletion resulted in a redirection of electron flow from production of lactate to acetate and hydrogen. New capabilities in metabolic engineering combined with intrinsic utilization of lignocellulosic materials position these organisms to provide a new paradigm for consolidated bioprocessing of fuels and other products from

  9. Evolutionarily engineered ethanologenic yeast detoxifies lignocellulosic biomass conversion inhibitors by reprogrammed pathways.

    PubMed

    Liu, Z Lewis; Ma, Menggen; Song, Mingzhou

    2009-09-01

    Lignocellulosic biomass conversion inhibitors, furfural and HMF, inhibit microbial growth and interfere with subsequent fermentation of ethanol, posing significant challenges for a sustainable cellulosic ethanol conversion industry. Numerous yeast genes were found to be associated with the inhibitor tolerance. However, limited knowledge is available about mechanisms of the tolerance and the detoxification of the biomass conversion inhibitors. Using a robust standard for absolute mRNA quantification assay and a recently developed tolerant ethanologenic yeast Saccharomyces cerevisiae NRRL Y-50049, we investigate pathway-based transcription profiles relevant to the yeast tolerance and the inhibitor detoxification. Under the synergistic inhibitory challenges by furfural and HMF, Y-50049 was able to withstand the inhibitor stress, in situ detoxify furfural and HMF, and produce ethanol, while its parental control Y-12632 failed to function till 65 h after incubation. The tolerant strain Y-50049 displayed enriched genetic background with significantly higher abundant of transcripts for at least 16 genes than a non-tolerant parental strain Y-12632. The enhanced expression of ZWF1 appeared to drive glucose metabolism in favor of pentose phosphate pathway over glycolysis at earlier steps of glucose metabolisms. Cofactor NAD(P)H generation steps were likely accelerated by enzymes encoded by ZWF1, GND1, GND2, TDH1, and ALD4. NAD(P)H-dependent aldehyde reductions including conversion of furfural and HMF, in return, provided sufficient NAD(P)(+) for NAD(P)H regeneration in the yeast detoxification pathways. Enriched genetic background and a well maintained redox balance through reprogrammed expression responses of Y-50049 were accountable for the acquired tolerance and detoxification of furfural to furan methanol and HMF to furan dimethanol. We present significant gene interactions and regulatory networks involved in NAD(P)H regenerations and functional aldehyde reductions under

  10. Metabolic engineering of Caldicellulosiruptor bescii yields increased hydrogen production from lignocellulosic biomass

    PubMed Central

    2013-01-01

    Background Members of the anaerobic thermophilic bacterial genus Caldicellulosiruptor are emerging candidates for consolidated bioprocessing (CBP) because they are capable of efficiently growing on biomass without conventional pretreatment. C. bescii produces primarily lactate, acetate and hydrogen as fermentation products, and while some Caldicellulosiruptor strains produce small amounts of ethanol C. bescii does not, making it an attractive background to examine the effects of metabolic engineering. The recent development of methods for genetic manipulation has set the stage for rational engineering of this genus for improved biofuel production. Here, we report the first targeted gene deletion, the gene encoding lactate dehydrogenase (ldh), for metabolic engineering of a member of this genus. Results A deletion of the C. bescii L-lactate dehydrogenase gene (ldh) was constructed on a non-replicating plasmid and introduced into the C. bescii chromosome by marker replacement. The resulting strain failed to produce detectable levels of lactate from cellobiose and maltose, instead increasing production of acetate and H2 by 21-34% relative to the wild type and ΔpyrFA parent strains. The same phenotype was observed on a real-world substrate – switchgrass (Panicum virgatum). Furthermore, the ldh deletion strain grew to a higher maximum optical density than the wild type on maltose and cellobiose, consistent with the prediction that the mutant would gain additional ATP with increased acetate production. Conclusions Deletion of ldh in C. bescii is the first use of recently developed genetic methods for metabolic engineering of these bacteria. This deletion resulted in a redirection of electron flow from production of lactate to acetate and hydrogen. New capabilities in metabolic engineering combined with intrinsic utilization of lignocellulosic materials position these organisms to provide a new paradigm for consolidated bioprocessing of fuels and other products from

  11. Evolutionarily engineered ethanologenic yeast detoxifies lignocellulosic biomass conversion inhibitors by reprogrammed pathways

    PubMed Central

    Ma, Menggen; Song, Mingzhou

    2010-01-01

    Lignocellulosic biomass conversion inhibitors, furfural and HMF, inhibit microbial growth and interfere with subsequent fermentation of ethanol, posing significant challenges for a sustainable cellulosic ethanol conversion industry. Numerous yeast genes were found to be associated with the inhibitor tolerance. However, limited knowledge is available about mechanisms of the tolerance and the detoxification of the biomass conversion inhibitors. Using a robust standard for absolute mRNA quantification assay and a recently developed tolerant ethanologenic yeast Saccharomyces cerevisiae NRRL Y-50049, we investigate pathway-based transcription profiles relevant to the yeast tolerance and the inhibitor detoxification. Under the synergistic inhibitory challenges by furfural and HMF, Y-50049 was able to withstand the inhibitor stress, in situ detoxify furfural and HMF, and produce ethanol, while its parental control Y-12632 failed to function till 65 h after incubation. The tolerant strain Y-50049 displayed enriched genetic background with significantly higher abundant of transcripts for at least 16 genes than a non-tolerant parental strain Y-12632. The enhanced expression of ZWF1 appeared to drive glucose metabolism in favor of pentose phosphate pathway over glycolysis at earlier steps of glucose metabolisms. Cofactor NAD(P)H generation steps were likely accelerated by enzymes encoded by ZWF1, GND1, GND2, TDH1, and ALD4. NAD(P)H-dependent aldehyde reductions including conversion of furfural and HMF, in return, provided sufficient NAD(P)+ for NAD(P)H regeneration in the yeast detoxification pathways. Enriched genetic background and a well maintained redox balance through reprogrammed expression responses of Y-50049 were accountable for the acquired tolerance and detoxification of furfural to furan methanol and HMF to furan dimethanol. We present significant gene interactions and regulatory networks involved in NAD(P)H regenerations and functional aldehyde reductions under

  12. Quantification of crystalline cellulose in lignocellulosic biomass using sum frequency generation (SFG) vibration spectroscopy and comparison with other analytical methods.

    PubMed

    Barnette, Anna L; Lee, Christopher; Bradley, Laura C; Schreiner, Edward P; Park, Yong Bum; Shin, Heenae; Cosgrove, Daniel J; Park, Sunkyu; Kim, Seong H

    2012-07-01

    The non-centrosymmetry requirement of sum frequency generation (SFG) vibration spectroscopy allows the detection and quantification of crystalline cellulose in lignocellulose biomass without spectral interferences from hemicelluloses and lignin. This paper shows a correlation between the amount of crystalline cellulose in biomass and the SFG signal intensity. Model biomass samples were prepared by mixing commercially available cellulose, xylan, and lignin to defined concentrations. The SFG signal intensity was found sensitive to a wide range of crystallinity, but varied non-linearly with the mass fraction of cellulose in the samples. This might be due to the matrix effects such as light scattering and absorption by xylan and lignin, as well as the non-linear density dependence of the SFG process itself. Comparison with other techniques such as XRD, FT-Raman, FT-IR and NMR demonstrate that SFG can be a complementary and sensitive tool to assess crystalline cellulose in biomass.

  13. Consequences of poly(vinyl chloride) presence on the thermochemical process of lignocellulosic biomass in CO₂ by thermogravimetric analysis.

    PubMed

    He, Yao; Ma, Xiaoqian; Zeng, Guangbo

    2015-02-01

    The thermochemical processes of lignocellulosic biomass and its mixtures with poly(vinyl chloride) (PVC) fractions were investigated by thermogravimetric analysis in CO2 atmosphere. Superposition property was assumed to examine whether and/or to what extent interactions occurred during the mixture decomposition. Results showed that interactions existed, of which the intensities changed with reaction stage, heating rate and PVC quantity, and they actively behaved toward the decomposition in most cases. With PVC presence, lignocellulosic biomass turned from three-stage to four-stage decomposition process where the reactions occurred at lower temperatures with heightened intensity, especially in the first stage. The measured activation energies calculated by Ozawa-Flynn-Wall and Vyazovkin methods were of minor difference <5 kJ/mol, and comparing them between materials in each stage confirmed the results of interaction impact. This work provides a theoretical basis bringing about the possibilities of recycling CO2 into a reaction medium of thermo-treatment of lignocellulosic material with PVC contaminants.

  14. SO2 -catalyzed steam explosion: the effects of different severity on digestibility, accessibility, and crystallinity of lignocellulosic biomass.

    PubMed

    Kang, Yuzhi; Bansal, Prabuddha; Realff, Matthew J; Bommarius, Andreas S

    2013-01-01

    Lignocellulosic biomass is the most promising feedstock for biofuels production. To enhance the efficiency of enzymatic hydrolysis, lignocellulosics needs to be pretreated to lower their recalcitrance. SO(2) -catalyzed steam explosion is an efficient and relatively cost-efficient pretreatment method for softwood. This work investigates the effects of steam explosion severity on the digestibility, accessibility, and crystallinity of Loblolly pine. Higher severity was found to increase the accessibility of the feedstock while also promoting nonselective degradation of carbohydrates. The adsorption behavior of Celluclast® enzymes on steam-exploded Loblolly pine (SELP) can be described by a Langmuir isotherm. Cellulose crystallinity was found to first increase and then decrease with increasing pretreatment severity. A linear relationship between initial hydrolysis rates and crystallinity index (CrI) of pretreated Loblolly pine was found; moreover, a strong correlation between X-ray diffraction intensities and initial rates was confirmed. The findings demonstrate the significance of CrI in enzymatic hydrolysis of pretreated lignocellulosic biomass.

  15. Differences in the adsorption of enzymes onto lignins from diverse types of lignocellulosic biomass and the underlying mechanism.

    PubMed

    Guo, Fenfen; Shi, Wenjing; Sun, Wan; Li, Xuezhi; Wang, Feifei; Zhao, Jian; Qu, Yinbo

    2014-03-14

    Non-productive cellulase adsorption onto lignin has always been deemed to negatively affect the enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding enzyme-lignin interactions is essential for the development of enzyme mixtures, the processes of lignocellulose hydrolysis, and the genetic modification of lignocellulosic biomass and enzymes. In this work, we examined the properties of six lignins from diverse types of lignocellulosic biomass (aspen, pine, corn stover, kenaf, and two Arabidopsis lines, wild-type and SALK mutant of fah1) to determine the mechanism of differences in their adsorption of enzymes. We found that lignin sources affected enzyme adsorption using structural features, such as functional groups and lignin composition. Guaiacyl (G) lignin had a higher adsorption capacity on enzymes than syringyl (S) lignin. The low S/G ratio and high uniform lignin fragment size had good correlations with high adsorption capacity. A higher content of phenolic hydroxyl groups and a lower content of carboxylic acid groups resulted in stronger adsorption affinity for corn stover lignin (CL) than for kenaf lignin (KL) and aspen lignin (AL). The lower amount of aliphatic hydroxyls that reduced hydrophobic interactions could explain the higher adsorption capacity of pine lignin (PL) than CL. Enzyme activity assays, as well as the hydrolysis of Avicel, phosphoric acid-swollen cellulose (PASC), and holocellulose, were performed to study the behaviors of mono-component enzymes that resulted in adsorption. We found that cellobiohydrolase (CBH) and xylanase were adsorbed the most by all lignins, endoglucanase (EG) showed less inhibition, and β-glucosidase (BG) was the least affected by lignins, indicating the important role of carbohydrate-binding module (CBM) in protein adsorption. Lignin sources affect enzyme adsorption using structural features and lignin composition, such as S/G ratio, carboxylic acid, aliphatic hydroxyl, and phenolic hydroxyl

  16. Expression of Trichoderma reesei β-mannanase in tobacco chloroplasts and its utilization in lignocellulosic woody biomass hydrolysis.

    PubMed

    Agrawal, Pankaj; Verma, Dheeraj; Daniell, Henry

    2011-01-01

    Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plant-based production of these enzymes on large scale offers a cost-effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. β-mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, the man1 gene encoding β-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed site-specific transgene integration into the tobacco chloroplast genomes and homoplasmy. Transplastomic plants were fertile and set viable seeds. Germination of seeds in the selection medium showed inheritance of transgenes into the progeny without any Mendelian segregation. Expression of endo-β-mannanase for the first time in plants facilitated its characterization for use in enhanced lignocellulosic biomass hydrolysis. Gel diffusion assay for endo-β-mannanase showed the zone of clearance confirming functionality of chloroplast-derived mannanase. Endo-β-mannanase expression levels reached up to 25 units per gram of leaf (fresh weight). Chloroplast-derived mannanase had higher temperature stability (40 °C to 70 °C) and wider pH optima (pH 3.0 to 7.0) than E.coli enzyme extracts. Plant crude extracts showed 6-7 fold higher enzyme activity than E.coli extracts due to the formation of disulfide bonds in chloroplasts, thereby facilitating their direct utilization in enzyme cocktails without any purification. Chloroplast-derived mannanase when added to the enzyme cocktail containing a combination of different plant-derived enzymes yielded 20% more glucose equivalents from pinewood than the cocktail without

  17. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

    SciTech Connect

    Joyce, Blake L.; Zheljazkov, Valtcho D.; Sykes, Robert; Cantrell, Charles L.; Hamilton, Choo; Mann, David G. J.; Rodriguez, Miguel; Mielenz, Jonathan R.; Astatkie, Tess; C. Neal Stewart Jr.

    2015-10-05

    Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749–3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass) -1 and pretreated palmarosa yielded 170 mL ethanol (g biomass) -1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

  18. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

    DOE PAGES

    Joyce, Blake L.; Zheljazkov, Valtcho D.; Sykes, Robert; ...

    2015-10-05

    Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749–3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanolmore » (g biomass) -1 and pretreated palmarosa yielded 170 mL ethanol (g biomass) -1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.« less

  19. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii.

    PubMed

    Joyce, Blake L; Zheljazkov, Valtcho D; Sykes, Robert; Cantrell, Charles L; Hamilton, Choo; Mann, David G J; Rodriguez, Miguel; Mielenz, Jonathan R; Astatkie, Tess; Stewart, C Neal

    2015-01-01

    Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

  20. Comparative study on pyrolysis of lignocellulosic and algal biomass using a thermogravimetric and a fixed-bed reactor.

    PubMed

    Yuan, Ting; Tahmasebi, Arash; Yu, Jianglong

    2015-01-01

    Pyrolysis characteristics of four algal and lignocellulosic biomass samples were studied by using a thermogravimetric analyzer (TGA) and a fixed-bed reactor. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. The average activation energy for pyrolysis of biomass samples by FWO and KAS methods in this study were in the range of 211.09-291.19kJ/mol. CO2 was the main gas component in the early stage of pyrolysis, whereas H2 and CH4 concentrations increased with increasing pyrolysis temperature. Bio-oil from Chlorellavulgaris showed higher content of nitrogen containing compounds compared to lignocellulosic biomass. The concentration of aromatic organic compounds such as phenol and its derivatives were increased with increasing pyrolysis temperature up to 700°C. FTIR analysis results showed that with increasing pyrolysis temperature, the concentration of OH, CH, CO, OCH3, and CO functional groups in char decreased sharply. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

    PubMed Central

    Joyce, Blake L.; Zheljazkov, Valtcho D.; Sykes, Robert; Cantrell, Charles L.; Hamilton, Choo; Mann, David G. J.; Rodriguez, Miguel; Mielenz, Jonathan R.; Astatkie, Tess; Stewart, C. Neal

    2015-01-01

    Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749–3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels. PMID:26437026

  2. The use of thermostable bacterial hemicellulases improves the conversion of lignocellulosic biomass to valuable molecules.

    PubMed

    Rakotoarivonina, Harivony; Revol, Pierre-Vincent; Aubry, Nathalie; Rémond, Caroline

    2016-09-01

    The hydrolysis of xylans, one of the main classes of carbohydrates that constitute lignocellulosic biomass, requires the synergistic action of several enzymes. The development of efficient enzymatic strategies for hydrolysis remains a challenge in the pursuit of viable biorefineries, particularly with respect to the valorisation of pentoses. The approach developed in this work is based on obtaining and characterising hemicellulasic cocktails from Thermobacillus xylanilyticus after culturing this bacterium on the hemicellulose-rich substrates wheat bran and wheat straw, which differ in their chemistries. The two obtained cocktails (WSC and WBC, for cocktails obtained from wheat straw and wheat bran, respectively) were resistant to a broad range of temperature and pH conditions. At 60 °C, both cocktails efficiently liberated pentoses and phenolic acids from wheat bran (liberating more than 60, 30 and 40 % of the total xylose, arabinose and ferulic acid in wheat bran, respectively). They acted to a lesser extent on the more recalcitrant wheat straw, with hydrolytic yields of more than 30 % of the total arabinose and xylose content and 22 % of the ferulic acid content. Hydrolysis is associated with a high rate of sugar monomerisation. When associated with cellulases, high quantities of glucose were also obtained. On wheat bran, total glucose yields were improved by 70 % compared to the action of cellulases alone. This improvement was obtained by cellulase complementation either with WSC or with WBC. On wheat straw, similar levels of total glucose were obtained for cellulases alone or complemented with WSC or WBC. Interestingly, the complementation of cellulases with WSC or WBC induced an increase in the monomeric glucose yield of more than 20 % compared to cellulases alone.

  3. Linking pyrolysis and anaerobic digestion (Py-AD) for the conversion of lignocellulosic biomass.

    PubMed

    Fabbri, Daniele; Torri, Cristian

    2016-04-01

    Biogas is a mixture of CO2 and CH4 produced by a consortia of Bacteria and Archeae operating in anaerobic digestion (AD) plants. Biogas can be burnt as such in engines to produce electricity and heat or upgraded into biomethane. Biomethane is a drop-in fuel that can be injected in the natural gas grid or utilised as a transport fuel. While a wide array of biomass feedstock can be degraded into biogas, unconverted lignin, hemicellulose and cellulose end up in the co-product digestate leaving a large portion of chemical energy unutilised. Pyrolysis (Py) transforms in a single step and without chemical reagents the lignocellulose matrix into gaseous (syngas), liquid (bio-oil, pyrolysis oil) and solid (biochar) fractions for the development of renewable fuels and materials. The Py route applied downstream to AD is actively investigated in order to valorise the solid digestate presently destined only for soil applications. Coupling Py upstream to AD is an emerging field of research aimed at expanding the feedstock towards biologically recalcitrant substrates (wood, paper, sludge). The biomethanation potential was demonstrated for gaseous (H2/CO) and water soluble pyrolysis products, while the influence of insoluble pyrolytic lignin remains fairly unexplored. Biochar can promote the production of biomethane by acting as a support for microorganism colonisation, conductor for direct interspecies electron transfer, sorbent for hydrophobic inhibitors, and reactant for in situ biogas upgrading. Enhancing the advantages (carbon source) over the side effects (toxicity) of Py fractions represents the main challenge of Py-AD. This can be addressed by increasing the selectivity of the thermochemical process or improving the ecological flexibility of mixed bacterial consortia towards chemically complex environments.

  4. Comparative study on two-step concentrated acid hydrolysis for the extraction of sugars from lignocellulosic biomass.

    PubMed

    Wijaya, Yanuar Philip; Putra, Robertus Dhimas Dhewangga; Widyaya, Vania Tanda; Ha, Jeong-Myeong; Suh, Dong Jin; Kim, Chang Soo

    2014-07-01

    Among all the feasible thermochemical conversion processes, concentrated acid hydrolysis has been applied to break the crystalline structure of cellulose efficiently and scale up for mass production as lignocellulosic biomass fractionation process. Process conditions are optimized by investigating the effect of decrystallization sulfuric acid concentration (65-80 wt%), hydrolysis temperature (80°C and 100°C), hydrolysis reaction time (during two hours), and biomass species (oak wood, pine wood, and empty fruit bunch (EFB) of palm oil) toward sugar recovery. At the optimum process condition, 78-96% sugars out of theoretically extractable sugars have been fractionated by concentrated sulfuric acid hydrolysis of the three different biomass species with 87-90 g/L sugar concentration in the hydrolyzate and highest recalcitrance of pine (softwood) was determined by the correlation of crystallinity index and sugar yield considering reaction severity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Comparative study on pyrolysis of lignocellulosic and algal biomass using pyrolysis-gas chromatography/mass spectrometry.

    PubMed

    Li, Kai; Zhang, Liqiang; Zhu, Liang; Zhu, Xifeng

    2017-06-01

    The cornstalk and chlorella were selected as the representative of lignocelulosic and algal biomass, and the pyrolysis experiments of them were carried out using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The physicochemical properties of samples and the pyrolytic product distribution were presented. And then the compositional differences between the two kinds of pyrolytic products were studied, the relevant pyrolysis mechanisms were analyzed systematically. Pyrolytic vapor from lignocellulosic biomass contained more phenolic and carbonyl compounds while that from algal biomass contained more long-chain fatty acids, nitrogen-containing compounds and fewer carbonyl compounds. Maillard reaction is conducive to the conversion of carbonyl compounds to nitrogenous heterocyclic compounds with better thermal stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Activation of lignocellulosic biomass for higher sugar yields using aqueous ionic liquid at low severity process conditions.

    PubMed

    Parthasarathi, Ramakrishnan; Sun, Jian; Dutta, Tanmoy; Sun, Ning; Pattathil, Sivakumar; Murthy Konda, N V S N; Peralta, Angelo Gabriel; Simmons, Blake A; Singh, Seema

    2016-01-01

    Concerns around greenhouse gas emissions necessitate the development of sustainable processes for the production of chemicals, materials, and fuels from alternative renewable sources. The lignocellulosic plant cell walls are one of the most abundant sources of carbon for renewable bioenergy production. Certain ionic liquids (ILs) are very effective at disrupting the plant cell walls of lignocellulose, and generate a substrate that is effectively hydrolyzed into fermentable sugars. Conventional ILs are relatively expensive in terms of purchase price, and the most effective imidazolium-based ILs also require energy intensive processing conditions (>140 °C, 3 h) to release >90 % fermentable sugar yields after saccharification. We have developed a highly effective pretreatment technology utilizing the relatively inexpensive IL comprised tetrabutylammonium [TBA](+) and hydroxide [OH](-) ions that generate high glucose yields (~95 %) after pretreatment at very mild processing conditions (50 °C). The efficiency of [TBA][OH] pretreatment of lignocellulose was further studied by analyzing chemical composition, powder X-ray diffraction for cellulose structure, NMR and SEC for lignin dissolution/depolymerization, and glycome profiling for cell wall modifications. Glycome profiling experiments and computational results indicate that removal of the noncellulosic polysaccharides occurs due to the ionic mobility of [TBA][OH] and is the key factor in determining pretreatment efficiency. Process modeling and energy demand analysis suggests that this [TBA][OH] pretreatment could potentially reduce the energy required in the pretreatment unit operation by more than 75 %. By leveraging the benefits of ILs that are effective at very mild processing conditions, such as [TBA][OH], lignocellulosic biomass can be pretreated at similar efficiency as top performing conventional ILs, such as 1-ethyl-3-methylimidazolium acetate [C2C1Im][OAc], but at much lower temperatures, and with

  7. Lignocellulosic crop supply chains (eg, Miscanthus, switchgrass, reed canary grass, rye, giant reed, etc.) Chapter 12 of "Biomass Supply Chains for Bioenergy and Biorefining"

    SciTech Connect

    Roni, Mohammad S.; Cafferty, Kara G.; Hess, J. Richard; Jacobson, Jacob J.; Kenney, Kevin L.; Searcy, Erin; Tumuluru, Jaya S.

    2016-03-01

    This chapter provides an overview of lignocellulosic crop supply chains such as Miscanthus, switch grass, reed canary grass, rye, and giant reed by outlining typical logistic operations in support of a liquid biofuel market. We present two strategies for managing feedstocks within the biomass supply system: (1) the conventional bale feedstock supply system and (2) the advanced supply system concept. Finally, we discuss feedstock blending and integrated landscape management as innovative improvements to the lignocellulosic crop supply chain.

  8. Development of a system for characterizing biomass quality of lignocellulosic feedstocks for biochemical conversion

    NASA Astrophysics Data System (ADS)

    Murphy, Patrick Thomas

    The purpose of this research was twofold: (i) to develop a system for screening lignocellulosic biomass feedstocks for biochemical conversion to biofuels and (ii) to evaluate brown midrib corn stover as feedstock for ethanol production. In the first study (Chapter 2), we investigated the potential of corn stover from bm1-4 hybrids for increased ethanol production and reduced pretreatment intensity compared to corn stover from the isogenic normal hybrid. Corn stover from hybrid W64A X A619 and respective isogenic bm hybrids was pretreated by aqueous ammonia steeping using ammonium hydroxide concentrations from 0 to 30%, by weight, and the resulting residues underwent simultaneous saccharification and cofermentation (SSCF) to ethanol. Dry matter (DM) digested by SSCF increased with increasing ammonium hydroxide concentration across all genotypes (P>0.0001) from 277 g kg-1 DM in the control to 439 g kg-1 DM in the 30% ammonium hydroxide pretreatment. The bm corn stover materials averaged 373 g kg-1 DM of DM digested by SSCF compared with 335 g kg-1 DM for the normal corn stover (P<0.0001). Of the bm mutations, bm3 had (i) the greatest effect on cell-wall carbohydrate hydrolysis of corn stover, (ii) the lowest initial cell-wall carbohydrate concentration, (iii) the lowest dry matter remaining after pretreatment, and (iv) the highest amount of monosaccharides released during enzymatic hydrolysis. However, bm corn stover did not reduce the severity of aqueous ammonia steeping pretreatment needed to maximize DM hydrolysis during SSCF compared with normal corn stover. In the remaining studies (Chapters 3 thru 5), a system for analyzing the quality of lignocellulosic biomass feedstocks for biochemical conversion to biofuels (i.e., pretreatment, enzymatic hydrolysis, and fermentation) was developed. To accomplish this, a carbohydrate availability model was developed to characterize feedstock quality. The model partitions carbohydrates within a feedstock material into

  9. Pretreatment of lignocellulosic biomass with renewable cholinium ionic liquids: Biomass fractionation, enzymatic digestion and ionic liquid reuse.

    PubMed

    An, Yan-Xia; Zong, Min-Hua; Wu, Hong; Li, Ning

    2015-09-01

    Pretreatment of lignocelluloses is a key step in the biorefinery for production of biofuels and valuable platform chemicals. In this work, various lignocelluloses were pretreated using cholinium ionic liquids (ILs) that are wholly composed of biomaterials, and fractionated into carbohydrate-rich materials (CRMs) and lignin-rich materials (LRMs). Cholinium ILs were found to be effective pretreatment solvents for grass lignocelluloses as well as eucalyptus, resulting in significant improvements in the glucose yields (58-75%) in subsequent enzymatic hydrolysis, while they were inefficient to make pine susceptible to biodegradation. Approximately 46% of lignin in native rice straw was fractionated as LRM after pretreatment using cholinium argininate ([Ch][Arg]). [Ch][Arg] showed excellent recyclability, and the total recovery was as high as 75% after reused for 8 cycles. Besides, rice straw pretreated by the recycled IL remained highly digestible, and good glucose yields (63-75%) were achieved after its enzymatic hydrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Efficient Degradation of Lignocellulosic Plant Biomass, without Pretreatment, by the Thermophilic Anaerobe “Anaerocellum thermophilum” DSM 6725▿

    PubMed Central

    Yang, Sung-Jae; Kataeva, Irina; Hamilton-Brehm, Scott D.; Engle, Nancy L.; Tschaplinski, Timothy J.; Doeppke, Crissa; Davis, Mark; Westpheling, Janet; Adams, Michael W. W.

    2009-01-01

    Very few cultivated microorganisms can degrade lignocellulosic biomass without chemical pretreatment. We show here that “Anaerocellum thermophilum” DSM 6725, an anaerobic bacterium that grows optimally at 75°C, efficiently utilizes various types of untreated plant biomass, as well as crystalline cellulose and xylan. These include hardwoods such as poplar, low-lignin grasses such as napier and Bermuda grasses, and high-lignin grasses such as switchgrass. The organism did not utilize only the soluble fraction of the untreated biomass, since insoluble plant biomass (as well as cellulose and xylan) obtained after washing at 75°C for 18 h also served as a growth substrate. The predominant end products from all growth substrates were hydrogen, acetate, and lactate. Glucose and cellobiose (on crystalline cellulose) and xylose and xylobiose (on xylan) also accumulated in the growth media during growth on the defined substrates but not during growth on the plant biomass. A. thermophilum DSM 6725 grew well on first- and second-spent biomass derived from poplar and switchgrass, where spent biomass is defined as the insoluble growth substrate recovered after the organism has reached late stationary phase. No evidence was found for the direct attachment of A. thermophilum DSM 6725 to the plant biomass. This organism differs from the closely related strain A. thermophilum Z-1320 in its ability to grow on xylose and pectin. Caldicellulosiruptor saccharolyticus DSM 8903 (optimum growth temperature, 70°C), a close relative of A. thermophilum DSM 6725, grew well on switchgrass but not on poplar, indicating a significant difference in the biomass-degrading abilities of these two otherwise very similar organisms. PMID:19465524

  11. Advances in catalytic production of bio-based polyester monomer 2,5-furandicarboxylic acid derived from lignocellulosic biomass.

    PubMed

    Zhang, Junhua; Li, Junke; Tang, Yanjun; Lin, Lu; Long, Minnan

    2015-10-05

    Recently, the production and utilization of 2,5-furandicarboxylic acid (FDCA) have become a hot research topic in catalyst field and polyester industry for its special chemical structure and a wide range of raw material source. FDCA is a potential replacement for the terephthalic acid monomer used in the production of poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), which opens up a new pathway for obtaining biomass-based polyester to replace or partially replace petroleum based polyester. Here, we mainly reviewed the catalytic pathway for the synthesis of FDCA derived from lignocellulosic biomass or from the related downstream products, such as glucose, 5-hydroxymethylfurfural (HMF). Moreover, the utilization of oxidation catalysts, the reaction mechanism, the existing limitations and unsolved challenges were also elaborated in detail. Therefore, we hope this mini review provides a helpful overview and insight to readers in this exciting research area.

  12. Multifaceted metabolomics approaches for characterization of lignocellulosic biomass degradation products formed during ammonia fiber expansion pretreatment

    NASA Astrophysics Data System (ADS)

    Vismeh, Ramin

    Lignocellulosic biomass represents a rather unused resource for production of biofuels, and it offers an alternative to food sources including corn starch. However, structural and compositional impediments limit the digestibility of sugar polymers in biomass cell walls. Thermochemical pretreatments improve accessibility of cellulose and hemicellulose to hydrolytic enzymes. However, most pretreatment methods generate compounds that either inhibit enzymatic hydrolysis or exhibit toxicity to fermentive microorganisms. Characterization and quantification of these products are essential for understanding chemistry of the pretreatment and optimizing the process efficiency to achieve higher ethanol yields. Identification of oligosaccharides released during pretreatment is also critical for choosing hydrolases necessary for cost-effective hydrolysis of cellulose and hemicellulose to fermentable monomeric sugars. Two chapters in this dissertation describe new mass spectrometry-based strategies for characterization and quantification of products that are formed during ammonia fiber expansion (AFEX) pretreatment of corn stover. Comparison of Liquid Chromatography Mass Spectrometry (LC/MS) profiles of AFEX-treated corn stover (AFEXTCS) and untreated corn stover (UTCS) extract shows that ammonolysis of lignin carbohydrate ester linkages generates a suite of nitrogenous compounds that are present only in the AFEXTCS extract and represent a loss of ammonia during processing. Several of these products including acetamide, feruloyl, coumaroyl and diferuloyl amides were characterized and quantified in the AFEXTCS extracts. The total amount of characterized and uncharacterized phenolic amides measured 17.4 mg/g AFEXTCS. Maillard reaction products including pyrazines and imidazoles were also identified and measured in the AFEXTCS extract totaling almost 1 mg/g AFEXTCS. The total of quantified nitrogenous products that are formed during AFEX was 43.4 mg/g AFEXTCS which was equivalent

  13. Microbial surface displayed enzymes based biofuel cell utilizing degradation products of lignocellulosic biomass for direct electrical energy.

    PubMed

    Fan, Shuqin; Hou, Chuantao; Liang, Bo; Feng, Ruirui; Liu, Aihua

    2015-09-01

    In this work, a bacterial surface displaying enzyme based two-compartment biofuel cell for the direct electrical energy conversion from degradation products of lignocellulosic biomass is reported. Considering that the main degradation products of the lignocellulose are glucose and xylose, xylose dehydrogenase (XDH) displayed bacteria (XDH-bacteria) and glucose dehydrogenase (GDH) displayed bacteria (GDH-bacteria) were used as anode catalysts in anode chamber with methylene blue as electron transfer mediator. While the cathode chamber was constructed with laccase/multi-walled-carbon nanotube/glassy-carbon-electrode. XDH-bacteria exhibited 1.75 times higher catalytic efficiency than GDH-bacteria. This assembled enzymatic fuel cell exhibited a high open-circuit potential of 0.80 V, acceptable stability and energy conversion efficiency. Moreover, the maximum power density of the cell could reach 53 μW cm(-2) when fueled with degradation products of corn stalk. Thus, this finding holds great potential to directly convert degradation products of biomass into electrical energy.

  14. Unravelling the Interactions between Hydrolytic and Oxidative Enzymes in Degradation of Lignocellulosic Biomass by Sporothrix carnis under Various Fermentation Conditions

    PubMed Central

    Ogunyewo, Olusola A.; Olajuyigbe, Folasade M.

    2016-01-01

    The mechanism underlying the action of lignocellulolytic enzymes in biodegradation of lignocellulosic biomass remains unclear; hence, it is crucial to investigate enzymatic interactions involved in the process. In this study, degradation of corn cob by Sporothrix carnis and involvement of lignocellulolytic enzymes in biodegradation were investigated over 240 h cultivation period. About 60% degradation of corn cob was achieved by S. carnis at the end of fermentation. The yields of hydrolytic enzymes, cellulase and xylanase, were higher than oxidative enzymes, laccase and peroxidase, over 144 h fermentation period. Maximum yields of cellulase (854.4 U/mg) and xylanase (789.6 U/mg) were at 96 and 144 h, respectively. Laccase and peroxidase were produced cooperatively with maximum yields of 489.06 U/mg and 585.39 U/mg at 144 h. Drastic decline in production of cellulase at 144 h (242.01 U/mg) and xylanase at 192 h (192.2 U/mg) indicates that they play initial roles in biodegradation of lignocellulosic biomass while laccase and peroxidase play later roles. Optimal degradation of corn cob (76.6%) and production of hydrolytic and oxidative enzymes were achieved with 2.5% inoculum at pH 6.0. Results suggest synergy in interactions between the hydrolytic and oxidative enzymes which can be optimized for improved biodegradation. PMID:26881077

  15. Network-based integration of systems genetics data reveals pathways associated with lignocellulosic biomass accumulation and processing

    DOE PAGES

    Mizrachi, Eshchar; Verbeke, Lieven; Christie, Nanette; ...

    2017-01-17

    As a consequence of their remarkable adaptability, fast growth, and superior wood properties, eucalypt tree plantations have emerged as key renewable feedstocks (over 20 million ha globally) for the production of pulp, paper, bioenergy, and other lignocellulosic products. However, most biomass properties such as growth, wood density, and wood chemistry are complex traits that are hard to improve in long-lived perennials. Systems genetics, a process of harnessing multiple levels of component trait information (e.g., transcript, protein, and metabolite variation) in populations that vary in complex traits, has proven effective for dissecting the genetics and biology of such traits. We havemore » applied a network-based data integration (NBDI) method for a systems-level analysis of genes, processes and pathways underlying biomass and bioenergy-related traits using a segregating Eucalyptus hybrid population. We show that the integrative approach can link biologically meaningful sets of genes to complex traits and at the same time reveal the molecular basis of trait variation. Gene sets identified for related woody biomass traits were found to share regulatory loci, cluster in network neighborhoods, and exhibit enrichment for molecular functions such as xylan metabolism and cell wall development. These findings offer a framework for identifying the molecular underpinnings of complex biomass and bioprocessing-related traits. Furthermore, a more thorough understanding of the molecular basis of plant biomass traits should provide additional opportunities for the establishment of a sustainable bio-based economy.« less

  16. Network-based integration of systems genetics data reveals pathways associated with lignocellulosic biomass accumulation and processing

    PubMed Central

    Mizrachi, Eshchar; Christie, Nanette; Fierro, Ana C.; Mansfield, Shawn D.; Davis, Mark F.; Gjersing, Erica; Tuskan, Gerald A.; Van Montagu, Marc; Van de Peer, Yves; Marchal, Kathleen; Myburg, Alexander A.

    2017-01-01

    As a consequence of their remarkable adaptability, fast growth, and superior wood properties, eucalypt tree plantations have emerged as key renewable feedstocks (over 20 million ha globally) for the production of pulp, paper, bioenergy, and other lignocellulosic products. However, most biomass properties such as growth, wood density, and wood chemistry are complex traits that are hard to improve in long-lived perennials. Systems genetics, a process of harnessing multiple levels of component trait information (e.g., transcript, protein, and metabolite variation) in populations that vary in complex traits, has proven effective for dissecting the genetics and biology of such traits. We have applied a network-based data integration (NBDI) method for a systems-level analysis of genes, processes and pathways underlying biomass and bioenergy-related traits using a segregating Eucalyptus hybrid population. We show that the integrative approach can link biologically meaningful sets of genes to complex traits and at the same time reveal the molecular basis of trait variation. Gene sets identified for related woody biomass traits were found to share regulatory loci, cluster in network neighborhoods, and exhibit enrichment for molecular functions such as xylan metabolism and cell wall development. These findings offer a framework for identifying the molecular underpinnings of complex biomass and bioprocessing-related traits. A more thorough understanding of the molecular basis of plant biomass traits should provide additional opportunities for the establishment of a sustainable bio-based economy. PMID:28096391

  17. Network-based integration of systems genetics data reveals pathways associated with lignocellulosic biomass accumulation and processing.

    PubMed

    Mizrachi, Eshchar; Verbeke, Lieven; Christie, Nanette; Fierro, Ana C; Mansfield, Shawn D; Davis, Mark F; Gjersing, Erica; Tuskan, Gerald A; Van Montagu, Marc; Van de Peer, Yves; Marchal, Kathleen; Myburg, Alexander A

    2017-01-31

    As a consequence of their remarkable adaptability, fast growth, and superior wood properties, eucalypt tree plantations have emerged as key renewable feedstocks (over 20 million ha globally) for the production of pulp, paper, bioenergy, and other lignocellulosic products. However, most biomass properties such as growth, wood density, and wood chemistry are complex traits that are hard to improve in long-lived perennials. Systems genetics, a process of harnessing multiple levels of component trait information (e.g., transcript, protein, and metabolite variation) in populations that vary in complex traits, has proven effective for dissecting the genetics and biology of such traits. We have applied a network-based data integration (NBDI) method for a systems-level analysis of genes, processes and pathways underlying biomass and bioenergy-related traits using a segregating Eucalyptus hybrid population. We show that the integrative approach can link biologically meaningful sets of genes to complex traits and at the same time reveal the molecular basis of trait variation. Gene sets identified for related woody biomass traits were found to share regulatory loci, cluster in network neighborhoods, and exhibit enrichment for molecular functions such as xylan metabolism and cell wall development. These findings offer a framework for identifying the molecular underpinnings of complex biomass and bioprocessing-related traits. A more thorough understanding of the molecular basis of plant biomass traits should provide additional opportunities for the establishment of a sustainable bio-based economy.

  18. Techno-economic Analysis for the Conversion of Lignocellulosic Biomass to Gasoline via the Methanol-to-Gasoline (MTG) Process

    SciTech Connect

    Jones, Susanne B.; Zhu, Yunhua

    2009-05-01

    Biomass is a renewable energy resource that can be converted into liquid fuel suitable for transportation applications. As a widely available biomass form, lignocellulosic biomass can have a major impact on domestic transportation fuel supplies and thus help meet the Energy Independence and Security Act renewable energy goals (U.S. Congress 2007). With gasification technology, biomass can be converted to gasoline via methanol synthesis and methanol-to-gasoline (MTG) technologies. Producing a gasoline product that is infrastructure ready has much potential. Although the MTG technology has been commercially demonstrated with natural gas conversion, combining MTG with biomass gasification has not been shown. Therefore, a techno-economic evaluation for a biomass MTG process based on currently available technology was developed to provide information about benefits and risks of this technology. The economic assumptions used in this report are consistent with previous U.S. Department of Energy Office of Biomass Programs techno-economic assessments. The feedstock is assumed to be wood chips at 2000 metric ton/day (dry basis). Two kinds of gasification technologies were evaluated: an indirectly-heated gasifier and a directly-heated oxygen-blown gasifier. The gasoline selling prices (2008 USD) excluding taxes were estimated to be $3.20/gallon and $3.68/gallon for indirectly-heated gasified and directly-heated. This suggests that a process based on existing technology is economic only when crude prices are above $100/bbl. However, improvements in syngas cleanup combined with consolidated gasoline synthesis can potentially reduce the capital cost. In addition, improved synthesis catalysts and reactor design may allow increased yield.

  19. Two-step sequential liquefaction of lignocellulosic biomass by crude glycerol for the production of polyols and polyurethane foams.

    PubMed

    Hu, Shengjun; Li, Yebo

    2014-06-01

    A two-step sequential biomass liquefaction process was developed to produce bio-based polyols and polyurethane (PU) foams using crude glycerol as a liquefaction solvent. The first step, acid-catalyzed liquefaction, was highly effective in liquefying biomass, while the second step, base-catalyzed liquefaction, featured extensive condensation reactions. By using the developed two-step liquefaction process, the polyols produced from lignocellulosic biomass and crude glycerol containing 26-40% organic impurities showed hydroxyl numbers ranging from 536 to 936mgKOH/g, viscosities from 20.6 to 28.0Pas, and molecular weights (Mw) from 444 to 769g/mol. The PU foams produced had densities ranging from 0.04 to 0.05g/cm(3), compressive strengths from 223 to 420kPa, and thermal conductivities from 32.2 to 38.9mW/mK. Polyols and PU foams produced from the two-step liquefaction process had improved properties over their analogs derived from a one-step biomass liquefaction by crude glycerol process catalyzed by acid or base.

  20. Flocculating Zymomonas mobilis is a promising host to be engineered for fuel ethanol production from lignocellulosic biomass.

    PubMed

    Zhao, Ning; Bai, Yun; Liu, Chen-Guang; Zhao, Xin-Qing; Xu, Jian-Feng; Bai, Feng-Wu

    2014-03-01

    Whereas Saccharomyces cerevisiae uses the Embden-Meyerhof-Parnas pathway to metabolize glucose, Zymomonas mobilis uses the Entner-Doudoroff (ED) pathway. Employing the ED pathway, 50% less ATP is produced, which could lead to less biomass being accumulated during fermentation and an improved yield of ethanol. Moreover, Z. mobilis cells, which have a high specific surface area, consume glucose faster than S. cerevisiae, which could improve ethanol productivity. We performed ethanol fermentations using these two species under comparable conditions to validate these speculations. Increases of 3.5 and 3.3% in ethanol yield, and 58.1 and 77.8% in ethanol productivity, were observed in ethanol fermentations using Z. mobilis ZM4 in media containing ∼100 and 200 g/L glucose, respectively. Furthermore, ethanol fermentation bythe flocculating Z. mobilis ZM401 was explored. Although no significant difference was observed in ethanol yield and productivity, the flocculation of the bacterial species enabled biomass recovery by cost-effective sedimentation, instead of centrifugation with intensive capital investment and energy consumption. In addition, tolerance to inhibitory byproducts released during biomass pretreatment, particularly acetic acid and vanillin, was improved. These experimental results indicate that Z. mobilis, particularly its flocculating strain, is superior to S. cerevisiae as a host to be engineered for fuel ethanol production from lignocellulosic biomass.

  1. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Catalytic Conversion of Sugars to Hydrocarbons

    SciTech Connect

    Davis, R.; Tao, L.; Scarlata, C.; Tan, E. C. D.; Ross, J.; Lukas, J.; Sexton, D.

    2015-03-01

    This report describes one potential conversion process to hydrocarbon products by way of catalytic conversion of lignocellulosic-derived hydrolysate. This model leverages expertise established over time in biomass deconstruction and process integration research at NREL, while adding in new technology areas for sugar purification and catalysis. The overarching process design converts biomass to die die diesel- and naphtha-range fuels using dilute-acid pretreatment, enzymatic saccharification, purifications, and catalytic conversion focused on deoxygenating and oligomerizing biomass hydrolysates.

  2. Do furanic and phenolic compounds of lignocellulosic and algae biomass hydrolyzate inhibit anaerobic mixed cultures? A comprehensive review.

    PubMed

    Monlau, F; Sambusiti, C; Barakat, A; Quéméneur, M; Trably, E; Steyer, J-P; Carrère, H

    2014-01-01

    Nowadays there is a growing interest on the use of both lignocellulosic and algae biomass to produce biofuels (i.e. biohydrogen, ethanol and methane), as future alternatives to fossil fuels. In this purpose, thermal and thermo-chemical pretreatments have been widely investigated to overcome the natural physico-chemical barriers of such biomass and to enhance biofuel production from lignocellulosic residues and, more recently, marine biomass (i.e. macro and microalgae). However, the pretreatment technologies lead not only to the conversion of carbohydrate polymers (ie cellulose, hemicelluloses, starch, agar) to soluble monomeric sugar (ie glucose, xylose, arabinose, galactose), but also the generation of various by-products (i.e. furfural and 5-HMF). In the case of lignocellulosic residues, part of the lignin can also be degraded in lignin derived by-products, mainly composed of phenolic compounds. Although the negative impact of such by-products on ethanol production has been widely described in literature, studies on their impact on biohydrogen and methane production operated with mixed cultures are still very limited. This review aims to summarise and discuss literature data on the impact of pre-treatment by-products on H2-producing dark fermentation and anaerobic digestion processes when using mixed cultures as inoculum. As a summary, furanic (5-HMF, furfural) and phenolic compounds were found to be stronger inhibitors of the microbial dark fermentation than the full anaerobic digestion process. Such observations can be explained by differences in process parameters: anaerobic digestion is performed with more complex mixed cultures, lower substrate/inoculum and by-products/inoculum ratios and longer batch incubation times than dark fermentation. Finally, it has been reported that, during dark fermentation process, the presence of by-products could lead to a metabolic shift from H2-producing pathways (i.e. acetate and butyrate) to non-H2-producing pathways (i

  3. Bioconversion of woody biomass to biofuel and lignin co-product using sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL)

    Treesearch

    Junyong Zhu; Chao Zhang; Roland Gleisner; Carl Houtman; Xuejun Pan

    2016-01-01

    Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) promises to provide efficient bioconversion of woody biomass into bioethanol and lignin co-products. Results from several laboratory and pilot-scale studies are presented to demonstrate SPORL performance, with comparisons to competing technologies. Excellent ethanol yields of up to...

  4. Chapter 3: Atomistic Simulation of Lignocellulosic Biomass and Associated Cellulosomal Protein Complexes

    SciTech Connect

    Petridis, L.; Xu, J.; Crowley, M. F.; Smith, J. C.; Cheng, X.

    2010-01-01

    Computer simulations have been performed to obtain an atomic-level understanding of lignocellulose structure and the assembly of its associated cellulosomal protein complexes. First, a CHARMM molecular mechanics force field for lignin is derived and validated by performing a molecular dynamics simulation of a crystal of a lignin fragment molecule and comparing simulation-derived structural features with experimental results. Together with the existing force field for polysaccharides, this work provides the basis for full simulations of lignocellulose. Second, the underlying molecular mechanism governing the assembly of various cellulosomal modules is investigated by performing a novel free-energy calculation of the cohesin-dockerin dissociation. Our calculation indicates a free-energy barrier of {approx}17 kcal/mol and further reveals a stepwise dissociation pathway involving both the central {beta}-sheet interface and its adjacent solvent-exposed loop/turn regions clustered at both ends of the {beta}-barrel structure.

  5. Simultaneous saccharification, filtration and fermentation (SSFF): a novel method for bioethanol production from lignocellulosic biomass.

    PubMed

    Ishola, Mofoluwake M; Jahandideh, Arash; Haidarian, Behroz; Brandberg, Tomas; Taherzadeh, Mohammad J

    2013-04-01

    Simultaneous saccharification, filtration and fermentation (SSFF) was developed for lignocellulosic ethanol production. In SSFF, pretreated lignocellulosic material is enzymatically hydrolyzed in a reactor, while the suspension is continuously pumped through a cross-flow membrane. The retentate goes back to the hydrolysis vessel, while a clear sugar-rich filtrate continuously perfuses through the fermentation vessel before it is pumped back to the hydrolysis vessel. The capacity and life span of the cross-flow filter module was examined for 4 weeks using enzymatically hydrolyzed slurry, initially with 14.4% suspended solids, without clogging or fouling. An ethanol yield of 85.0% of the theoretical yield was obtained in SSFF and a flocculating strain of Saccharomyces cerevisiae was successfully reused for five cultivations of SSFF. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Cellulases immobilization on chitosan-coated magnetic nanoparticles: application for Agave Atrovirens lignocellulosic biomass hydrolysis.

    PubMed

    Sánchez-Ramírez, Jaquelina; Martínez-Hernández, José L; Segura-Ceniceros, Patricia; López, Guillermo; Saade, Hened; Medina-Morales, Miguel A; Ramos-González, Rodolfo; Aguilar, Cristóbal N; Ilyina, Anna

    2017-01-01

    In the present study, Trichoderma reesei cellulase was covalently immobilized on chitosan-coated magnetic nanoparticles using glutaraldehyde as a coupling agent. The average diameter of magnetic nanoparticles before and after enzyme immobilization was about 8 and 10 nm, respectively. The immobilized enzyme retained about 37 % of its initial activity, and also showed better thermal and storage stability than free enzyme. Immobilized cellulase retained about 80 % of its activity after 15 cycles of carboxymethylcellulose hydrolysis and was easily separated with the application of an external magnetic field. However, in this reaction, K m was increased eight times. The immobilized enzyme was able to hydrolyze lignocellulosic material from Agave atrovirens leaves with yield close to the amount detected with free enzyme and it was re-used in vegetal material conversion up to four cycles with 50 % of activity decrease. This provides an opportunity to reduce the enzyme consumption during lignocellulosic material saccharification for bioethanol production.

  7. Strategies for the production of cell wall-deconstructing enzymes in lignocellulosic biomass and their utilization for biofuel production.

    PubMed

    Park, Sang-Hyuck; Ong, Rebecca Garlock; Sticklen, Mariam

    2016-06-01

    Microbial cell wall-deconstructing enzymes are widely used in the food, wine, pulp and paper, textile, and detergent industries and will be heavily utilized by cellulosic biorefineries in the production of fuels and chemicals. Due to their ability to use freely available solar energy, genetically engineered bioenergy crops provide an attractive alternative to microbial bioreactors for the production of cell wall-deconstructing enzymes. This review article summarizes the efforts made within the last decade on the production of cell wall-deconstructing enzymes in planta for use in the deconstruction of lignocellulosic biomass. A number of strategies have been employed to increase enzyme yields and limit negative impacts on plant growth and development including targeting heterologous enzymes into specific subcellular compartments using signal peptides, using tissue-specific or inducible promoters to limit the expression of enzymes to certain portions of the plant or certain times, and fusion of amplification sequences upstream of the coding region to enhance expression. We also summarize methods that have been used to access and maintain activity of plant-generated enzymes when used in conjunction with thermochemical pretreatments for the production of lignocellulosic biofuels.

  8. Pretreatment of lignocellulosic biomass by cattle rumen fluid for methane production: Bacterial flora and enzyme activity analysis.

    PubMed

    Baba, Yasunori; Matsuki, Yu; Mori, Yumi; Suyama, Yoshihisa; Tada, Chika; Fukuda, Yasuhiro; Saito, Masanori; Nakai, Yutaka

    2017-01-29

    We attempted to develop a pretreatment method for methane fermentation of lignocellulosic biomass using cattle rumen fluid, treated as slaughterhouse waste. When rapeseed (Brassica napus L.) was added to the methane fermentation after being solubilized with rumen fluid, 1.5 times more methane was produced compared with untreated rapeseed. Analysis of the bacterial flora during rumen fluid treatment using the MiSeq next-generation sequencer showed that the predominant phylum shifted from Bacteroidetes, composed of amylolytic Prevotella spp., to Firmicutes, composed of cellulolytic and xylanolytic Ruminococcus spp., in only 6 h. In total, 7 cellulolytic, 25 cello-oligosaccharolytic, and 11 xylanolytic bacteria were detected after investigating the most abundant sequences of detected taxa. The relative abundance of two Ruminococcus species (Ruminococcus albus and R. flavefaciens), known as cellulolytic, cello-oligosaccharolytic, and xylanolytic bacteria, increased with increasing cellulose and hemicellulose degradation rates, and, finally, comprised 48% of all operational taxonomic units. The chronological observation of enzyme activities showed that cellulolytic and xylanolytic activities increased 6 h later, and that oligosaccharolytic activity increased 24 h later. This study detected six bacteria that participate in the degradation of aromatics derived from lignin, which have rarely been reported in rumen fluid. The constitution of the detected bacteria suggests that the aromatics were converted into acetate via benzoate. The list of microbes that cover all lignocellulose-degrading candidates will provide fundamental knowledge for future studies focusing on rumen microbes.

  9. Strategies for the production of cell wall-deconstructing enzymes in lignocellulosic biomass and their utilization for biofuel production

    DOE PAGES

    Park, Sang -Hyuck; Ong, Rebecca Garlock; Sticklen, Mariam

    2015-12-02

    Microbial cell wall-deconstructing enzymes are widely used in the food, wine, pulp and paper, textile, and detergent industries and will be heavily utilized by cellulosic biorefineries in the production of fuels and chemicals. Due to their ability to use freely available solar energy, genetically engineered bioenergy crops provide an attractive alternative to microbial bioreactors for the production of cell wall-deconstructing enzymes. This review article summarizes the efforts made within the last decade on the production of cell wall-deconstructing enzymes in planta for use in the deconstruction of lignocellulosic biomass. A number of strategies have been employed to increase enzyme yieldsmore » and limit negative impacts on plant growth and development including targeting heterologous enzymes into specific subcellular compartments using signal peptides, using tissue-specific or inducible promoters to limit the expression of enzymes to certain portions of the plant or certain times, and fusion of amplification sequences upstream of the coding region to enhance expression. As a result, we also summarize methods that have been used to access and maintain activity of plant-generated enzymes when used in conjunction with thermochemical pretreatments for the production of lignocellulosic biofuels.« less

  10. Simultaneous utilization of cellobiose, xylose, and acetic acid from lignocellulosic biomass for biofuel production by an engineered yeast platform.

    PubMed

    Wei, Na; Oh, Eun Joong; Million, Gyver; Cate, Jamie H D; Jin, Yong-Su

    2015-06-19

    The inability of fermenting microorganisms to use mixed carbon components derived from lignocellulosic biomass is a major technical barrier that hinders the development of economically viable cellulosic biofuel production. In this study, we integrated the fermentation pathways of both hexose and pentose sugars and an acetic acid reduction pathway into one Saccharomyces cerevisiae strain for the first time using synthetic biology and metabolic engineering approaches. The engineered strain coutilized cellobiose, xylose, and acetic acid to produce ethanol with a substantially higher yield and productivity than the control strains, and the results showed the unique synergistic effects of pathway coexpression. The mixed substrate coutilization strategy is important for making complete and efficient use of cellulosic carbon and will contribute to the development of consolidated bioprocessing for cellulosic biofuel. The study also presents an innovative metabolic engineering approach whereby multiple substrate consumption pathways can be integrated in a synergistic way for enhanced bioconversion.

  11. Selective oxidation of lignocellulosic biomass to formic acid and high-grade cellulose using tailor-made polyoxometalate catalysts.

    PubMed

    Albert, Jakob

    2017-06-27

    The main goal of this project was to identify and optimize tailor-made polyoxometalate catalysts for a fractionated oxidation of lignocellulosic biomass (i.e. wood and residues from sugar or paper industries) to produce formic acid (FA) and high-grade cellulose for further processing e.g. in white biotechnology to provide bio-ethanol. Homogeneous vanadium precursors like sodium metavanadate and vanadyl sulfate as well as Keggin-type polyoxometalates (POMs) and more exotic structures like Anderson-, Wells-Dawson- and Lindqvist-type POMs were screened for the desired catalytic performance. The most promising behaviour was found using the Lindqvist-type POM K5V3W3O19, showing for the first time in the literature a selective oxidation of only hemicellulose and lignin to formic acid, while the cellulose fraction was untrapped. However, this can only be a first step towards the project goal as low product yields were obtained.

  12. Two-temperature stage biphasic CO2-H2O pretreatment of lignocellulosic biomass at high solid loadings.

    PubMed

    Luterbacher, Jeremy S; Tester, Jefferson W; Walker, Larry P

    2012-06-01

    Most biomass pretreatment processes for monosaccharide production are run at low-solid concentration (<10 wt%) and use significant amounts of chemical catalysts. Biphasic CO(2) -H(2) O mixtures could provide a more sustainable pretreatment medium while using high-solid contents. Using a stirred reactor for high solids (40 wt%, biomass water mixture) biphasic CO(2)-H(2) O pretreatment of lignocellulosic biomass allowed us to explore the effects of particle size and mixing on mixed hardwood and switchgrass pretreatment. Subsequently, a two-temperature stage pretreatment was introduced. After optimization, a short high-temperature stage at 210°C (16 min for hardwood and 1 min for switchgrass) was followed by a long low-temperature stage at 160°C for 60 min. Glucan to glucose conversion yields of 83% for hardwood and 80% for switchgrass were obtained. Total molar sugar yields of 65% and 55% were obtained for wood and switchgrass, respectively, which consisted of a 10% points improvement over those obtained during our previous study despite a 10-fold increase in particle size. These yields are similar to those obtained with other major pretreatment technologies for wood and within 10% of major technologies for switchgrass despite the absence of chemical catalysts, the use of large particles (0.95 cm) and high solid contents (40 wt%).

  13. The Effects of Noncellulosic Compounds on the Nanoscale Interaction Forces Measured between Carbohydrate-Binding Module and Lignocellulosic Biomass.

    PubMed

    Arslan, Baran; Colpan, Mert; Ju, Xiaohui; Zhang, Xiao; Kostyukova, Alla; Abu-Lail, Nehal I

    2016-05-09

    The lack of fundamental understanding of the types of forces that govern how cellulose-degrading enzymes interact with cellulosic and noncellulosic components of lignocellulosic surfaces limits the design of new strategies for efficient conversion of biomass to bioethanol. In a step to improve our fundamental understanding of such interactions, nanoscale forces acting between a model cellulase-a carbohydrate-binding module (CBM) of cellobiohydrolase I (CBH I)-and a set of lignocellulosic substrates with controlled composition were measured using atomic force microscopy (AFM). The three model substrates investigated were kraft (KP), sulfite (SP), and organosolv (OPP) pulped substrates. These substrates varied in their surface lignin coverage, lignin type, and xylan and acetone extractives' content. Our results indicated that the overall adhesion forces of biomass to CBM increased linearly with surface lignin coverage with kraft lignin showing the highest forces among lignin types investigated. When the overall adhesion forces were decoupled into specific and nonspecific component forces via the Poisson statistical model, hydrophobic and Lifshitz-van der Waals (LW) forces dominated the binding forces of CBM to kraft lignin, whereas permanent dipole-dipole interactions and electrostatic forces facilitated the interactions of lignosulfonates to CBM. Xylan and acetone extractives' content increased the attractive forces between CBM and lignin-free substrates, most likely through hydrogen bonding forces. When the substrates treated differently were compared, it was found that both the differences in specific and nonspecific forces between lignin-containing and lignin-free substrates were the least for OPP. Therefore, cellulase enzymes represented by CBM would weakly bind to organosolv lignin. This will facilitate an easy enzyme recovery compared to other substrates treated with kraft or sulfite pulping. Our results also suggest that altering the surface hydrophobicity

  14. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass.

    PubMed

    Wang, Xu; Ma, Menggen; Liu, Z Lewis; Xiang, Quanju; Li, Xi; Liu, Na; Zhang, Xiaoping

    2016-08-01

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors (such as furfural and 5-hydroxymethylfurfural (HMF)) to less toxic corresponding alcohols. However, the reduction enzymes involved in this reaction remain largely unknown. In this study, we reported that an uncharacterized open reading frame PICST_72153 (putative GRE2) from S. stipitis was highly induced in response to furfural and HMF stresses. Overexpression of this gene in Saccharomyces cerevisiae improved yeast tolerance to furfural and HMF. GRE2 was identified as an aldehyde reductase which can reduce furfural to FM with either NADH or NADPH as the co-factor and reduce HMF to FDM with NADPH as the co-factor. This enzyme can also reduce multiple aldehydes to their corresponding alcohols. Amino acid sequence analysis indicated that it is a member of the subclass "intermediate" of the short-chain dehydrogenase/reductase (SDR) superfamily. Although GRE2 from S. stipitis is similar to GRE2 from S. cerevisiae in a three-dimensional structure, some differences were predicted. GRE2 from S. stipitis forms loops at D133-E137 and T143-N145 locations with two α-helices at E154-K157 and E252-A254 locations, different GRE2 from S. cerevisiae with an α-helix at D133-E137 and a β-sheet at T143-N145 locations, and two loops at E154-K157 and E252-A254 locations. This research provided guidelines for the study of other SDR enzymes from S. stipitis and other yeasts on tolerant mechanisms to aldehyde inhibitors derived from lignocellulosic biomass.

  15. Identification and characterization of core cellulolytic enzymes from Talaromyces cellulolyticus (formerly Acremonium cellulolyticus) critical for hydrolysis of lignocellulosic biomass

    DOE PAGES

    Inoue, Hiroyuki; Decker, Stephen R.; Taylor, Larry E.; ...

    2014-10-09

    Background: Enzymatic hydrolysis of pretreated lignocellulosic biomass is an essential process for the production of fermentable sugars for industrial use. A better understanding of fungal cellulase systems will provide clues for maximizing the hydrolysis of target biomass. Talaromyces cellulolyticus is a promising fungus for cellulase production and efficient biomass hydrolysis. Several cellulolytic enzymes purified from T. cellulolyticus were characterized in earlier studies, but the core enzymes critical for hydrolysis of lignocellulosic biomass remain unknown. Results: Six cellulolytic enzymes critical for the hydrolysis of crystalline cellulose were purified from T. cellulolyticus culture supernatant using an enzyme assay based on synergistic hydrolysismore » of Avicel. The purified enzymes were identified by their substrate specificities and analyses of trypsin-digested peptide fragments and were classified into the following glycosyl hydrolase (GH) families: GH3 (β-glucosidase, Bgl3A), GH5 (endoglucanase, Cel5A), GH6 (cellobiohydrolase II, Cel6A), GH7 (cellobiohydrolase I and endoglucanase, Cel7A and Cel7B, respectively), and GH10 (xylanase, Xyl10A). Hydrolysis of dilute acid-pretreated corn stover (PCS) with mixtures of the purified enzymes showed that Cel5A, Cel7B, and Xyl10A each had synergistic effects with a mixture of Cel6A and Cel7A. Cel5A seemed to be more effective in the synergistic hydrolysis of the PCS than Cel7B. The ratio of Cel5A, Cel6A, Cel7A, and Xyl10A was statistically optimized for the hydrolysis of PCS glucan in the presence of Bgl3A. The resultant mixture achieved higher PCS glucan hydrolysis at lower enzyme loading than a culture filtrate from T. cellulolyticus or a commercial enzyme preparation, demonstrating that the five enzymes play a role as core enzymes in the hydrolysis of PCS glucan. In Conclusion: Core cellulolytic enzymes in the T. cellulolyticus cellulase system were identified to Cel5A, Cel6A, Cel7A, Xyl10A, and Bgl3A

  16. Identification and characterization of core cellulolytic enzymes from Talaromyces cellulolyticus (formerly Acremonium cellulolyticus) critical for hydrolysis of lignocellulosic biomass

    SciTech Connect

    Inoue, Hiroyuki; Decker, Stephen R.; Taylor, Larry E.; Yano, Shinichi; Sawayama, Shigeki

    2014-10-09

    Background: Enzymatic hydrolysis of pretreated lignocellulosic biomass is an essential process for the production of fermentable sugars for industrial use. A better understanding of fungal cellulase systems will provide clues for maximizing the hydrolysis of target biomass. Talaromyces cellulolyticus is a promising fungus for cellulase production and efficient biomass hydrolysis. Several cellulolytic enzymes purified from T. cellulolyticus were characterized in earlier studies, but the core enzymes critical for hydrolysis of lignocellulosic biomass remain unknown. Results: Six cellulolytic enzymes critical for the hydrolysis of crystalline cellulose were purified from T. cellulolyticus culture supernatant using an enzyme assay based on synergistic hydrolysis of Avicel. The purified enzymes were identified by their substrate specificities and analyses of trypsin-digested peptide fragments and were classified into the following glycosyl hydrolase (GH) families: GH3 (β-glucosidase, Bgl3A), GH5 (endoglucanase, Cel5A), GH6 (cellobiohydrolase II, Cel6A), GH7 (cellobiohydrolase I and endoglucanase, Cel7A and Cel7B, respectively), and GH10 (xylanase, Xyl10A). Hydrolysis of dilute acid-pretreated corn stover (PCS) with mixtures of the purified enzymes showed that Cel5A, Cel7B, and Xyl10A each had synergistic effects with a mixture of Cel6A and Cel7A. Cel5A seemed to be more effective in the synergistic hydrolysis of the PCS than Cel7B. The ratio of Cel5A, Cel6A, Cel7A, and Xyl10A was statistically optimized for the hydrolysis of PCS glucan in the presence of Bgl3A. The resultant mixture achieved higher PCS glucan hydrolysis at lower enzyme loading than a culture filtrate from T. cellulolyticus or a commercial enzyme preparation, demonstrating that the five enzymes play a role as core enzymes in the hydrolysis of PCS glucan. In Conclusion: Core cellulolytic enzymes in the T. cellulolyticus cellulase system were identified to Cel5A, Cel6A, Cel7A, Xyl10A, and Bgl3A and

  17. Deletion of Caldicellulosiruptor bescii CelA reveals its crucial role in the deconstruction of lignocellulosic biomass

    DOE PAGES

    Young, Jenna; Chung, Daehwan; Bomble, Yannick J.; ...

    2014-10-09

    Background: Members of the bacterial genus Caldicellulosiruptor are the most thermophilic cellulolytic organisms described to date, and have the ability to grow on lignocellulosic biomass without conventional pretreatment. Different species vary in their abilities to degrade cellulose, and the presence of CelA, a bifunctional glycoside hydrolase that contains a Family 48 and a Family 9 catalytic domain, correlates well with cellulolytic ability in members of this genus. For example, C. hydrothermalis, which does not contain a CelA homolog, or a GH48 Family or GH9 Family glycoside hydrolase, is the least cellulolytic of the Caldicellulosiruptor species so far described. C. bescii,more » which contains CelA and expresses it constitutively, is among the most cellulolytic. In fact, CelA is the most abundant extracellular protein produced in C. bescii. The enzyme contains two catalytic units, a Family 9A-CBM3c processive endoglucanase and a Family 48 exoglucanase, joined by two Family 3b carbohydrate-binding domains. Although there are two non-reducing end-specific Family 9 and three reducing end-specific Family 48 glycoside hydrolases (producing primarily glucose and cellobiose; and cellobiose and cellotriose, respectively) in C. bescii, CelA is the only protein that combines both enzymatic activities. Results: A deletion of the celA gene resulted in a dramatic reduction in the microorganism’s ability to grow on crystalline cellulose (Avicel) and diminished growth on lignocellulosic biomass. A comparison of the overall endoglucanase and exoglucanase activities of the mutant compared with the wild-type suggests that the loss of the endoglucanase activity provided by the GH9 family domain is perhaps compensated for by other enzymes produced by the cell. In contrast, it appears that no other enzymes in the C. bescii secretome can compensate for the loss of exoglucanase activity. The change in enzymatic activity in the celA mutant resulted in a 15-fold decrease in

  18. Deletion of Caldicellulosiruptor bescii CelA reveals its crucial role in the deconstruction of lignocellulosic biomass

    SciTech Connect

    Young, Jenna; Chung, Daehwan; Bomble, Yannick J.; Himmel, Michael E.; Westpheling, Janet

    2014-10-09

    Background: Members of the bacterial genus Caldicellulosiruptor are the most thermophilic cellulolytic organisms described to date, and have the ability to grow on lignocellulosic biomass without conventional pretreatment. Different species vary in their abilities to degrade cellulose, and the presence of CelA, a bifunctional glycoside hydrolase that contains a Family 48 and a Family 9 catalytic domain, correlates well with cellulolytic ability in members of this genus. For example, C. hydrothermalis, which does not contain a CelA homolog, or a GH48 Family or GH9 Family glycoside hydrolase, is the least cellulolytic of the Caldicellulosiruptor species so far described. C. bescii, which contains CelA and expresses it constitutively, is among the most cellulolytic. In fact, CelA is the most abundant extracellular protein produced in C. bescii. The enzyme contains two catalytic units, a Family 9A-CBM3c processive endoglucanase and a Family 48 exoglucanase, joined by two Family 3b carbohydrate-binding domains. Although there are two non-reducing end-specific Family 9 and three reducing end-specific Family 48 glycoside hydrolases (producing primarily glucose and cellobiose; and cellobiose and cellotriose, respectively) in C. bescii, CelA is the only protein that combines both enzymatic activities. Results: A deletion of the celA gene resulted in a dramatic reduction in the microorganism’s ability to grow on crystalline cellulose (Avicel) and diminished growth on lignocellulosic biomass. A comparison of the overall endoglucanase and exoglucanase activities of the mutant compared with the wild-type suggests that the loss of the endoglucanase activity provided by the GH9 family domain is perhaps compensated for by other enzymes produced by the cell. In contrast, it appears that no other enzymes in the C. bescii secretome can compensate for the loss of exoglucanase activity. The change in enzymatic activity in the celA mutant resulted in a 15-fold decrease in sugar

  19. Valorization of untreated rice bran towards bioflocculant using a lignocellulose-degrading strain and its use in microalgal biomass harvest.

    PubMed

    Liu, Cong; Hao, Yan; Jiang, Jihong; Liu, Weijie

    2017-01-01

    Microalgae are currently considered as a promising feedstock for the production of biofuels and high-value products. However, the efficient harvest of microalgal biomasses from their culture broth is a major challenge. The harvesting of algal biomass by flocculation combined with gravity sedimentation is more convenient and cost-effective than traditional methods such as centrifugation and filtration. Compared to inorganic and chemically synthetic flocculants, bioflocculants are a suitable choice for microalgal harvest due to their biodegradable and nontoxic properties. Nonetheless, the high production costs associated with expensive substrates hinder the commercial applications of bioflocculants. Previous studies have shown that the hydrolysates of lignocellulosic biomasses from dilute acid hydrolysis can be utilized as an inexpensive carbon source for the production of bioflocculants. However, the toxic by-products generated in the dilute acid hydrolysis step limit the efficiency of subsequent fermentation. The strains that produce bioflocculants by using untreated lignocellulosic materials can circumvent the pretreatment process, as well as promote the application of bioflocculants in microalgal harvest. Under alkaline fermentation conditions, the alkaliphilic strain Bacillus agaradhaerens C9 secreted 1.69 IU/mL of alkali-tolerant xylanase and 0.06 IU/mL of cellulase, indicating that this particular strain can efficiently convert untreated rice bran into bioflocculant (RBBF-C9), thereby circumventing rice bran pretreatment for downstream fermentation. The optimal fermentation conditions that result in the highest bioflocculant yield (12.94 g/L) were as follows: 20 g/L of untreated rice bran, 3 g/L of yeast extract, and 20 g/L of Na2CO3 at 37 °C for 24 h. RBBF-C9 contained 74.12% polysaccharides and 4.51% proteins, and was estimated to be 137 kDa. Furthermore, the bioflocculant RBBF-C9 exhibited good flocculating efficiency (91.05%) of oil alga

  20. Enhanced Solid-State Biogas Production from Lignocellulosic Biomass by Organosolv Pretreatment

    PubMed Central

    Mirmohamadsadeghi, Safoora; Zamani, Akram; Horváth, Ilona Sárvári

    2014-01-01

    Organosolv pretreatment was used to improve solid-state anaerobic digestion (SSAD) for methane production from three different lignocellulosic substrates (hardwood elm, softwood pine, and agricultural waste rice straw). Pretreatments were conducted at 150 and 180°C for 30 and 60 min using 75% ethanol solution as an organic solvent with addition of sulfuric acid as a catalyst. The statistical analyses showed that pretreatment temperature was the significant factor affecting methane production. Optimum temperature was 180°C for elmwood while it was 150°C for both pinewood and rice straw. Maximum methane production was 152.7, 93.7, and 71.4 liter per kg carbohydrates (CH), which showed up to 32, 73, and 84% enhancement for rice straw, elmwood, and pinewood, respectively, compared to those from the untreated substrates. An inverse relationship between the total methane yield and the lignin content of the substrates was observed. Kinetic analysis of the methane production showed that the process followed a first-order model for all untreated and pretreated lignocelluloses. PMID:25243134

  1. Accessory enzymes influence cellulase hydrolysis of the model substrate and the realistic lignocellulosic biomass.

    PubMed

    Sun, Fubao Fuebiol; Hong, Jiapeng; Hu, Jinguang; Saddler, Jack N; Fang, Xu; Zhang, Zhenyu; Shen, Song

    2015-11-01

    The potential of cellulase enzymes in the developing and ongoing "biorefinery" industry has provided a great motivation to develop an efficient cellulase mixture. Recent work has shown how important the role that the so-called accessory enzymes can play in an effective enzymatic hydrolysis. In this study, three newest Novozymes Cellic CTec cellulase preparations (CTec 1/2/3) were compared to hydrolyze steam pretreated lignocellulosic substrates and model substances at an identical FPA loading. These cellulase preparations were found to display significantly different hydrolytic performances irrelevant with the FPA. And this difference was even observed on the filter paper itself when the FPA based assay was revisited. The analysis of specific enzyme activity in cellulase preparations demonstrated that different accessory enzymes were mainly responsible for the discrepancy of enzymatic hydrolysis between diversified substrates and various cellulases. Such the active role of accessory enzymes present in cellulase preparations was finally verified by supplementation with β-glucosidase, xylanase and lytic polysaccharide monooxygenases AA9. This paper provides new insights into the role of accessory enzymes, which can further provide a useful reference for the rational customization of cellulase cocktails in order to realize an efficient conversion of natural lignocellulosic substrates. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Continuous enzymatic hydrolysis of lignocellulosic biomass with simultaneous detoxification and enzyme recovery.

    PubMed

    Gurram, Raghu N; Menkhaus, Todd J

    2014-07-01

    Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

  3. Enhanced lignocellulosic biomass hydrolysis by oxidative lytic polysaccharide monooxygenases (LPMOs) GH61 from Gloeophyllum trabeum.

    PubMed

    Jung, Sera; Song, Younho; Kim, Ho Myeong; Bae, Hyeun-Jong

    2015-09-01

    Lignocellulose is a renewable resource that is extremely abundant, and the complete enzymatic hydrolysis of lignocellulose requires a cocktail containing a variety of enzyme groups that act synergistically. The hydrolysis efficiency can be improved by introducing glycoside hydrolase 61 (GH61), a new enzyme that belongs to the auxiliary activity family 9 (AA9). GH61was isolated from Gloeophyllum trabeum and cleaves the glycosidic bonds on the cellulose surface via oxidation of various carbons. In this study, we investigated the properties of GH61. GtGH61 alone did not exhibit any notable activity, but the synergistic activity of GtGH61 with xylanase (GtXyl10G) or cellulase (GtCel5B) showed efficient bioconversion rates of 56 and 174% in pretreated kenaf (Hibiscus cannabinus L.) and oak (Quercus spp.), respectively. Furthermore, the GtGH61 activity was strongly accelerated in the presence of cobalt Co(2+). Enzyme cocktails (GtXyl10G, GtCel5B, and GtGH61) increased the amount of sugar released by 7 and 6% for pretreated oak and kenaf, respectively, and the addition of Co(2+) stimulated bioconversion by 12 and 11% in pretreated oak and kenaf, respectively. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Qualitative and quantitative analysis of lignocellulosic biomass using infrared techniques: A mini-review

    USDA-ARS?s Scientific Manuscript database

    Current wet chemical methods for biomass composition analysis using two-step sulfuric acid hydrolysis are time-consuming, labor-intensive, and unable to provide structural information about biomass. Infrared techniques provide fast, low-cost analysis, are non-destructive, and have shown promising re...

  5. Nanostructured enzyme assemblies for lignocellulosic biomass breakdown for bioproduct and bioenergy applications

    USDA-ARS?s Scientific Manuscript database

    Sufficient cellulosic biomass can be harvested to meet a significant fraction of America’s future liquid fuel needs without compromising the nation’s food supply. Low efficiency or high cost for conversion of cellulosic biomass to fermentable sugars is a major barrier to this goal. We will develop s...

  6. Tolerant ethanologenic yeast for low-cost lignocellulosic biomass conversion to ethanol

    USDA-ARS?s Scientific Manuscript database

    One of the technical challenges for biomass conversion to ethanol is the generation of inhibitors during biomass pretreatment that interfere with microbial growth and subsequent fermentation. These inhibitors are formed in dehydration of pentoses and hexoses derived from degradation of cellulose an...

  7. Suspension Dynamics of Liquefied Lignocellulosic Biomass in Pipeflow using Echo Particle Image Velocimetry

    NASA Astrophysics Data System (ADS)

    Demarchi, Nicholas; White, Christopher

    2015-11-01

    Echo particle image velocimetry (EPIV) is used to acquire planar fields of velocity in pipeflow of liquefied biomass. The biomass used is acid washed corn stover liquefied by enzymatic hydrolysis. The liquefaction process produces a complex multiphase fluid suspension with a microstructure consisting of insoluble solid particles dispersed within a continuous liquid phase. The solid particles are generally heavier than the liquid phase, non-spherical, and distributed over a wide range of aspect ratios and sizes. Batches of liquefied biomass are produced at incremental mass loadings doubling from 1.5% to 12%. The rheology, microstructure, and solid particle settling velocities of the liquefied biomass as a function of mass loading is first quantified. Next, EPIV is used to measure and quantify the flow dynamics of liquefied biomass suspensions under laminar pressure driven pipeflow conditions. Finally, Information gathered from the experimental data is used to simulate particle settling rates and predict the particle physics under the same pipeflow conditions.?

  8. Peracetic acid-ionic liquid pretreatment to enhance enzymatic saccharification of lignocellulosic biomass.

    PubMed

    Uju; Abe, Kojiro; Uemura, Nobuyuki; Oshima, Toyoji; Goto, Masahiro; Kamiya, Noriho

    2013-06-01

    To enhance enzymatic saccharification of pine biomass, the pretreatment reagents peracetic acid (PAA) and ionic liquid (IL) were validated in single reagent pretreatments or combination pretreatments with different sequences. In a 1h saccharification, 5-25% cellulose conversion was obtained from the single pretreatment of PAA or IL. In contrast, a marked enhancement in conversion rates was achieved by PAA-IL combination pretreatments (45-70%). The PAA followed by IL (PAA+IL) pretreatment sequence was the most effective for preparing an enzymatic digestible regenerated biomass with 250-fold higher glucose formation rates than untreated biomass and 2- to 12-fold higher than single pretreatments with PAA or IL alone. Structural analysis confirmed that this pretreatment resulted in biomass with highly porous structural fibers associated with the reduction of lignin content and acetyl groups. Using the PAA+IL sequence, biomass loading in the pretreatment step can be increased from 5% to 15% without significant decrease in cellulose conversion.

  9. Techno-economic Analysis for the Thermochemical Conversion of Lignocellulosic Biomass to Ethanol via Acetic Acid Synthesis

    SciTech Connect

    Zhu, Yunhua; Jones, Susanne B.

    2009-04-01

    Biomass is a renewable energy resource that can be converted into liquid fuel suitable for transportation applications. As a widely available biomass form, lignocellulosic biomass can have a major impact on domestic transportation fuel supplies and thus help meet the Energy Independence and Security Act renewable energy goals (U.S. Congress 2007). This study performs a techno-economic analysis of the thermo chemical conversion of biomass to ethanol, through methanol and acetic acid, followed by hydrogenation of acetic acid to ethanol. The conversion of syngas to methanol and methanol to acetic acid are well-proven technologies with high conversions and yields. This study was undertaken to determine if this highly selective route to ethanol could provide an already established economically attractive route to ethanol. The feedstock was assumed to be wood chips at 2000 metric ton/day (dry basis). Two types of gasification technologies were evaluated: an indirectly-heated gasifier and a directly-heated oxygen-blown gasifier. Process models were developed and a cost analysis was performed. The carbon monoxide used for acetic acid synthesis from methanol and the hydrogen used for hydrogenation were assumed to be purchased and not derived from the gasifier. Analysis results show that ethanol selling prices are estimated to be $2.79/gallon and $2.81/gallon for the indirectly-heated gasifier and the directly-heated gasifier systems, respectively (1stQ 2008$, 10% ROI). These costs are above the ethanol market price for during the same time period ($1.50 - $2.50/gal). The co-production of acetic acid greatly improves the process economics as shown in the figure below. Here, 20% of the acetic acid is diverted from ethanol production and assumed to be sold as a co-product at the prevailing market prices ($0.40 - $0.60/lb acetic acid), resulting in competitive ethanol production costs.

  10. Structural reorganisation of cellulose fibrils in hydrothermally deconstructed lignocellulosic biomass and relationships with enzyme digestibility

    PubMed Central

    2013-01-01

    Background The investigation of structural organisation in lignocellulose materials is important to understand changes in cellulase accessibility and reactivity resulting from hydrothermal deconstruction, to allow development of strategies to maximise bioethanol process efficiencies. To achieve progress, wheat straw lignocellulose and comparative model wood cellulose were characterised following increasing severity of hydrothermal treatment. Powder and fibre wide-angle X-ray diffraction techniques were employed (WAXD), complemented by enzyme kinetic measurements up to high conversion. Results Evidence from WAXD indicated that cellulose fibrils are not perfectly crystalline. A reduction in fibril crystallinity occurred due to hydrothermal treatment, although dimensional and orientational data showed that fibril coherency and alignment were largely retained. The hypothetical inter-fibril spacing created by hydrothermal deconstruction of straw was calculated to be insufficient for complete access by cellulases, although total digestion of cellulose in both treated straw and model pulp was observed. Both treated straw and model pulps were subjected to wet mechanical attrition, which caused separation of smaller fibril aggregates and fragments, significantly increasing enzyme hydrolysis rate. No evidence from WAXD measurements was found for preferential hydrolysis of non-crystalline cellulose at intermediate extent of digestion, for both wood pulp and hydrothermally treated straw. Conclusions The increased efficiency of enzyme digestion of cellulose in the lignocellulosic cell wall following hydrothermal treatment is a consequence of the improved fibril accessibility due to the loss of hemicellulose and disruption of lignin. However, incomplete accessibility of cellulase at the internal surfaces of fibrillar aggregates implies that etching type mechanisms will be important in achieving complete hydrolysis. The reduction in crystalline perfection following hydrothermal

  11. Pretreatment of garden biomass using Fenton's reagent: influence of Fe(2+) and H2O2 concentrations on lignocellulose degradation.

    PubMed

    Bhange, Vivek P; William, Spm Prince; Sharma, Abhinav; Gabhane, Jagdish; Vaidya, Atul N; Wate, Satish R

    2015-01-01

    Garden biomass (GB) is defined as low density and heterogeneous waste fraction of garden rubbish like grass clippings, pruning, flowers, branches, weeds; roots. GB is generally different from other types of biomass. GB is mostly generated through maintenance of green areas. GB can be processed for bio energy production as it contains considerably good amount of cellulose and hemicellulose. However, pretreatment is necessary to delignify and facilitate disruption of cellulosic moiety. The aim of the present investigation was to pretreat GB using Fenton's reagent and to study the influence of Fe(2+) and H2O2 concentrations on degradation of lignin and cellulose. The data were statistically analyzed using ANOVA and numerical point prediction tool of MINITAB RELEASE 14 to optimize different process variables such as temperature, concentration of Fe(2+) and H2O2. The results of the present investigation showed that Fenton's reagent was effective on GB, however, concentration of Fe(2+) and H2O2 play crucial role in determining the efficiency of pretreatment. An increase in H2O2 concentration in Fenton's reagent significantly increased the rate of cellulose and lignin degradation in contrast to increasing concentration of Fe(2+) ion which led to a decrease in lignocellulosic degradation.

  12. An overview of key pretreatment processes employed for bioconversion of lignocellulosic biomass into biofuels and value added products.

    PubMed

    Chaturvedi, Venkatesh; Verma, Pradeep

    2013-10-01

    The hunt for alternative sources of energy generation that are inexpensive, ecofriendly, renewable and can replace fossil fuels is on, owing to the increasing demands of energy. One approach in this direction is the conversion of plant residues into biofuels wherein lignocellulose, which forms the structural framework of plants consisting of cellulose, hemicellulose and lignin, is first broken down and hydrolyzed into simple fermentable sugars, which upon fermentation form biofuels such as ethanol. A major bottleneck is to disarray lignin which is present as a protective covering and makes cellulose and hemicellulose recalcitrant to enzymatic hydrolysis. A number of biomass deconstruction or pretreatment processes (physical, chemical and biological) have been used to break the structural framework of plants and depolymerize lignin. This review surveys and discusses some major pretreatment processes pertaining to the pretreatment of plant biomass, which are used for the production of biofuels and other value added products. The emphasis is given on processes that provide maximum amount of sugars, which are subsequently used for the production of biofuels.

  13. Production of polyhydroxybutyrate in switchgrass, a value-added co-product in an important lignocellulosic biomass crop.

    PubMed

    Somleva, Maria N; Snell, Kristi D; Beaulieu, Julie J; Peoples, Oliver P; Garrison, Bradley R; Patterson, Nii A

    2008-09-01

    Polyhydroxyalkanoate bio-based plastics made from renewable resources can reduce petroleum consumption and decrease plastic waste disposal issues as they are inherently biodegradable in soil, compost and marine environments. In this paper, the successful engineering of the biomass crop switchgrass (Panicum virgatum L.) for the synthesis of polyhydroxybutyrate (PHB) is reported. Polymer production was monitored in more than 400 primary transformants grown under in vitro and glasshouse conditions. Plants containing up to 3.72% dry weight of PHB in leaf tissues and 1.23% dry weight of PHB in whole tillers were obtained. Results from the analysis of the polymer distribution at the cellular and whole plant levels are presented, and target areas for the improvement of PHB production are highlighted. Polymer accumulation was also analysed in the T(1) generation obtained from controlled crosses of transgenic plants. This study presents the first successful expression of a functional multigene pathway in switchgrass, and demonstrates that this high-yielding biomass crop is amenable to the complex metabolic engineering strategies necessary to produce high-value biomaterials with lignocellulose-derived biofuels.

  14. Effect of dilute acid pretreatment severity on the bioconversion efficiency of Phalaris aquatica L. lignocellulosic biomass into fermentable sugars.

    PubMed

    Pappas, Ioannis A; Koukoura, Zoi; Tananaki, Chrisoula; Goulas, Christos

    2014-08-01

    The effect of dilute acid pretreatment severity on the bioconversion efficiency of Phalaris aquatica lignocellulosic biomass into fermentable sugar monomers was studied. The pretreatment conditions were expressed in a combined severity factor (CSF), ranged from 0.13 to 1.16. The concentration of xylose and total monomeric sugars released from hemicellulose increased with pretreatment as the CSF increased. Dilute acid pretreatment resulted in about 1.7-fold increase in glucose release relative to the untreated biomass, while CSF was positively correlated with glucose recovery. A maximum glucose yield of 85.05% was observed at high severity values (i.e. CSF 1.16) after 72 h. The total amount of sugars released (i.e. xylose and glucose) was increased with pretreatment severity and a maximum conversion efficiency of 76.1% of structural carbohydrates was obtained at a CSF=1. Our data indicated that Phalaris aquatica L. is an alternative bioethanol feedstock and that hemicellulose removal promotes glucose yield.

  15. Bioconversion potential of Trichoderma viride HN1 cellulase for a lignocellulosic biomass Saccharum spontaneum.

    PubMed

    Iqtedar, Mehwish; Nadeem, Mohammad; Naeem, Hira; Abdullah, Roheena; Naz, Shagufta; Qurat ul Ain Syed; Kaleem, Afshan

    2015-01-01

    The industrialisation of lignocellulose conversion is impeded by expensive cellulase enzymes required for saccharification in bioethanol production. Current research undertakes cellulase production from pretreated Saccharum spontaneum through Trichoderma viride HN1 under submerged fermentation conditions. Pretreatment of substrate with 2% NaOH resulted in 88% delignification. Maximum cellulase production (2603 ± 16.39 U/mL/min carboxymethyl cellulase and 1393 ± 25.55 U/mL/min FPase) was achieved at 6% substrate at pH 5.0, with 5% inoculum, incubated at 35°C for 120 h of fermentation period. Addition of surfactant, Tween 80 and metal ion Mn(+2), significantly enhanced cellulase yield. This study accounts proficient cellulase yield through process optimisation by exploiting cheaper substrate to escalate their commercial endeavour.

  16. Ethanol production from maize silage as lignocellulosic biomass in anaerobically digested and wet-oxidized manure.

    PubMed

    Oleskowicz-Popiel, Piotr; Lisiecki, Przemyslaw; Holm-Nielsen, Jens Bo; Thomsen, Anne Belinda; Thomsen, Mette Hedegaard

    2008-09-01

    In this communication, pretreatment of the anaerobically digested (AD) manure and the application of the pretreated AD manure as liquid medium for the simultaneous saccharification and fermentation (SSF) were described. Furthermore, fermentation of pretreated maize silage and wheat straw was investigated using 2l bioreactors. Wet oxidation performed for 20 min at 121 degrees C was found as the most suitable pretreatment conditions for AD manure. High ammonia concentration and significant amount of macro- and micro-nutrients in the AD manure had a positive influence on the ethanol fermentation. No extra nitrogen source was needed in the fermentation broth. It was shown that the AD manure could successfully substitute process water in SSF of pretreated lignocellulosic fibres. Theoretical ethanol yields of 82% were achieved, giving 30.8 kg ethanol per 100 kg dry mass of maize silage.

  17. Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

    PubMed

    Li, Dalin; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

    2015-02-01

    Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described.

  18. Butyric acid production from lignocellulosic biomass hydrolysates by engineered Clostridium tyrobutyricum overexpressing xylose catabolism genes for glucose and xylose co-utilization.

    PubMed

    Fu, Hongxin; Yang, Shang-Tian; Wang, Minqi; Wang, Jufang; Tang, I-Ching

    2017-06-01

    Clostridium tyrobutyricum can utilize glucose and xylose as carbon source for butyric acid production. However, xylose catabolism is inhibited by glucose, hampering butyric acid production from lignocellulosic biomass hydrolysates containing both glucose and xylose. In this study, an engineered strain of C. tyrobutyricum Ct-pTBA overexpressing heterologous xylose catabolism genes (xylT, xylA, and xylB) was investigated for co-utilizing glucose and xylose present in hydrolysates of plant biomass, including soybean hull, corn fiber, wheat straw, rice straw, and sugarcane bagasse. Compared to the wild-type strain, Ct-pTBA showed higher xylose utilization without significant glucose catabolite repression, achieving near 100% utilization of glucose and xylose present in lignocellulosic biomass hydrolysates in bioreactor at pH 6. About 42.6g/L butyrate at a productivity of 0.56g/L·h and yield of 0.36g/g was obtained in batch fermentation, demonstrating the potential of C. tyrobutyricum Ct-pTBA for butyric acid production from lignocellulosic biomass hydrolysates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Prediction of sugar yields during hydrolysis of lignocellulosic biomass using artificial neural network modeling.

    PubMed

    Vani, Sankar; Sukumaran, Rajeev Kumar; Savithri, Sivaraman

    2015-01-01

    The present investigation was carried out to study application of ANN as a tool for predicting sugar yields of pretreated biomass during hydrolysis process at various time intervals. Since it is known that biomass loading and particle size influences the rheology and mass transfer during hydrolysis process, these two parameters were chosen for investigating the efficiency of hydrolysis. Alkali pretreated rice straw was used as the model feedstock in this study and biomass loadings were varied from 10% to 18%. Substrate particle sizes used were <0.5mm, 0.5-1mm, >1mm and mixed size. Effectiveness of hydrolysis was strongly influenced by biomass loadings, whereas particle size did not have any significant impact on sugar yield. Higher biomass loadings resulted in higher sugar concentration in the hydrolysates. Optimum hydrolysis conditions predicted were 10 FPU/g cellulase, 5 IU/g BGL, 7500 U/g xylanase, 18% biomass loading and mixed particle size with reaction time between 12-28 h.

  20. Novel Magnetic Cross-Linked Cellulase Aggregates with a Potential Application in Lignocellulosic Biomass Bioconversion.

    PubMed

    Jia, Junqi; Zhang, Weiwei; Yang, Zengjie; Yang, Xianling; Wang, Na; Yu, Xiaoqi

    2017-02-10

    The utilization of renewable biomass resources to produce high-value chemicals by enzymatic processes is beneficial for alternative energy production, due to the accelerating depletion of fossil fuels. As immobilization techniques can improve enzyme stability and reusability, a novel magnetic cross-linked cellulase aggregate has been developed and applied for biomass bioconversion. The crosslinked aggregates could purify and immobilize enzymes in a single operation, and could then be combined with magnetic nanoparticles (MNPs), which provides easy separation of the materials. The immobilized cellulase showed a better activity at a wider temperature range and pH values than that of the free cellulase. After six cycles of consecutive reuse, the immobilized cellulase performed successful magnetic separation and retained 74% of its initial activity when carboxylmethyl cellulose (CMC) was used as the model substrate. Furthermore, the structure and morphology of the immobilized cellulase were studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, the immobilized cellulase was shown to hydrolyze bamboo biomass with a yield of 21%, and was re-used in biomass conversion up to four cycles with 38% activity retention, which indicated that the immobilized enzyme has good potential for biomass applications.

  1. Development of a Membrane-Based Separation Process for the Continuous Enzymatic Saccharification of Lignocellulosic Biomass; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Adhikari, B.; Pellegrino, J.; Stickel, J.; Sievers, J.

    2014-04-29

    We are currently evaluating the feasibility of performing continuous enzymatic hydrolysis of lignocellulosic biomass to product sugars using a membrane-assisted reaction/separation process. The overarching technical goals are to continuously remove the sugars—this lowers product feedback inhibition—retain and recycle active enzyme, and continuously recover the co-product of lignin. Experimental d d d currently evaluating the feasibility of performing continuous enzymatic hydrolysis of lignocellulosic biomass to product sugars using a membrane-assisted reaction/separation process. The overarching technical goals are to continuously remove the sugars -- this lowers product feedback inhibition --retain and recycle active enzyme, and continuously recover the co-product of lignin.

  2. Liquid hot water pretreatment of lignocellulosic biomass for bioethanol production accompanying with high valuable products.

    PubMed

    Zhuang, Xinshu; Wang, Wen; Yu, Qiang; Qi, Wei; Wang, Qiong; Tan, Xuesong; Zhou, Guixiong; Yuan, Zhenhong

    2016-01-01

    Pretreatment is an essential prerequisite to overcome recalcitrance of biomass and enhance the ethanol conversion efficiency of polysaccharides. Compared with other pretreatment methods, liquid hot water (LHW) pretreatment not only reduces the downstream pressure by making cellulose more accessible to the enzymes but minimizes the formation of degradation products that inhibit the growth of fermentative microorganisms. Herein, this review summarized the improved LHW process for different biomass feedstocks, the decomposition behavior of biomass in the LHW process, the enzymatic hydrolysis of LHW-treated substrates, and production of high value-added products and ethanol. Moreover, a combined process producing ethanol and high value-added products was proposed basing on the works of Guangzhou Institute of Energy Conversion to make LHW pretreatment acceptable in the biorefinery of cellulosic ethanol.

  3. Biosorption of alpacide blue from aqueous solution by lignocellulosic biomass: Luffa cylindrica fibers.

    PubMed

    Kesraoui, Aida; Moussa, Asma; Ali, Ghada Ben; Seffen, Mongi

    2016-08-01

    The aim of the present work is to develop an effective and inexpensive pollutant-removal technology using lignocellulosic fibers: Luffa cylindrica, for the biosorption of an anionic dye: alpacide blue. The influence of some experimental parameters such as pH, temperature, initial concentration of the polluted solution, and mass of the sorbent L. cylindrica on the biosorption of alpacide blue by L. cylindrica fibers has been investigated. Optimal parameters for maximum quantity of biosorption dye were achieved after 2 h of treatment in a batch system using an initial dye concentration of 20 mg/L, a mass of 1 g of L. cylindrica fibers, and pH 2. In these conditions, the quantity of dye retained is 2 mg/g and the retention rate is 78 %. Finally, a mathematical modeling of kinetics and isotherms has been used for mathematical modeling; the model of pseudo-second order is more appropriate to describe this phenomenon of biosorption. Concerning biosorption isotherms, the Freundlich model is the most appropriate for a biosorption of alpacide blue dye by L. cylindrica fibers.

  4. Empirical evaluation of inhibitory product, substrate, and enzyme effects during the enzymatic saccharification of lignocellulosic biomass.

    PubMed

    Smith, Benjamin T; Knutsen, Jeffrey S; Davis, Robert H

    2010-05-01

    The cellulose hydrolysis kinetics during batch enzymatic saccharification are typified by a rapid initial rate that subsequently decays, resulting in incomplete conversion. Previous studies suggest that changes associated with the solution, substrate, or enzymes may be responsible. In this work, kinetic experiments were conducted to determine the relative magnitude of these effects. Pretreated corn stover (PCS) was used as a lignocellulosic substrate likely to be found in a commercial saccharification process, while Avicel and Kraft lignin were used to create model substrates. Glucose inhibition was observed by spiking the reaction slurry with glucose during initial-rate experiments. Increasing the glucose concentration from 7 to 48 g/L reduced the cellulose conversion rate by 94%. When product sugars were removed using ultrafiltration with a 10 kDa membrane, the glucose-based conversion increased by 9.5%. Reductions in substrate reactivity with conversion were compared directly by saccharifying PCS and Avicel substrates that had been pre-reacted to different conversions. Reaction of substrate with a pre-conversion of 40% resulted in about 40% reduction in the initial rate of saccharification, relative to fresh substrate with identical cellulose concentration. Overall, glucose inhibition and reduced substrate reactivity appear to be dominant factors, whereas minimal reductions of enzyme activity were observed.

  5. High removal efficacy of Hg(II) and MeHg(II) ions from aqueous solution by organoalkoxysilane-grafted lignocellulosic waste biomass.

    PubMed

    Saman, Norasikin; Johari, Khairiraihanna; Song, Shiow-Tien; Kong, Helen; Cheu, Siew-Chin; Mat, Hanapi

    2017-03-01

    An effective organoalkoxysilanes-grafted lignocellulosic waste biomass (OS-LWB) adsorbent aiming for high removal towards inorganic and organic mercury (Hg(II) and MeHg(II)) ions was prepared. Organoalkoxysilanes (OS) namely mercaptoproyltriethoxylsilane (MPTES), aminopropyltriethoxylsilane (APTES), aminoethylaminopropyltriethoxylsilane (AEPTES), bis(triethoxysilylpropyl) tetrasulfide (BTESPT), methacrylopropyltrimethoxylsilane (MPS) and ureidopropyltriethoxylsilane (URS) were grafted onto the LWB using the same conditions. The MPTES grafted lignocellulosic waste biomass (MPTES-LWB) showed the highest adsorption capacity towards both mercury ions. The adsorption behavior of inorganic and organic mercury ions (Hg(II) and MeHg(II)) in batch adsorption studies shows that it was independent with pH of the solutions and dependent on initial concentration, temperature and contact time. The maximum adsorption capacity of Hg(II) was greater than MeHg(II) which respectively followed the Temkin and Langmuir models. The kinetic data analysis showed that the adsorptions of Hg(II) and MeHg(II) onto MPTES-LWB were respectively controlled by the physical process of film diffusion and the chemical process of physisorption interactions. The overall mechanism of Hg(II) and MeHg(II) adsorption was a combination of diffusion and chemical interaction mechanisms. Regeneration results were very encouraging especially for the Hg(II); this therefore further demonstrated the potential application of organosilane-grafted lignocellulosic waste biomass as low-cost adsorbents for mercury removal process.

  6. Evaluation of Lignocellulosic Biomass Degradation by Combining Mid- and Near-Infrared Spectra by the Outer Product and Selecting Discriminant Wavenumbers Using a Genetic Algorithm.

    PubMed

    Rammal, Abbas; Perrin, Eric; Chabbert, Brigitte; Bertrand, Isabelle; Habrant, Anouck; Lecart, Brieuc; Vrabie, Valeriu

    2015-11-01

    Mid-infrared (MIR) and near-infrared (NIR) spectroscopy provide useful information on the molecular composition of biological systems. Because they are sensitive to organic and mineral components, there is a growing interest in these techniques for the development of biomarkers that reflect intrinsic characteristics of plants and their mode of degradation. Due to their complexity and complementary nature, an important challenge is the combining of MIR and NIR information to identify discriminating wavenumbers in each wavenumber region, with the ultimate goal of assessing the biodegradation process of a lignocellulosic biomass at different time scales. This work investigates the potential of using the outer product to combine MIR and NIR spectra to highlight the connections between fundamental molecular vibrations and their combinations and bonds. Because this operation yields high-dimensional spectra, we propose to use a genetic algorithm to select the most discriminant wavenumbers within the degradation process. The results from two lignocellulosic biomasses with different biodegradation kinetics, miscanthus aerial parts and maize roots, confirm that the outer product combination of MIR and NIR spectral information allows a better discrimination of the biodegradation kinetic compared with the simple concatenation of MIR and NIR spectra or with the use of MIR or MIR spectral information separately. We show that the genetic algorithm selects wavenumbers that correspond to principal vibrations of chemical functional groups of compounds that undergo degradation/conversion during the biodegradation of the lignocellulosic biomass.

  7. High-Throughput Screening of Recalcitrance Variations in Lignocellulosic Biomass: Total Lignin, Lignin Monomers, and Enzymatic Sugar Release

    SciTech Connect

    Decker, Stephen R.; Sykes, Robert W.; Turner, Geoffrey B.; Lupoi, Jason S.; Doepkke, Crissa; Tucker, Melvin P.; Schuster, Logan A.; Mazza, Kimberly; Himmel, Michael E.; Davis, Mark F.; Gjersing, Erica

    2015-09-15

    The conversion of lignocellulosic biomass to fuels, chemicals, and other commodities has been explored as one possible pathway toward reductions in the use of non-renewable energy sources. In order to identify which plants, out of a diverse pool, have the desired chemical traits for downstream applications, attributes, such as cellulose and lignin content, or monomeric sugar release following an enzymatic saccharification, must be compared. The experimental and data analysis protocols of the standard methods of analysis can be time-consuming, thereby limiting the number of samples that can be measured. High-throughput (HTP) methods alleviate the shortcomings of the standard methods, and permit the rapid screening of available samples to isolate those possessing the desired traits. This study illustrates the HTP sugar release and pyrolysis-molecular beam mass spectrometry pipelines employed at the National Renewable Energy Lab. These pipelines have enabled the efficient assessment of thousands of plants while decreasing experimental time and costs through reductions in labor and consumables.

  8. Soil-Derived Microbial Consortia Enriched with Different Plant Biomass Reveal Distinct Players Acting in Lignocellulose Degradation.

    PubMed

    de Lima Brossi, Maria Julia; Jiménez, Diego Javier; Cortes-Tolalpa, Larisa; van Elsas, Jan Dirk

    2016-04-01

    Here, we investigated how different plant biomass, and-for one substrate-pH, drive the composition of degrader microbial consortia. We bred such consortia from forest soil, incubated along nine aerobic sequential - batch enrichments with wheat straw (WS1, pH 7.2; WS2, pH 9.0), switchgrass (SG, pH 7.2), and corn stover (CS, pH 7.2) as carbon sources. Lignocellulosic compounds (lignin, cellulose and xylan) were best degraded in treatment SG, followed by CS, WS1 and WS2. In terms of composition, the consortia became relatively stable after transfers 4 to 6, as evidenced by PCR-DGGE profiles obtained from each consortium DNA. The final consortia differed by ~40 % (bacteria) and ~60 % (fungi) across treatments. A 'core' community represented by 5/16 (bacteria) and 3/14 (fungi) bands was discerned, next to a variable part. The composition of the final microbial consortia was strongly driven by the substrate, as taxonomically-diverse consortia appeared in the different substrate treatments, but not in the (WS) different pH one. Biodegradative strains affiliated to Sphingobacterium kitahiroshimense, Raoultella terrigena, Pseudomonas putida, Stenotrophomonas rhizophila (bacteria), Coniochaeta ligniaria and Acremonium sp. (fungi) were recovered in at least three treatments, whereas strains affiliated to Delftia tsuruhatensis, Paenibacillus xylanexedens, Sanguibacter inulus and Comamonas jiangduensis were treatment-specific.

  9. High-throughput Screening of Recalcitrance Variations in Lignocellulosic Biomass: Total Lignin, Lignin Monomers, and Enzymatic Sugar Release

    PubMed Central

    Decker, Stephen R.; Sykes, Robert W.; Turner, Geoffrey B.; Lupoi, Jason S.; Doepkke, Crissa; Tucker, Melvin P.; Schuster, Logan A.; Mazza, Kimberly; Himmel, Michael E.; Davis, Mark F.; Gjersing, Erica

    2015-01-01

    The conversion of lignocellulosic biomass to fuels, chemicals, and other commodities has been explored as one possible pathway toward reductions in the use of non-renewable energy sources. In order to identify which plants, out of a diverse pool, have the desired chemical traits for downstream applications, attributes, such as cellulose and lignin content, or monomeric sugar release following an enzymatic saccharification, must be compared. The experimental and data analysis protocols of the standard methods of analysis can be time-consuming, thereby limiting the number of samples that can be measured. High-throughput (HTP) methods alleviate the shortcomings of the standard methods, and permit the rapid screening of available samples to isolate those possessing the desired traits. This study illustrates the HTP sugar release and pyrolysis-molecular beam mass spectrometry pipelines employed at the National Renewable Energy Lab. These pipelines have enabled the efficient assessment of thousands of plants while decreasing experimental time and costs through reductions in labor and consumables. PMID:26437006

  10. Assessment of hydrothermal pretreatment of various lignocellulosic biomass with CO2 catalyst for enhanced methane and hydrogen production.

    PubMed

    Eskicioglu, Cigdem; Monlau, Florian; Barakat, Abdellatif; Ferrer, Ivet; Kaparaju, Prasad; Trably, Eric; Carrère, Hélène

    2017-09-01

    Hydrothermal pretreatment of five lignocellulosic substrates (i.e. wheat straw, rice straw, biomass sorghum, corn stover and Douglas fir bark) were conducted in the presence of CO2 as a catalyst. To maximize disintegration and conversion into bioenergy (methane and hydrogen), pretreatment temperatures and subsequent pressures varied with a range of 26-175 °C, and 25-102 bars, respectively. Among lignin, cellulose and hemicelluloses, hydrothermal pretreatment caused the highest reduction (23-42%) in hemicelluloses while delignification was limited to only 0-12%. These reductions in structural integrity resulted in 20-30% faster hydrolysis rates during anaerobic digestion for the pretreated substrates of straws, sorghum, and corn stover while Douglas fir bark yielded 172% faster hydrolysis/digestion due to its highly refractory nature in the control. Furans and phenolic compounds formed in the pretreated hydrolyzates were below the inhibitory levels for methane and hydrogen production which had a range of 98-340 ml CH4/g volatile solids (VS) and 5-26 ml H2/g VS, respectively. Results indicated that hydrothermal pretreatment is able to accelerate the rate of biodegradation without generating high levels of inhibitory compounds while showing no discernible effect on ultimate biodegradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Recycling cellulases by pH-triggered adsorption-desorption during the enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Shang, Yaping; Su, Rongxin; Huang, Renliang; Yang, Yang; Qi, Wei; Li, Qiujin; He, Zhimin

    2014-06-01

    Recycling of cellulases is an effective way to reduce the cost of enzymatic hydrolysis for the production of cellulosic ethanol. In this study, we examined the adsorption and desorption behaviors of cellulase at different pH values and temperatures. Furthermore, we developed a promising way to recover both free and bound cellulases by pH-triggered adsorption-desorption. The results show that acidic pH (e.g., pH 4.8) was found to favor adsorption, whereas alkaline pH (e.g., pH 10) and low temperature (4-37 °C) favored desorption. The adsorption of cellulases reached an equilibrium within 60 min at pH 4.8 and 25 °C, leading to approximately 50 % of the added cellulases bound to the substrate. By controlling the pH of eluent (citrate buffer, 25 °C), we were able to increase the desorption efficiency of bound cellulases from 15 % at pH 4.8 to 85 % at pH 10. To recover cellulases after enzymatic hydrolysis, we employed adsorption by fresh substrate and desorption at pH 10 to recover the free cellulases in supernatant and the bound cellulases in residue, respectively. The recycling performance (based on the glucose yield) of this simple strategy could reach near 80 %. Our results provided a simple, low-cost, and effective approach for cellulase recycling during the enzymatic hydrolysis of lignocellulosic biomass.

  12. Kinetic and energy production analysis of pyrolysis of lignocellulosic biomass using a three-parallel Gaussian reaction model.

    PubMed

    Chen, Tianju; Zhang, Jinzhi; Wu, Jinhu

    2016-07-01

    The kinetic and energy productions of pyrolysis of a lignocellulosic biomass were investigated using a three-parallel Gaussian distribution method in this work. The pyrolysis experiment of the pine sawdust was performed using a thermogravimetric-mass spectroscopy (TG-MS) analyzer. A three-parallel Gaussian distributed activation energy model (DAEM)-reaction model was used to describe thermal decomposition behaviors of the three components, hemicellulose, cellulose and lignin. The first, second and third pseudocomponents represent the fractions of hemicellulose, cellulose and lignin, respectively. It was found that the model is capable of predicting the pyrolysis behavior of the pine sawdust. The activation energy distribution peaks for the three pseudo-components were centered at 186.8, 197.5 and 203.9kJmol(-1) for the pine sawdust, respectively. The evolution profiles of H2, CH4, CO, and CO2 were well predicted using the three-parallel Gaussian distribution model. In addition, the chemical composition of bio-oil was also obtained by pyrolysis-gas chromatography/mass spectrometry instrument (Py-GC/MS).

  13. Pyrolysis-GC-MS analysis of the formation and degradation stages of charred residues from lignocellulosic biomass.

    PubMed

    González-Vila, F J; Tinoco, P; Almendros, G; Martin, F

    2001-03-01

    The structural transformations undergone by lignocellulosic biomass (freeze-dried rye grass, Lolium rigidum) subjected to progressive isothermal heating (burning at 350 degrees C under oxidizing conditions for 30, 45, 60, 75, and 90 s) have been monitored by Curie-point pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The pyrograms suggest that even charred residues after severe heating (carbon loss ca. 50%) still contain substantial concentrations of some resistant plant structural components. Several trends were observed when monitoring the relative concentrations of the different groups of pyrolysis compounds released during successive charring stages: (i) the tetrapyrrole moiety of chlorophylls is rapidly destroyed as indicated by the decreasing yields of pyrroles and pyrrolines, whereas the phytol backbone is comparatively more resistant, leading to phytadienes after dehydration and reduction; (ii) the increasing yields of imidazoles from progressively heated samples (maximum at 45 s stage) suggest accumulation of newly formed nitrogen-containing compounds that may survive natural fires; (iii) the lignin backbone shows a relative resistance, the yields of aromatic products pointing to progressive demethoxylation; and, (iv) a selective accumulation of recalcitrant alkyl material occurred, which is interpreted as the result of thermal condensation of hydrocarbons and fatty acids into macromolecular materials in the charred residue. In terms of the intensity of the isothermal heating, the yields of the different classes of alkyl compounds follow the order phytadienes < fatty acids < alkanes < wax esters < sterols.

  14. High-throughput Screening of Recalcitrance Variations in Lignocellulosic Biomass: Total Lignin, Lignin Monomers, and Enzymatic Sugar Release.

    PubMed

    Decker, Stephen R; Sykes, Robert W; Turner, Geoffrey B; Lupoi, Jason S; Doepkke, Crissa; Tucker, Melvin P; Schuster, Logan A; Mazza, Kimberly; Himmel, Michael E; Davis, Mark F; Gjersing, Erica

    2015-09-15

    The conversion of lignocellulosic biomass to fuels, chemicals, and other commodities has been explored as one possible pathway toward reductions in the use of non-renewable energy sources. In order to identify which plants, out of a diverse pool, have the desired chemical traits for downstream applications, attributes, such as cellulose and lignin content, or monomeric sugar release following an enzymatic saccharification, must be compared. The experimental and data analysis protocols of the standard methods of analysis can be time-consuming, thereby limiting the number of samples that can be measured. High-throughput (HTP) methods alleviate the shortcomings of the standard methods, and permit the rapid screening of available samples to isolate those possessing the desired traits. This study illustrates the HTP sugar release and pyrolysis-molecular beam mass spectrometry pipelines employed at the National Renewable Energy Lab. These pipelines have enabled the efficient assessment of thousands of plants while decreasing experimental time and costs through reductions in labor and consumables.

  15. Evaluation of High Throughput Screening Methods in Picking up Differences between Cultivars of Lignocellulosic Biomass for Ethanol Production

    SciTech Connect

    Lindedam, Jane; Bruun, Sander; Jorgensen, Henning; Decker, Stephen R.; Turner, Geoffrey B.; DeMartini, Jaclyn D.; Wyman, Charles E.; Felby, Claus

    2014-07-01

    Here, we present a unique evaluation of three advanced high throughput pretreatment and enzymatic hydrolysis systems (HTPH-systems) for screening of lignocellulosic biomass for enzymatic saccharification. Straw from 20 cultivars of winter wheat from two sites in Denmark was hydrothermally pretreated and enzymatically processed in each of the separately engineered HTPH-systems at 1) University of California, Riverside, 2) National Renewable Energy Laboratory (NREL), Colorado, and 3) University of Copenhagen (CPH). All three systems were able to detect significant differences between the cultivars in the release of fermentable sugars, with average cellulose conversions of 57%, 64%, and 71% from Riverside, NREL and CPH, respectively. We found the best correlation of glucose yields between the Riverside and NREL systems (R2 = 0.2139), and the best correlation for xylose yields was found between Riverside and CPH (R2 = 0.4269). The three systems identified Flair as the highest yielding cultivar and Dinosor, Glasgow, and Robigus as low yielding cultivars. Despite different conditions in the three HTPH-systems, the approach of microscale screening for phenotypically less recalcitrant feedstock seems sufficiently robust to be used as a generic analytical platform.

  16. A feasibility study on the multistage process for the oxalic acid pretreatment of a lignocellulosic biomass using electrodialysis.

    PubMed

    Lee, Hong-Joo; Ahn, Sung Ju; Seo, Young-Jun; Lee, Jae-Won

    2013-02-01

    The present study investigated the feasibility of the recovery and reuse oxalic acid in a multistage process for the pretreatment of a lignocellulosic biomass. Electrodialysis (ED), an electrochemical process using ion exchange membranes, was used to recover and reuse oxalic acid in the multistage process. The ED optimal condition for recover oxalic acid was potential of 10V and pH 2.2 in synthetic solutions. The recovery efficiency of oxalic acid from hydrolysates reached 100% at potential of 10V. The power consumption to treat 1mol of oxalic acid was estimated to be 41.0wh. At the same time, ethanol production increased up to 19g/L in the ED-treated hydrolysate, corresponding to ethanol productivity of 0.27g/L/h. It was clearly shown that bioethanol fermentation efficiency increased using the ED process, due to a small loss of fermentable sugar and a significantly high removal of inhibitory chemicals. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Use of mechanical refining to improve the production of low-cost sugars from lignocellulosic biomass.

    PubMed

    Park, Junyeong; Jones, Brandon; Koo, Bonwook; Chen, Xiaowen; Tucker, Melvin; Yu, Ju-Hyun; Pschorn, Thomas; Venditti, Richard; Park, Sunkyu

    2016-01-01

    Mechanical refining is widely used in the pulp and paper industry to enhance the end-use properties of products by creating external fibrillation and internal delamination. This technology can be directly applied to biochemical conversion processes. By implementing mechanical refining technology, biomass recalcitrance to enzyme hydrolysis can be overcome and carbohydrate conversion can be enhanced with commercially attractive levels of enzymes. In addition, chemical and thermal pretreatment severity can be reduced to achieve the same level of carbohydrate conversion, which reduces pretreatment cost and results in lower concentrations of inhibitors. Refining is versatile and a commercially proven technology that can be operated at process flows of ∼ 1500 dry tons per day of biomass. This paper reviews the utilization of mechanical refining in the pulp and paper industry and summarizes the recent development in applications for biochemical conversion, which potentially make an overall biorefinery process more economically viable.

  18. Study on pyrolysis characteristics of lignocellulosic biomass impregnated with ammonia source.

    PubMed

    Li, Kai; Zhu, Changpeng; Zhang, Liqiang; Zhu, Xifeng

    2016-06-01

    The current study presents the pyrolysis characteristics of rice husk impregnated with different kinds of ammonia source (ammonium acetate, urea, ammonium sulfate and ammonium dihydrogen phosphate) in a fixed bed reactor. The introduction of ammonia source in pyrolysis process achieved the conversation from carbonyl compounds to nitrogenous heterocyclic compounds. The liquid product of urea-impregnated biomass has higher content of nitrogenous heterocyclic compounds (8.35%) and phenols (30.4%). For ammonium sulfate and ammonium dihydrogen phosphate-impregnated biomass, the quantity of compounds in liquid products reduces remarkably, and the gas products are rich in CO and H2. All the solid products of pyrolysis have great potential application in biochar-based fertilizer and activated carbon for their high N content.

  19. Alcohol dehydrogenases from Scheffersomyces stipitis involved in the detoxification of aldehyde inhibitors derived from lignocellulosic biomass conversion.

    PubMed

    Ma, Menggen; Wang, Xu; Zhang, Xiaoping; Zhao, Xianxian

    2013-09-01

    Aldehyde inhibitors such as furfural and 5-hydroxymethylfurfural (HMF) are generated from biomass pretreatment. Scheffersomyces stipitis is able to reduce furfural and HMF to less toxic furanmethanol and furan-2,5-dimethanol; however, the enzymes involved in the reductive reaction still remain unknown. In this study, transcription responses of two known and five putative alcohol dehydrogenase genes from S. stipitis were analyzed under furfural and HMF stress conditions. All the seven alcohol dehydrogenase genes were also cloned and overexpressed for their activity analyses. Our results indicate that transcriptions of SsADH4 and SsADH6 were highly induced under furfural and HMF stress conditions, and the proteins encoded by them exhibited NADH- and/or NADPH-dependent activities for furfural and HMF reduction, respectively. For furfural reduction, NADH-dependent activity was also observed in SsAdh1p and NAD(P)H-dependent activities were also observed in SsAdh5p and SsAdh7p. For HMF reduction, NADPH-dependent activities were also observed in SsAdh5p and SsAdh7p. SsAdh4p displayed the highest NADPH-dependent specific activity and catalytic efficiency for reduction of both furfural and HMF among the seven alcohol dehydrogenases. Enzyme activities of all SsADH proteins were more stable under acidic condition. For most SsADH proteins, the optimum temperature for enzyme activities was 30 °C and more than 50 % enzyme activities remained at 60 °C. Reduction activities of formaldehyde, acetaldehyde, isovaleraldehyde, benzaldehyde, and phenylacetaldehyde were also observed in some SsADH proteins. Our results indicate that multiple alcohol dehydrogenases in S. stipitis are involved in the detoxification of aldehyde inhibitors derived from lignocellulosic biomass conversion.

  20. Characterization of oxalic acid pretreatment on lignocellulosic biomass using oxalic acid recovered by electrodialysis.

    PubMed

    Lee, Hong-Joo; Seo, Young-Jun; Lee, Jae-Won

    2013-04-01

    The properties of pretreated biomass and hydrolysate obtained by oxalic acid pretreatment using oxalic acid recovered through electrodialysis (ED) were investigated. Most of the oxalic acid was recovered and some of the fermentation inhibitors were removed by ED. For the original hydrolysate, the ethanol production was very low and fermentable sugars were not completely consumed by Pichia stipitis during fermentation. Ethanol yield was less than 0.12 g/g in all stage. For the ED-treated hydrolysate, ethanol production was increased by up to two times in all stages compared to the original hydrolysate. The highest ethanol production was 19.38 g/l after 72 h which correspond to the ethanol yield of 0.33 g/g. Enzymatic conversion of the cellulose to glucose for all the pretreated biomass was in the range of 76.03 and 77.63%. The hydrolysis rate on each pretreated biomass was not significantly changed when oxalic acid recovered by ED was used for pretreatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Further Improvement of the Robust Recombinant Saccharomyces Yeast for the Conversion of Lignocellulosic Biomass to Ethanol

    SciTech Connect

    Ho, Nancy, W. Y.; Adamec, Jiri; Mosier, Nathan, S.; Sedlak, Miroslav

    2011-04-07

    Since 1980, the PI's laboratory at Purdue University has been at the forefront in developing recombinant Saccharomyces yeast for cellulosic ethanol production. Their innovation enabled them to successfully develop the recombinant Saccharomyces yeast strain 424A(LNH-ST) that has been validated by scientists in industry, universities, and National Laboratories. Strain 424A(LNH-ST) has also been used by a company to produce cellulosic ethanol since 2004. Nevertheless, this strain still needs improvement, particularly to achieve high ethanol titer when cellulosic biomass hydrolysates are used for ethanol production. In this project, we were able to carry out a total genetic overhaul of our yeast by carrying out nine different tasks to improve our 424A(LNH-ST) strain. Through these tasks we enabled the yeast to co-ferment arabinose together with other four sugars generally present in all cellulosic biomass. Thus 424A(LNH-ST) can now ferment all five sugars, glucose, xylose, mannose, galactose and arabinose present in any cellulosic biomass. We also successfully used adaptation techniques and direct genetic improvements to develop improved 424A(LNH-ST) strains that are more resistant to acetic acid or ethanol. These are the most significant inhibitors of those commonly present in cellulosic hydrolysates that prevent 424A(LNH-ST) from producing high concentrations of cellulosic ethanol. The acetic acid resistant strain has 89% better xylose utilization in the presence of acetic acid and 25% better overall ethanol yield. The ethanol resistant strain has 250% better ethanol volumetric productivity. The three tasks for improving the main metabolic pathways have all been successfully completed but the impact of these improvements was less dramatic. This demonstrates our yeast already has effective metabolic systems for co-fermenting cellulosic sugars. However, our attempt to improve the yeast to transport xylose and arabinose more efficiently had only limited success. Thus

  2. Further Improvement of the Robust Recombinant Saccharomyces Yeast for the Conversion of Lignocellulosic Biomass to Ethanol

    SciTech Connect

    Ho, Nancy W. Y.; Adamec, Jiri; Mosier, Nathan, S.; Sedlak, Miroslav

    2011-04-09

    Since 1980, the PI’s laboratory at Purdue University has been at the forefront in developing recombinant Saccharomyces yeast for cellulosic ethanol production. Their innovation enabled them to successfully develop the recombinant Saccharomyces yeast strain 424A(LNH-ST) that has been validated by scientists in industry, universities, and National Laboratories. Strain 424A(LNH-ST) has also been used by a company to produce cellulosic ethanol since 2004. Nevertheless, this strain still needs improvement, particularly to achieve high ethanol titer when cellulosic biomass hydrolysates are used for ethanol production. In this project, we were able to carry out a total genetic overhaul of our yeast by carrying out nine different tasks to improve our 424A(LNH-ST) strain. Through these tasks we enabled the yeast to co-ferment arabinose together with other four sugars generally present in all cellulosic biomass. Thus 424A(LNH-ST) can now ferment all five sugars, glucose, xylose, mannose, galactose and arabinose present in any cellulosic biomass. We also successfully used adaptation techniques and direct genetic improvements to develop improved 424A(LNH-ST) strains that are more resistant to acetic acid or ethanol. These are the most significant inhibitors of those commonly present in cellulosic hydrolysates that prevent 424A(LNH-ST) from producing high concentrations of cellulosic ethanol. The acetic acid resistant strain has 89% better xylose utilization in the presence of acetic acid and 25% better overall ethanol yield. The ethanol resistant strain has 250% better ethanol volumetric productivity. The three tasks for improving the main metabolic pathways have all been successfully completed but the impact of these improvements was less dramatic. This demonstrates our yeast already has effective metabolic systems for co-fermenting cellulosic sugars. However, our attempt to improve the yeast to transport xylose and arabinose more efficiently had only limited success. Thus

  3. Enzymatic hydrolysis and characterization of waste lignocellulosic biomass produced after dye bioremediation under solid state fermentation.

    PubMed

    Waghmare, Pankajkumar R; Kadam, Avinash A; Saratale, Ganesh D; Govindwar, Sanjay P

    2014-09-01

    Sugarcane bagasse (SCB) adsorbes 60% Reactive Blue172 (RB172). Providensia staurti EbtSPG able to decolorize SCB adsorbed RB172 up to 99% under solid state fermentation (SSF). The enzymatic saccharification efficiency of waste biomass after bioremediation of RB172 process (ddSCB) has been evaluated. The cellulolyitc crude enzyme produced by Phanerochaete chrysosporium used for enzymatic hydrolysis of native SCB and ddSCB which produces 0.08 and 0.3 g/L of reducing sugars respectively after 48 h of incubation. The production of hexose and pentose sugars during hydrolysis was confirmed by HPTLC. The effect of enzymatic hydrolysis on SCB and ddSCB has been evaluated by FTIR, XRD and SEM analysis. Thus, during dye biodegradation under SSF causes biological pretreatment of SCB which significantly enhanced its enzymatic saccharification. Adsorption of dye on SCB, its bioremediation under SSF produces wastes biomass and which further utilized for enzymatic saccharification for biofuel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Engineering a thermoregulated intein-modified xylanase into maize for consolidated lignocellulosic biomass processing.

    PubMed

    Shen, Binzhang; Sun, Xueguang; Zuo, Xiao; Shilling, Taran; Apgar, James; Ross, Mary; Bougri, Oleg; Samoylov, Vladimir; Parker, Matthew; Hancock, Elaina; Lucero, Hector; Gray, Benjamin; Ekborg, Nathan A; Zhang, Dongcheng; Johnson, Jeremy C Schley; Lazar, Gabor; Raab, R Michael

    2012-11-01

    Plant cellulosic biomass is an abundant, low-cost feedstock for producing biofuels and chemicals. Expressing cell wall-degrading (CWD) enzymes (e.g. xylanases) in plant feedstocks could reduce the amount of enzymes required for feedstock pretreatment and hydrolysis during bioprocessing to release soluble sugars. However, in planta expression of xylanases can reduce biomass yield and plant fertility. To overcome this problem, we engineered a thermostable xylanase (XynB) with a thermostable self-splicing bacterial intein to control the xylanase activity. Intein-modified XynB (iXynB) variants were selected that have <10% wild-type enzymatic activity but recover >60% enzymatic activity upon intein self-splicing at temperatures >59 °C. Greenhouse-grown xynB maize expressing XynB has shriveled seeds and low fertility, but ixynB maize had normal seeds and fertility. Processing dried ixynB maize stover by temperature-regulated xylanase activation and hydrolysis in a cocktail of commercial CWD enzymes produced >90% theoretical glucose and >63% theoretical xylose yields.

  5. Role of Pretreatment and Conditioning Processes on Toxicity of Lignocellulosic Biomass Hydrolysates

    SciTech Connect

    Pienkos, P. T.; Zhang, M.

    2009-01-01

    The Department of Energy's Office of the Biomass Program has set goals of making ethanol cost competitive by 2012 and replacing 30% of 2004 transportation supply with biofuels by 2030. Both goals require improvements in conversions of cellulosic biomass to sugars as well as improvements in fermentation rates and yields. Current best pretreatment processes are reasonably efficient at making the cellulose/hemicellulose/lignin matrix amenable to enzymatic hydrolysis and fermentation, but they release a number of toxic compounds into the hydrolysate which inhibit the growth and ethanol productivity of fermentation organisms. Conditioning methods designed to reduce the toxicity of hydrolysates are effective, but add to process costs and tend to reduce sugar yields, thus adding significantly to the final cost of production. Reducing the cost of cellulosic ethanol production will likely require enhanced understanding of the source and mode of action of hydrolysate toxic compounds, the means by which some organisms resist the actions of these compounds, and the methodology and mechanisms for conditioning hydrolysate to reduce toxicity. This review will provide an update on the state of knowledge in these areas and can provide insights useful for the crafting of hypotheses for improvements in pretreatment, conditioning, and fermentation organisms.

  6. Influence of pretreatment with Fenton's reagent on biogas production and methane yield from lignocellulosic biomass.

    PubMed

    Michalska, Karina; Miazek, Krystian; Krzystek, Liliana; Ledakowicz, Stanisław

    2012-09-01

    Biomass from Miscanthus giganteus, Sida hermaphrodita and Sorghum Moensch was treated with Fenton's reagent for 2 hours under optimal conditions (pH=3, mass ratio of [Fe(2+)]:[H(2)O(2)] equals 1:25 for Miscanthus and Sorghum and 1:15 for Sida). The degrees of delignification were 30.3%, 62.3% and 48.1% for the three plant species, respectively. The volatile fatty acids concentration after chemical pretreatment was high enough for production of biogas with a high methane content. Combined chemical oxidation and enzymatic hydrolysis with cellulase and cellobiase led to glucose contents of above 4 g/L. Among the tested plants, the highest biogas production (25.2 Ndm(3)/kg TS fed) with a 75% methane content was obtained with Sorghum Moensch. The results of the three-step process of biomass degradation show the necessity of applying a chemical pretreatment such as oxidation with Fenton's reagent. Moreover, the coagulation of residual Fe(3+) ions is not required for high biogas production.

  7. Improvement of radio frequency (RF) heating-assisted alkaline pretreatment on four categories of lignocellulosic biomass.

    PubMed

    Wang, Xiaofei; Taylor, Steven; Wang, Yifen

    2016-10-01

    Pretreatment plays an important role in making the cellulose accessible for enzyme hydrolysis and subsequent conversion because it destroys more or less resistance and recalcitrance of biomass. Radio frequency (RF)-assisted dielectric heating was utilized in the alkaline pretreatment on agricultural residues (corn stover), herbaceous crops (switchgrass), hardwood (sweetgum) and softwood (loblolly pine). Pretreatment was performed at 90 °C with either RF or traditional water bath (WB) heating for 1 h after overnight soaking in NaOH solution (0.2 g NaOH/g Biomass). Pretreated materials were characterized by chemical compositional analysis, enzyme hydrolysis, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The glucan yields of RF-heated four categories of hydrolysates were 89.6, 72.6, 21.7, and 9.9 %. Interestingly, RF heating raised glucan yield on switchgrass and sweetgum but not on corn stover or loblolly pine. The SEM images and FTIR spectra agreed with results of composition analysis and hydrolysis. GC-MS detected some compounds only from RF-heated switchgrass. These compounds were found by other researchers only in high-temperature (150-600 °C) and high-pressure pyrolysis processes.

  8. Mineral-vegetal co-milling: An effective process to improve lignocellulosic biomass fine milling and to increase interweaving between mixed particles.

    PubMed

    Motte, J-C; Delenne, J-Y; Rouau, X; Mayer-Laigle, C

    2015-09-01

    Fine-milling is a crucial objective for lignocellulosic biomass valorization. Co-milling appears to be a promising technique to improve its efficiency. However, the mechanisms occurring while co-milling remain poorly understood. In this study, an experimental work was performed to produce co-milled powders from both lignocellulosic (wheat, straw or pine sawdust) and mineral materials (limestone, quartzite or tile) with very contrasted physicochemical properties. The main consequences of co-milling were studied for both materials. A two-component mixing law for the prediction of the blend properties was proposed (particle sizes and true densities) to highlight the gain of this single processing step compared to separate milling and mixing. The predicted values were compared with experimental data for co-milled powders at 7 biomass contents from 0% to 100%. In all cases, co-milling leads to a reduction in particle size of lignocellulosic materials and create strong interweaving with mineral particles. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  9. Improved enzymatic hydrolysis of lignocellulosic biomass through pretreatment with plasma electrolysis.

    PubMed

    Gao, Jing; Chen, Li; Zhang, Jian; Yan, Zongcheng

    2014-11-01

    A comprehensive research on plasma electrolysis as pretreatment method for water hyacinth (WH) was performed based on lignin content, crystalline structure, surface property, and enzymatic hydrolysis. A large number of active particles, such as HO and H2O2, generated by plasma electrolysis could decompose the lignin of the biomass samples and reduce the crystalline index. An efficient pretreatment process made use of WH pretreated at a load of 48 wt% (0.15-0.18 mm) in FeCl3 solution for 30 min at 450 V. After the pretreatment, the sugar yield of WH was increased by 126.5% as compared with unpretreated samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Production of phenols and biofuels by catalytic microwave pyrolysis of lignocellulosic biomass.

    PubMed

    Bu, Quan; Lei, Hanwu; Ren, Shoujie; Wang, Lu; Zhang, Qin; Tang, Juming; Ruan, Roger

    2012-03-01

    Catalytic microwave pyrolysis of biomass using activated carbon (AC) was investigated to determine the effects of pyrolytic conditions on the yields of phenol and phenolics. Bio-oils with high concentrations of phenol (38.9%) and phenolics (66.9%) were obtained. These levels were higher than those obtained by pyrolysis without AC addition and were closely related to the decomposition of lignin. A high concentration of esters (42.2% in the upgraded bio-oil) was obtained in the presence of Zn powder as catalyst and formic acid/ethanol as reaction medium. Most of the esters identified by GC-MS were long chain fatty acid esters. The high content of phenols and esters obtained in this study can be used as partial replacement of petroleum fuels after separation of oxygenates or as feedstock for organic syntheses in the chemical industry after purification.

  11. Efficient catalytic system for the direct transformation of lignocellulosic biomass to furfural and 5-hydroxymethylfurfural.

    PubMed

    Zhang, Luxin; Xi, Guoyun; Zhang, Jiaxin; Yu, Hongbing; Wang, Xiaochang

    2017-01-01

    A feasible approach was developed for the co-production of 5-hydroxymethylfurfural (5-HMF) and furfural from corncob via a new porous polytriphenylamine-SO3H (SPTPA) solid acid catalyst in lactone solvents. XRD, SEM, XPS, N2 adsorption-desorption, elemental analysis, TG-DTA, acid-base titration and FTIR spectroscopy techniques were used to characterize the catalyst. This study demonstrates and optimizes the catalytic performance of SPTPA and solvent selection. SPTPA was found to exhibit superior catalytic ability in γ-valerolactone (GVL). Under the optimum reaction conditions, simultaneously encouraging yields of furfural (73.9%) and 5-HMF (32.3%) were achieved at 448K. The main advantages of this process include reasonable yields of both 5-HMF and furfural in the same reaction system, practical simplicity for the raw biomass utilization, and the use of a safe and environmentally benign solvent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Optimization of levulinic acid from lignocellulosic biomass using a new hybrid catalyst.

    PubMed

    Ya'aini, Nazlina; Amin, Nor Aishah Saidina; Asmadi, Mohd

    2012-07-01

    Conversion of glucose, empty fruit bunch (efb) and kenaf to levulinic acid over a new hybrid catalyst has been investigated in this study. The characterization and catalytic performance results revealed that the physico-chemical properties of the new hybrid catalyst comprised of chromium chloride and HY zeolite increased the levulinic acid production from glucose compared to the parent catalysts. Optimization of the glucose conversion process using two level full factorial designs (2(3)) with two center points reported 55.2% of levulinic acid yield at 145.2 °C, 146.7 min and 12.0% of reaction temperature, reaction time and catalyst loading, respectively. Subsequently, the potential of efb and kenaf for producing levulinic acid at the optimum conditions was established after 53.2% and 66.1% of efficiencies were reported. The observation suggests that the hybrid catalyst has a potential to be used in biomass conversion to levulinic acid.

  13. Supported molybdenum oxides as effective catalysts for the catalytic fast pyrolysis of lignocellulosic biomass

    SciTech Connect

    Murugappan, Karthick; Mukarakate, Calvin; Budhi, Sridhar; Shetty, Manish; Nimlos, Mark R.; Román-Leshkov, Yuriy

    2016-07-12

    The catalytic fast pyrolysis (CFP) of pine was investigated over 10 wt% MoO3/TiO2 and MoO3/ZrO2 at 500 °C and H2 pressures ≤ 0.75 bar. The product distributions were monitored in real time using a molecular beam mass spectrometer (MBMS). Both supported MoO3 catalysts show different levels of deoxygenation based on the cumulative biomass to MoO3 mass ratio exposed to the catalytic bed. For biomass to MoO3 mass ratios <1.5, predominantly olefinic and aromatic hydrocarbons are produced with no detectable oxygen-containing species. For ratios ≥ 1.5, partially deoxygenated species comprised of furans and phenols are observed, with a concomitant decrease of olefinic and aromatic hydrocarbons. For ratios ≥ 5, primary pyrolysis vapours break through the bed, indicating the onset of catalyst deactivation. Product quantification with a tandem micropyrolyzer-GCMS setup shows that fresh supported MoO3 catalysts convert ca. 27 mol% of the original carbon into hydrocarbons comprised predominantly of aromatics (7 C%), olefins (18 C%) and paraffins (2 C%), comparable to the total hydrocarbon yield obtained with HZSM-5 operated under similar reaction conditions. In conclusion, post-reaction XPS analysis on supported MoO3/ZrO2 and MoO3/TiO2 catalysts reveal that ca. 50% of Mo surface species exist in their partially reduced forms (i.e., Mo5+ and Mo3+), and that catalyst deactivation is likely associated to coking.

  14. Supported molybdenum oxides as effective catalysts for the catalytic fast pyrolysis of lignocellulosic biomass

    DOE PAGES

    Murugappan, Karthick; Mukarakate, Calvin; Budhi, Sridhar; ...

    2016-07-12

    The catalytic fast pyrolysis (CFP) of pine was investigated over 10 wt% MoO3/TiO2 and MoO3/ZrO2 at 500 °C and H2 pressures ≤ 0.75 bar. The product distributions were monitored in real time using a molecular beam mass spectrometer (MBMS). Both supported MoO3 catalysts show different levels of deoxygenation based on the cumulative biomass to MoO3 mass ratio exposed to the catalytic bed. For biomass to MoO3 mass ratios <1.5, predominantly olefinic and aromatic hydrocarbons are produced with no detectable oxygen-containing species. For ratios ≥ 1.5, partially deoxygenated species comprised of furans and phenols are observed, with a concomitant decrease ofmore » olefinic and aromatic hydrocarbons. For ratios ≥ 5, primary pyrolysis vapours break through the bed, indicating the onset of catalyst deactivation. Product quantification with a tandem micropyrolyzer-GCMS setup shows that fresh supported MoO3 catalysts convert ca. 27 mol% of the original carbon into hydrocarbons comprised predominantly of aromatics (7 C%), olefins (18 C%) and paraffins (2 C%), comparable to the total hydrocarbon yield obtained with HZSM-5 operated under similar reaction conditions. In conclusion, post-reaction XPS analysis on supported MoO3/ZrO2 and MoO3/TiO2 catalysts reveal that ca. 50% of Mo surface species exist in their partially reduced forms (i.e., Mo5+ and Mo3+), and that catalyst deactivation is likely associated to coking.« less

  15. Supported molybdenum oxides as effective catalysts for the catalytic fast pyrolysis of lignocellulosic biomass

    SciTech Connect

    Murugappan, Karthick; Mukarakate, Calvin; Budhi, Sridhar; Shetty, Manish; Nimlos, Mark R.; Román-Leshkov, Yuriy

    2016-01-01

    The catalytic fast pyrolysis (CFP) of pine was investigated over 10 wt% MoO3/TiO2 and MoO3/ZrO2 at 500 degrees C and H2 pressures =0.75 bar. The product distributions were monitored in real time using a molecular beam mass spectrometer (MBMS). Both supported MoO3 catalysts show different levels of deoxygenation based on the cumulative biomass to MoO3 mass ratio exposed to the catalytic bed. For biomass to MoO3 mass ratios <1.5, predominantly olefinic and aromatic hydrocarbons are produced with no detectable oxygen-containing species. For ratios =1.5, partially deoxygenated species comprised of furans and phenols are observed, with a concomitant decrease of olefinic and aromatic hydrocarbons. For ratios =5, primary pyrolysis vapours break through the bed, indicating the onset of catalyst deactivation. Product quantification with a tandem micropyrolyzer-GCMS setup shows that fresh supported MoO3 catalysts convert ca. 27 mol% of the original carbon into hydrocarbons comprised predominantly of aromatics (7 C%), olefins (18 C%) and paraffins (2 C%), comparable to the total hydrocarbon yield obtained with HZSM-5 operated under similar reaction conditions. Post-reaction XPS analysis on supported MoO3/ZrO2 and MoO3/TiO2 catalysts reveal that ca. 50% of Mo surface species exist in their partially reduced forms (i.e., Mo5+ and Mo3+), and that catalyst deactivation is likely associated to coking.

  16. Evaluating the utility of hydrothermolysis pretreatment approaches in enhancing lignocellulosic biomass degradation by the anaerobic fungus Orpinomyces sp. strain C1A.

    PubMed

    Liggenstoffer, Audra S; Youssef, Noha H; Wilkins, Mark R; Elshahed, Mostafa S

    2014-09-01

    Members of the anaerobic fungi (Phylum Neocallimastigomycota) are efficient biomass degraders and represent promising agents for fuel and chemical production from lignocellulosic biomass. Pretreatment of lignocellulosic biomass is considered an unavoidable first step in enzyme-based saccharification schemes, but its necessity in any proposed anaerobic fungi-based schemes is still unclear. Here, we evaluated the effect of hydrothermal pretreatments on the extent of corn stover and switchgrass degradation by an anaerobic fungal isolate, Orpinomyces sp. strain C1A. Using a factorial experimental design, we evaluated the effect of three different temperatures (180, 190, and 200°C) and three hold times (5, 10, and 15min). Pretreated corn stover and switchgrass were more amenable to degradation by strain C1A when compared to untreated biomass, as evident by the higher proportion of plant biomass degraded compared to untreated controls. However, when factoring in the proportion of biomass lost during the pretreatment process (ranging between 25.78 and 58.92% in corn stover and 28.34 and 38.22% in switchgrass), hydrothermolysis provided negligible or negative improvements to the extent of corn stover and switchgrass degradation by strain C1A. Product analysis demonstrated a shift towards higher ethanol and lactate production and lower acetate production associated with increase in pretreatment severity, especially in switchgrass incubations. The results are in stark contrast to the requirement of pretreatment in enzyme-based schemes for biomass saccharification, and their implications on the potential utility of anaerobic fungi in biofuel and biochemical production are discussed.

  17. Biochemical conversions of lignocellulosic biomass for sustainable fuel-ethanol production in the upper Midwest

    NASA Astrophysics Data System (ADS)

    Brodeur-Campbell, Michael J.

    Biofuels are an increasingly important component of worldwide energy supply. This research aims to understand the pathways and impacts of biofuels production, and to improve these processes to make them more efficient. In Chapter 2, a life cycle assessment (LCA) is presented for cellulosic ethanol production from five potential feedstocks of regional importance to the upper Midwest — hybrid poplar, hybrid willow, switchgrass, diverse prairie grasses, and logging residues — according to the requirements of Renewable Fuel Standard (RFS). Direct land use change emissions are included for the conversion of abandoned agricultural land to feedstock production, and computer models of the conversion process are used in order to determine the effect of varying biomass composition on overall life cycle impacts. All scenarios analyzed here result in greater than 60% reduction in greenhouse gas emissions relative to petroleum gasoline. Land use change effects were found to contribute significantly to the overall emissions for the first 20 years after plantation establishment. Chapter 3 is an investigation of the effects of biomass mixtures on overall sugar recovery from the combined processes of dilute acid pretreatment and enzymatic hydrolysis. Biomass mixtures studied were aspen, a hardwood species well suited to biochemical processing; balsam, a high-lignin softwood species, and switchgrass, an herbaceous energy crop with high ash content. A matrix of three different dilute acid pretreatment severities and three different enzyme loading levels was used to characterize interactions between pretreatment and enzymatic hydrolysis. Maximum glucose yield for any species was 70% of theoretical for switchgrass, and maximum xylose yield was 99.7% of theoretical for aspen. Supplemental β-glucosidase increased glucose yield from enzymatic hydrolysis by an average of 15%, and total sugar recoveries for mixtures could be predicted to within 4% by linear interpolation of the pure

  18. Comparative biochemical analysis after steam pretreatment of lignocellulosic agricultural waste biomass from Williams Cavendish banana plant (Triploid Musa AAA group).

    PubMed

    Kamdem, Irénée; Jacquet, Nicolas; Tiappi, Florian Mathias; Hiligsmann, Serge; Vanderghem, Caroline; Richel, Aurore; Jacques, Philippe; Thonart, Philippe

    2015-11-01

    The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on six combined morphological parts of Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82 ± 3.51 and 49.78 ± 1.39%w/w WCLB dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56 ± 1.33%w/w DM) and SFSC180 (44.47 ± 0.00%w/w DM), while the lowest was found in unpretreated WCLB (22.70 ± 0.71%w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2%w/w of the LF DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210 °C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerization, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors, such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210, were the highest (41 and 21 µg ml(-1), respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments. © The Author(s) 2015.

  19. Conversion of lignocellulosic biomass to green fuel oil over sodium based catalysts.

    PubMed

    Nguyen, T S; Zabeti, M; Lefferts, L; Brem, G; Seshan, K

    2013-08-01

    Upgrading of biomass pyrolysis vapors over 20 wt.% Na2CO3/γ-Al2O3 catalyst was studied in a lab-scale fix-bed reactor at 500°C. Characterization of the catalyst using SEM and XRD has shown that sodium carbonate is well-dispersed on the support γ-Al2O3. TGA and (23)Na MAS NMR suggested the formation of new hydrated sodium phase, which is likely responsible for the high activity of the catalyst. Catalytic oil has much lower oxygen content (12.3 wt.%) compared to non-catalytic oil (42.1 wt.%). This comes together with a tremendous increase in the energy density (37 compared to 19 MJ kg(-1)). Decarboxylation of carboxylic acids was favoured on the catalyst, resulting to an oil almost neutral (TAN=3.8mg KOH/g oil and pH=6.5). However, the mentioned decarboxylation resulted in the formation of carbonyls, which correlates to low stability of the oil. Catalytic pyrolysis results in a bio-oil which resembles a fossil fuel oil in its properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

    PubMed

    Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

    2011-03-01

    Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (<10% conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

  1. Analysis of the lignocellulosic components of biomass residues for biorefinery opportunities.

    PubMed

    Rambo, M K D; Schmidt, F L; Ferreira, M M C

    2015-11-01

    The present study aims to identify the renewable resources available in Brazil such as açai seed, coconut husks, coffee husks, rice husks, eucalyptus sawdust, grass, soy peel, bamboo, banana stems and banana stalks. To identify such renewable energy sources, samples were examined for their physical and chemical characteristics using X-ray diffraction (XRD), proximate and ultimate analyses, thermogravimetric analysis (TGA), calorific value determination, near-infrared (NIR) spectroscopy, UV spectroscopy, high-pH anion-exchange chromatography (HPAEC-PAD) and accelerated solvent extraction (ASE). Among the biomasses, açai and coffee exhibited higher total sugar content, 67.70% and 62.55%, respectively. Sawdust exhibited low ash, along with the highest calorific value and lignin content. The highest glucose contents were observed in bamboo (44.65%) and sawdust (38.80%). The maximum yield for the bioproducts levulinic acid (LA), formic acid (FA) and furfural were estimated; açai exhibited the highest yield of LA and FA, while coffee exhibited the best furfural yield. All of these properties indicate that the residues are potential candidates for bioenergy production.

  2. Evaluation of chlorine dioxide as a supplementary pretreatment reagent for lignocellulosic biomass.

    PubMed

    Acharjee, Tapas C; Jiang, Zhihua; Haynes, Robert Daniel; Lee, Yoon Y

    2017-08-10

    Chlorine dioxide (ClO2) is a bleaching reagent used in paper industry. Two different types of pretreatment methods were investigated incorporating ClO2 as a secondary reagent: (a) alkaline followed by ClO2 treatment; (b) dilute-sulfuric acid followed ClO2 treatment. In these methods, ClO2 treatment has shown little effect on delignification. Scheme-a has shown a significant improvement in enzymatic digestibility of glucan far above that treated by ammonia alone. On the contrary, dilute-acid followed by ClO2 treatment has shown negative effect on the enzymatic hydrolysis. The main factors affecting the enzymatic hydrolysis are the changes of the chemical structure of lignin and its distribution on the biomass surface. ClO2 treatment significantly increases the carboxylic acid content and reduces phenolic groups of lignin, affecting hydrophobicity of lignin and the H-bond induced association between the enzyme and lignin. This collectively led to reduction of unproductive binding of enzyme with lignin, consequently increasing the digestibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Ionic liquid pretreatment to increase succinic acid production from lignocellulosic biomass.

    PubMed

    Wang, Caixia; Yan, Daojiang; Li, Qiang; Sun, Wei; Xing, Jianmin

    2014-11-01

    In this study, pinewood and corn stover pretreated with the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AmimCl) were used as a feedstock for succinic acid production. Results reveal that 5% (v/v) AmimCl inhibited bacterial growth, whereas 0.01% (v/v) AmimCl inhibited succinic acid production. AmimCl was effective in extracting cellulose from pinewood and in degrading pinewood into a uniform pulp, as revealed by scanning electron microscopy (SEM). The rate of enzymatic hydrolysis of pinewood extract reached 72.16%. The combinations of AmimCl pretreatment with steam explosion or with hot compressed water were effective in treating corn stover, whereas AmimCl treatment alone did not result in a significant improvement. Pinewood extract produced 20.7g/L succinic acid with an average yield of 0.37g per gram of biomass. Workflow calculations indicated pine wood pretreated with IL has a theoretical yield of succinic acid of 57.1%. IL pretreatment led to increase in succinic acid yields. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Norms, Standards, and Legislation for Fast Pyrolysis Bio-oils from Lignocellulosic Biomass

    SciTech Connect

    Oasmaa, Anja; van de Beld, Bert; Saari, Pia; Elliott, Douglas C.; Solantausta, Yrjo

    2015-04-16

    Fast pyrolysis of woody biomass is close to full maturity, with first-of-its-kind commercial size installations for fuel production being commissioned in Finland (Fortum) and in The Netherlands (Empyro), and in the design phase in Brazil (Ensyn). In the industrial-scale combustion tests, the use of fast pyrolysis bio-oil (FPBO) has been demonstrated to be a viable option to replace heavy fuel oil in district heating applications. Commercially usable district heating boilers and burners suitable for FPBO are available. There is research on diesel-engine and gas-turbine applications but, so far, no proven demonstrations. FPBO is completely different from mineral oils; hence, standards are needed. Analytical methods have been systematically validated and modifications to the standards as well as completely new methods have been made. Two ASTM burner fuel standards already exist and European boiler fuel grades are being developed under CEN. The focus on CEN standardization is on boiler use, because of its commercial readiness.

  5. Metabolic engineering of Zymomonas mobilis for 2,3-butanediol production from lignocellulosic biomass sugars

    DOE PAGES

    Yang, Shihui; Mohagheghi, Ali; Franden, Mary Ann; ...

    2016-09-02

    To develop pathways for advanced biofuel production, and to understand the impact of host metabolism and environmental conditions on heterologous pathway engineering for economic advanced biofuels production from biomass, we seek to redirect the carbon flow of the model ethanologen Zymomonas mobilis to produce desirable hydrocarbon intermediate 2,3-butanediol (2,3-BDO). 2,3-BDO is a bulk chemical building block, and can be upgraded in high yields to gasoline, diesel, and jet fuel. 2,3-BDO biosynthesis pathways from various bacterial species were examined, which include three genes encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase. Bioinformatics analysis was carried out to pinpoint potential bottlenecks formore » high 2,3-BDO production. Different combinations of 2,3-BDO biosynthesis metabolic pathways using genes from different bacterial species have been constructed. Our results demonstrated that carbon flux can be deviated from ethanol production into 2,3-BDO biosynthesis, and all three heterologous genes are essential to efficiently redirect pyruvate from ethanol production for high 2,3-BDO production in Z. mobilis. The down-selection of best gene combinations up to now enabled Z. mobilis to reach the 2,3-BDO production of more than 10 g/L from glucose and xylose, as well as mixed C6/C5 sugar streams derived from the deacetylation and mechanical refining process. In conclusion, this study confirms the value of integrating bioinformatics analysis and systems biology data during metabolic engineering endeavors, provides guidance for value-added chemical production in Z. mobilis, and reveals the interactions between host metabolism, oxygen levels, and a heterologous 2,3-BDO biosynthesis pathway. Taken together, this work provides guidance for future metabolic engineering efforts aimed at boosting 2,3-BDO titer anaerobically.« less

  6. Metabolic engineering of Zymomonas mobilis for 2,3-butanediol production from lignocellulosic biomass sugars.

    PubMed

    Yang, Shihui; Mohagheghi, Ali; Franden, Mary Ann; Chou, Yat-Chen; Chen, Xiaowen; Dowe, Nancy; Himmel, Michael E; Zhang, Min

    2016-01-01

    To develop pathways for advanced biofuel production, and to understand the impact of host metabolism and environmental conditions on heterologous pathway engineering for economic advanced biofuels production from biomass, we seek to redirect the carbon flow of the model ethanologen Zymomonas mobilis to produce desirable hydrocarbon intermediate 2,3-butanediol (2,3-BDO). 2,3-BDO is a bulk chemical building block, and can be upgraded in high yields to gasoline, diesel, and jet fuel. 2,3-BDO biosynthesis pathways from various bacterial species were examined, which include three genes encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase. Bioinformatics analysis was carried out to pinpoint potential bottlenecks for high 2,3-BDO production. Different combinations of 2,3-BDO biosynthesis metabolic pathways using genes from different bacterial species have been constructed. Our results demonstrated that carbon flux can be deviated from ethanol production into 2,3-BDO biosynthesis, and all three heterologous genes are essential to efficiently redirect pyruvate from ethanol production for high 2,3-BDO production in Z. mobilis. The down-selection of best gene combinations up to now enabled Z. mobilis to reach the 2,3-BDO production of more than 10 g/L from glucose and xylose, as well as mixed C6/C5 sugar streams derived from the deacetylation and mechanical refining process. This study confirms the value of integrating bioinformatics analysis and systems biology data during metabolic engineering endeavors, provides guidance for value-added chemical production in Z. mobilis, and reveals the interactions between host metabolism, oxygen levels, and a heterologous 2,3-BDO biosynthesis pathway. Taken together, this work provides guidance for future metabolic engineering efforts aimed at boosting 2,3-BDO titer anaerobically.

  7. Uniform-Format Solid Feedstock Supply System: A Commodity-Scale Design to Produce an Infrastructure-Compatible Bulk Solid from Lignocellulosic Biomass -- Executive Summary

    SciTech Connect

    J. Richard Hess; Christopher T. Wright; Kevin L. Kenney; Erin M. Searcy

    2009-04-01

    This report, Uniform-Format Solid Feedstock Supply System: A Commodity-Scale Design to Produce an Infrastructure-Compatible Bulk Solid from Lignocellulosic Biomass, prepared by Idaho National Laboratory (INL), acknowledges the need and provides supportive designs for an evolutionary progression from present day conventional bale-based supply systems to a uniform-format, bulk solid supply system that transitions incrementally as the industry launches and matures. These designs couple to and build from current state of technology and address science and engineering constraints that have been identified by rigorous sensitivity analyses as having the greatest impact on feedstock supply system efficiencies and costs.

  8. Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels Conversion Pathway: Fast Pyrolysis and Hydrotreating Bio-Oil Pathway "The 2017 Design Case"

    SciTech Connect

    Kevin L. Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J. Bonner; Garold L. Gresham; J. Richard Hess; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

    2014-01-01

    The U.S. Department of Energy promotes the production of liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass sustainable supply, logistics, conversion, and overall system sustainability. As part of its involvement in this program, Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL quantified and the economics and sustainability of moving biomass from the field or stand to the throat of the conversion process using conventional equipment and processes. All previous work to 2012 was designed to improve the efficiency and decrease costs under conventional supply systems. The 2012 programmatic target was to demonstrate a biomass logistics cost of $55/dry Ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model.

  9. Process Design and Economics for the Conversion of Lignocellulosic Biomass to High Octane Gasoline: Thermochemical Research Pathway with Indirect Gasification and Methanol Intermediate

    SciTech Connect

    Tan, Eric; Talmadge, M.; Dutta, Abhijit; Hensley, Jesse; Schaidle, Josh; Biddy, Mary J.; Humbird, David; Snowden-Swan, Lesley J.; Ross, Jeff; Sexton, Danielle; Yap, Raymond; Lukas, John

    2015-03-01

    The U.S. Department of Energy (DOE) promotes research for enabling cost-competitive liquid fuels production from lignocellulosic biomass feedstocks. The research is geared to advance the state of technology (SOT) of biomass feedstock supply and logistics, conversion, and overall system sustainability. As part of their involvement in this program, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) investigate the economics of conversion pathways through the development of conceptual biorefinery process models. This report describes in detail one potential conversion process for the production of high octane gasoline blendstock via indirect liquefaction (IDL). The steps involve the conversion of biomass to syngas via indirect gasification followed by gas cleanup and catalytic syngas conversion to a methanol intermediate; methanol is then further catalytically converted to high octane hydrocarbons. The conversion process model leverages technologies previously advanced by research funded by the Bioenergy Technologies Office (BETO) and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via tar and hydrocarbons reforming was one of the key technology advancements as part of that research. The process described in this report evaluates a new technology area with downstream utilization of clean biomass-syngas for the production of high octane hydrocarbon products through a methanol intermediate, i.e., dehydration of methanol to dimethyl ether (DME) which subsequently undergoes homologation to high octane hydrocarbon products.

  10. Phylogeny in Defining Model Plants for Lignocellulosic Ethanol Production: A Comparative Study of Brachypodium distachyon, Wheat, Maize, and Miscanthus x giganteus Leaf and Stem Biomass

    PubMed Central

    Meineke, Till; Manisseri, Chithra; Voigt, Christian A.

    2014-01-01

    The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108–117 mg ethanol·g−1 dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type. PMID:25133818

  11. Phylogeny in defining model plants for lignocellulosic ethanol production: a comparative study of Brachypodium distachyon, wheat, maize, and Miscanthus x giganteus leaf and stem biomass.

    PubMed

    Meineke, Till; Manisseri, Chithra; Voigt, Christian A

    2014-01-01

    The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108-117 mg ethanol·g(-1) dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type.

  12. Hemicelluloses negatively affect lignocellulose crystallinity for high biomass digestibility under NaOH and H2SO4 pretreatments in Miscanthus

    PubMed Central

    2012-01-01

    Background Lignocellulose is the most abundant biomass on earth. However, biomass recalcitrance has become a major factor affecting biofuel production. Although cellulose crystallinity significantly influences biomass saccharification, little is known about the impact of three major wall polymers on cellulose crystallization. In this study, we selected six typical pairs of Miscanthus samples that presented different cell wall compositions, and then compared their cellulose crystallinity and biomass digestibility after various chemical pretreatments. Results A Miscanthus sample with a high hemicelluloses level was determined to have a relatively low cellulose crystallinity index (CrI) and enhanced biomass digestibility at similar rates after pretreatments of NaOH and H2SO4 with three concentrations. By contrast, a Miscanthus sample with a high cellulose or lignin level showed increased CrI and low biomass saccharification, particularly after H2SO4 pretreatment. Correlation analysis revealed that the cellulose CrI negatively affected biomass digestion. Increased hemicelluloses level by 25% or decreased cellulose and lignin contents by 31% and 37% were also found to result in increased hexose yields by 1.3-times to 2.2-times released from enzymatic hydrolysis after NaOH or H2SO4 pretreatments. The findings indicated that hemicelluloses were the dominant and positive factor, whereas cellulose and lignin had synergistic and negative effects on biomass digestibility. Conclusions Using six pairs of Miscanthus samples with different cell wall compositions, hemicelluloses were revealed to be the dominant factor that positively determined biomass digestibility after pretreatments with NaOH or H2SO4 by negatively affecting cellulose crystallinity. The results suggested potential approaches to the genetic modifications of bioenergy crops. PMID:22883929

  13. Utilization of recombinant Trichoderma reesei expressing Aspergillus aculeatus β-glucosidase I (JN11) for a more economical production of ethanol from lignocellulosic biomass.

    PubMed

    Treebupachatsakul, Treesukon; Shioya, Koki; Nakazawa, Hikaru; Kawaguchi, Takashi; Morikawa, Yasushi; Shida, Yosuke; Ogasawara, Wataru; Okada, Hirofumi

    2015-12-01

    The capacity of Trichoderma reesei cellulase to degrade lignocellulosic biomass has been enhanced by the construction of a recombinant T. reesei strain expressing Aspergillus aculeatus β-glucosidase I. We have confirmed highly efficient ethanol production from converge-milled Japanese cedar by recombinant T. reesei expressing A. aculeatus β-glucosidase I (JN11). We investigated the ethanol productivity of JN11 and compared it with the cocktail enzyme T. reesei PC-3-7 with reinforced cellobiase activity by the commercial Novozyme 188. Results showed that the ethanol production efficiency under enzymatic hydrolysis of JN11 was comparable to the cocktail enzyme both on simultaneous saccharification and fermentation (SSF) or separate hydrolysis and fermentation (SHF) processes. Moreover, the cocktail enzyme required more protein loading for attaining similar levels of ethanol conversion as JN11. We propose that JN11 is an intrinsically economical enzyme that can eliminate the supplementation of BGL for PC-3-7, thereby reducing the cost of industrial ethanol production from lignocellulosic biomass.

  14. Asparagus stem as a new lignocellulosic biomass feedstock for anaerobic digestion: increasing hydrolysis rate, methane production and biodegradability by alkaline pretreatment.

    PubMed

    Chen, Xiaohua; Gu, Yu; Zhou, Xuefei; Zhang, Yalei

    2014-07-01

    Recently, anaerobic digestion of lignocellulosic biomass for methane production has attracted considerable attention. However, there is little information regarding methane production from asparagus stem, a typical lignocellulosic biomass, by anaerobic digestion. In this study, alkaline pretreatment of asparagus stem was investigated for its ability to increase hydrolysis rate and methane production and to improve biodegradability (BD). The hydrolysis rate increased with increasing NaOH dose, due to higher removal rates of lignin and hemicelluloses. However, the optimal NaOH dose was 6% (w/w) according to the specific methane production (SMP). Under this condition, the SMP and the technical digestion time of the NaOH-treated asparagus stem were 242.3 mL/g VS and 18 days, which were 38.4% higher and 51.4% shorter than those of the untreated sample, respectively. The BD was improved from 40.1% to 55.4%. These results indicate that alkaline pretreatment could be an efficient method for increasing methane production from asparagus stem. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Effects of the Surface Morphology and Conformations of Lignocellulosic Biomass Biopolymers on Their Nanoscale Interactions with Hydrophobic Self-Assembled Monolayers.

    PubMed

    Arslan, Baran; Egerton, Kirstin; Zhang, Xiao; Abu-Lail, Nehal I

    2017-07-11

    The effects of the morphology and conformations of the surface biopolymers present on lignocellulosic biomass as well as their steric hindrance on enzymatic adsorption to biomass surfaces remain elusive. In a step to better understand these effects, nanoscale steric forces between a model surface that represents the hydrophobic residues of a cellulase enzyme and a set of reference lignocellulosic substrates were measured using atomic force microscopy (AFM) in liquid media. The reference substrates investigated were prepared by kraft, sulfite, and organosolv pulping pretreatment methods and varied in their surface lignin, xylan, and acetone extractives' contents. Measured steric forces were quantified through fitting to a model developed to describe polyelectrolytes brushes in terms of a brush thickness and a brush grafting density. Our data indicated that cellulose microfibrils extend from the microfibril matrix leading to a long-range steric repulsion and low attractive forces to the hydrophobic model of the enzyme, suggesting that steric hindering can be a possible mechanism for nonproductive binding of enzymes to cellulose. When the amount of xylan increased in the absence of lignin, steric repulsions between the hydrophobic model of the enzyme, and biomass biopolymers decreased as a result of collapsed cellulose microfibrils and adhesion forces increased. This suggests that leaving a small amount of xylan after biomass pretreatment can help improve enzymatic binding to cellulose. Irrespective of the type of lignin present on biomass, grafting densities increased and brush thicknesses decreased compared to those of lignin-free substrates. When compared to lignin-free substrates, lignin-containing substrates had higher attractive forces and lower steric repulsive forces. In addition, AFM images of the reference substrates in the wet and dry states showed that lignin precipitates on the biomass surface where kraft lignin had the highest particle size leading to a

  16. Fast microwave-assisted acidolysis: a new biorefinery approach for the zero-waste utilisation of lignocellulosic biomass to produce high quality lignin and fermentable saccharides.

    PubMed

    Zhou, Long; Santomauro, Fabio; Fan, Jiajun; Macquarrie, Duncan; Clark, James; Chuck, Christopher J; Budarin, Vitaliy

    2017-09-21

    Generally, biorefineries convert lignocellulosic biomass into a range of biofuels and further value added chemicals. However, conventional biorefinery processes focus mainly on the cellulose and hemicellulose fractions and therefore produce only low quality lignin, which is commonly burnt to provide process heat. To make full use of the biomass, more attention needs to be focused on novel separation techniques, where high quality lignin can be isolated that is suitable for further valorisation into aromatic chemicals and fuel components. In this paper, three types of lignocellulosic biomass (softwood, hardwood and herbaceous biomass) were processed by microwave-assisted acidolysis to produce high quality lignin. The lignin from the softwood was isolated largely intact in the solid residue after acidolysis. For example, a 10 min microwave-assisted acidolysis treatment produced lignin with a purity of 93% and in a yield of 82%, which is superior to other conventional separation methods reported. Furthermore, py-GC/MS analysis proved that the isolated lignin retained the original structure of native lignin in the feedstock without severe chemical modification. This is a large advantage, and the purified lignin is suitable for further chemical processing. To assess the suitability of this methodology as part of a biorefinery system, the aqueous phase, produced after acidolysis of the softwood, was characterised and assessed for its suitability for fermentation. The broth contained some mono- and di-saccharides but mainly contained organic acids, oligosaccharides and furans. While this is unsuitable for S. cerevisiae and other common ethanol producing yeasts, two oleaginous yeasts with known inhibitor tolerances were selected: Cryptococcus curvatus and Metschnikowia pulcherrima. Both yeasts could grow on the broth, and demonstrated suitable catabolism of the oligosaccharides and inhibitors over 7 days. In addition, both yeasts were shown to be able to produce an oil

  17. [Progress in lignocellulose deconstruction by fungi].

    PubMed

    Tian, Chaoguang; Ma, Yanhe

    2010-10-01

    Inefficient degradation of lignocellulose is one of the main barriers for the utilization of renewable plant biomass for biofuel production. The bottleneck of the biorefinery process is the generation of fermentable sugars from complicated biomass polymers. In nature, the main microbes of lignocelluloses deconstruction are fungi. Therefore, elucidating the mechanism of lignocelluloses degradation by fungi is of critical importance for the commercialization of lignocellulosic biofuels. This review focuses on the progress in lignocelluloses degradation pathways in fungi, especially on the advances made by functional genomics studies.

  18. Pretreating lignocellulosic biomass by the concentrated phosphoric acid plus hydrogen peroxide (PHP) for enzymatic hydrolysis: evaluating the pretreatment flexibility on feedstocks and particle sizes.

    PubMed

    Wang, Qing; Wang, Zhanghong; Shen, Fei; Hu, Jinguang; Sun, Fubao; Lin, Lili; Yang, Gang; Zhang, Yanzong; Deng, Shihuai

    2014-08-01

    In order to seek a high-efficient pretreatment path for converting lignocellulosic feedstocks to fermentable sugars by enzymatic hydrolysis, the concentrated H₃PO₄ plus H₂O₂ (PHP) was attempted to pretreat different lignocellulosic biomass for evaluating the pretreatment flexibility on feedstocks. Meanwhile, the responses of pretreatment to particle sizes were also evaluated. When the PHP-pretreatment was employed (final H₂O₂ and H₃PO₄ concentration of 1.77% and 80.0%), 71-96% lignin and more than 95% hemicellulose in various feedstocks (agricultural residues, hardwood, softwood, bamboo, and their mixture, and garden wastes mixture) can be removed. Consequently, more than 90% glucose conversion was uniformly achieved indicating PHP greatly improved the pretreatment flexibility to different feedstocks. Moreover, when wheat straw and oak chips were PHP-pretreated with different sizes, the average glucose conversion reached 94.9% and 100% with lower coefficient of variation (7.9% and 0.0%), which implied PHP-pretreatment can significantly weaken the negative effects of feedstock sizes on subsequent conversion.

  19. Selection of discriminant mid-infrared wavenumbers by combining a naïve Bayesian classifier and a genetic algorithm: Application to the evaluation of lignocellulosic biomass biodegradation.

    PubMed

    Rammal, Abbas; Perrin, Eric; Vrabie, Valeriu; Assaf, Rabih; Fenniri, Hassan

    2017-07-01

    Infrared spectroscopy provides useful information on the molecular compositions of biological systems related to molecular vibrations, overtones, and combinations of fundamental vibrations. Mid-infrared (MIR) spectroscopy is sensitive to organic and mineral components and has attracted growing interest in the development of biomarkers related to intrinsic characteristics of lignocellulose biomass. However, not all spectral information is valuable for biomarker construction or for applying analysis methods such as classification. Better processing and interpretation can be achieved by identifying discriminating wavenumbers. The selection of wavenumbers has been addressed through several variable- or feature-selection methods. Some of them have not been adapted for use in large data sets or are difficult to tune, and others require additional information, such as concentrations. This paper proposes a new approach by combining a naïve Bayesian classifier with a genetic algorithm to identify discriminating spectral wavenumbers. The genetic algorithm uses a linear combination of an a posteriori probability and the Bayes error rate as the fitness function for optimization. Such a function allows the improvement of both the compactness and the separation of classes. This approach was tested to classify a small set of maize roots in soil according to their biodegradation process based on their MIR spectra. The results show that this optimization method allows better discrimination of the biodegradation process, compared with using the information of the entire MIR spectrum, the use of the spectral information at wavenumbers selected by a genetic algorithm based on a classical validity index or the use of the spectral information selected by combining a genetic algorithm with other methods, such as Linear Discriminant Analysis. The proposed method selects wavenumbers that correspond to principal vibrations of chemical functional groups of compounds that undergo degradation

  20. Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Conversion Pathway: Biological Conversion of Sugars to Hydrocarbons The 2017 Design Case

    SciTech Connect

    Kevin Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J Bonner; Garold L. Gresham; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

    2013-09-01

    The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL conducted a campaign to quantify the economics and sustainability of moving biomass from standing in the field or stand to the throat of the biomass conversion process. The goal of this program was to establish the current costs based on conventional equipment and processes, design improvements to the current system, and to mark annual improvements based on higher efficiencies or better designs. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $35/dry ton. This goal was successfully achieved in 2012 by implementing field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. Looking forward to 2017, the programmatic target is to supply biomass to the conversion facilities at a total cost of $80/dry ton and on specification with in-feed requirements. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, abundant, low-cost feedstock. If this goal is not achieved, biofuel plants are destined to be small and/or clustered in select regions of the country that have a lock on low-cost feedstock. To put the 2017 cost target into perspective of past accomplishments of the cellulosic ethanol pathway, the $80 target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all

  1. Evaluation of the biomass potential for the production of lignocellulosic bioethanol from various agricultural residues in Austria and Worldwide

    NASA Astrophysics Data System (ADS)

    Kahr, Heike; Steindl, Daniel; Wimberger, Julia; Schürz, Daniel; Jäger, Alexander

    2013-04-01

    Due to the fact that the resources of fossil fuels are steadily decreasing, researchers have been trying to find alternatives over the past few years. As bioethanol of the first generation is based on potential food, its production has become an increasingly controversial topic. Therefore the focus of research currently is on the production of bioethanol of the second generation, which is made from cellulosic and lignocellulosic materials. However, for the production of bioethanol of the second generation the fibres have to be pre-treated. In this work the mass balances of various agricultural residues available in Austria were generated and examined in lab scale experiments for their bioethanol potential. The residues were pretreatment by means of state of the art technology (steam explosion), enzymatically hydrolysed and fermented with yeast to produce ethanol. Special attention was paid the mass balance of the overall process. Due to the pretreatment the proportion of cellulose increases with the duration of the pre-treatment, whereby the amount of hemicellulose decreases greatly. However, the total losses were increasing with the duration of the pre-treatment, and the losses largely consist of hemicellulose. The ethanol yield varied depending on the cellulose content of the substrates. So rye straw 200 °C 20 min reaches an ethanol yield of 169 kg/t, by far the largest yield. As result on the basis of the annual straw yield in Austria, approximately 210 000 t of bioethanol (266 million litres) could be produced from the straw of wheat (Triticum vulgare), rye (Secale cereale), oat (Avena sativa) and corn (Zea mays) as well as elephant grass (Miscanthus sinensis) using appropriate pre-treatment. So the greenhouse gas emissions produced by burning fossil fuels could be reduced significantly. About 1.8 million tons of motor gasoline are consumed in Austria every year. The needed quantity for a transition to E10 biofuels could thus be easily provided by bioethanol

  2. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

    PubMed

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion.

  3. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411

    PubMed Central

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47–0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2–2.7 g/L/h and a total sugar conversion of 90–99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

  4. An advanced understanding of the specific effects of xylan and surface lignin contents on enzymatic hydrolysis of lignocellulosic biomass

    SciTech Connect

    Ju, Xiaohui; Engelhard, Mark H.; Zhang, Xiao

    2013-01-17

    A deep understanding of biomass recalcitrance has been hampered by the intricate and heterogeneous nature of pretreated biomass substrates obtained from random deconstruction methods. In this study, we established a unique methodology based on chemical pulping principles to create "reference substrates" with intact cellulose fibers and controlled morphological and chemical properties that enable us to investigate the individual effect of xylan, bulk, and surface lignin content on enzymatic hydrolysis. We also developed and demonstrated an X-ray photoelectron spectroscopy (XPS) technique for quantifying surface lignin content on biomass substrates. The results from this study show that, apart from its hindrance effect, xylan can facilitate cellulose fibril swelling and thus create more accessible surface area, which improves enzyme and substrate interactions. Surface lignin has a significant impact on enzyme adsorption kinetics and hydrolysis rate. Advanced understanding of xylan, bulk, and surface lignin effects provides critical information for an effective biomass conversion process.

  5. Rheology of concentrated biomass

    Treesearch

    J.R. Samaniuk; J. Wang; T.W. Root; C.T. Scott; D.J. Klingenberg

    2011-01-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained...

  6. Silica distinctively affects cell wall features and lignocellulosic saccharification with large enhancement on biomass production in rice.

    PubMed

    Zhang, Jing; Zou, Weihua; Li, Ying; Feng, Yongqing; Zhang, Hui; Wu, Zhiliang; Tu, Yuanyuan; Wang, Yanting; Cai, Xiwen; Peng, Liangcai

    2015-10-01

    Rice is a typical silicon-accumulating crop with enormous biomass residues for biofuels. Silica is a cell wall component, but its effect on the plant cell wall and biomass production remains largely unknown. In this study, a systems biology approach was performed using 42 distinct rice cell wall mutants. We found that silica levels are significantly positively correlated with three major wall polymers, indicating that silica is associated with the cell wall network. Silicon-supplied hydroculture analysis demonstrated that silica distinctively affects cell wall composition and major wall polymer features, including cellulose crystallinity (CrI), arabinose substitution degree (reverse Xyl/Ara) of xylans, and sinapyl alcohol (S) proportion in three typical rice mutants. Notably, the silicon supplement exhibited dual effects on biomass enzymatic digestibility in the mutant and wild type (NPB) after pre-treatments with 1% NaOH and 1% H2SO4. In addition, silicon supply largely enhanced plant height, mechanical strength and straw biomass production, suggesting that silica rescues mutant growth defects. Hence, this study provides potential approaches for silicon applications in biomass process and bioenergy rice breeding.

  7. Development of next generation biocatalyst for lower-cost ethanol production from lignocellulose

    USDA-ARS?s Scientific Manuscript database

    Economics of fermentation-based biotechnology rely extensively on microbial performance. For renewable ethanol production using lignocellulosic biomass feedstocks, two major technical challenges exist. First, inhibitory compounds liberated from lignocellulosic biomass pretreatment interfere with m...

  8. Microwave-assisted catalytic pyrolysis of lignocellulosic biomass for production of phenolic-rich bio-oil.

    PubMed

    Mamaeva, Alisa; Tahmasebi, Arash; Tian, Lu; Yu, Jianglong

    2016-07-01

    Catalytic microwave pyrolysis of peanut shell (PT) and pine sawdust (PS) using activated carbon (AC) and lignite char (LC) for production of phenolic-rich bio-oil and nanotubes was investigated in this study. The effects of process parameters such as pyrolysis temperature and biomass/catalyst ratio on the yields and composition of pyrolysis products were investigated. Fast heating rates were achieved under microwave irradiation conditions. Gas chromatography-mass spectrometry (GC-MS) analysis of bio-oil showed that activated carbon significantly enhanced the selectivity of phenolic compounds in bio-oil. The highest phenolics content in the bio-oil (61.19 %(area)) was achieved at 300°C. The selectivity of phenolics in bio-oil was higher for PT sample compared to that of PS. The formation of nanotubes in PT biomass particles was observed for the first time in biomass microwave pyrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover

    SciTech Connect

    Aden, A.; Ruth, M.; Ibsen, K.; Jechura, J.; Neeves, K.; Sheehan, J.; Wallace, B.; Montague, L.; Slayton, A.; Lukas, J.

    2002-06-01

    This report is an update of NREL's ongoing process design and economic analyses of processes related to developing ethanol from lignocellulosic feedstocks. The U.S. Department of Energy (DOE) is promoting the development of ethanol from lignocellulosic feedstocks as an alternative to conventional petroleum-based transportation fuels. DOE funds both fundamental and applied research in this area and needs a method for predicting cost benefits of many research proposals. To that end, the National Renewable Energy Laboratory (NREL) has modeled many potential process designs and estimated the economics of each process during the last 20 years. This report is an update of the ongoing process design and economic analyses at NREL. We envision updating this process design report at regular intervals; the purpose being to ensure that the process design incorporates all new data from NREL research, DOE funded research and other sources, and that the equipment costs are reasonable and consistent with good engineering practice for plants of this type. For the non-research areas this means using equipment and process approaches as they are currently used in industrial applications. For the last report, published in 1999, NREL performed a complete review and update of the process design and economic model for the biomass-to-ethanol process utilizing co-current dilute acid prehydrolysis with simultaneous saccharification (enzymatic) and co-fermentation. The process design included the core technologies being researched by the DOE: prehydrolysis, simultaneous saccharification and co-fermentation, and cellulase enzyme production. In addition, all ancillary areas--feed handling, product recovery and purification, wastewater treatment (WWT), lignin combustor and boiler-turbogenerator, and utilities--were included. NREL engaged Delta-T Corporation (Delta-T) to assist in the process design evaluation, the process equipment costing, and overall plant integration. The process design and

  10. Removal and recovery of cobalt from aqueous solutions by adsorption using low cost lignocellulosic biomass--coir pith.

    PubMed

    Parab, Harshala; Joshi, Shreeram; Sudersanan, M; Shenoy, Niyoti; Lali, Arvind; Sarma, Umashankar

    2010-01-01

    The applicability of low-cost lignocellulosic biosorbent-coir pith, for removal of cobalt (II) from aqueous solutions using batch adsorption studies has been explored herein. Adsorption characteristics of coir pith were investigated systematically by varying the experimental parameters such as, solution pH, initial metal ion concentration, contact time, adsorbent dose and temperature. The studies revealed that optimum adsorption of cobalt onto coir pith occurred in the pH range of 4.0 - 7.0. Sorption kinetics of cobalt was found to be quite rapid under ambient conditions and the process followed second-order kinetics. The experimental data have been analyzed using non-linearized forms of Langmuir, Freundlich and Redlich-Peterson adsorption isotherms for mathematical description of the process. Desorption studies showed that the quantitative recovery of Co (II) from the spent coir pith was achieved by using 0.5 N HCl. The suitability of this adsorbent for real situation has been observed, when complete removal of cobalt from nuclear power plant coolant water was obtained. The present studies successfully demonstrated the use of coir pith as an efficient adsorbent material for removal of cobalt from aqueous solutions.

  11. Process strategies for high titers of lipid production by oleaginous yeasts in undetoxified hydrolyzates of lignocellulosic biomass

    USDA-ARS?s Scientific Manuscript database

    Oleaginous yeasts can accumulate up to 70% of cell biomass as lipid, predominantly as triacylglycerols. Yeast lipid fatty acid profiles have been reported to be similar to that of vegetable oils and consist primarily of oleic, palmitic, stearic, and linoleic acids. This capability provides the oppor...

  12. Ethanol and high-value terpene co-production from lignocellulosic biomass of Cymbopogon flexuosus and Cymbopogon martinii

    USDA-ARS?s Scientific Manuscript database

    Cymbopogon flexuosus and C. martinii are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosi...

  13. Production of light olefins by catalytic conversion of lignocellulosic biomass with HZSM-5 zeolite impregnated with 6wt.% lanthanum.

    PubMed

    Huang, Weiwei; Gong, Feiyan; Fan, Minghui; Zhai, Qi; Hong, Chenggui; Li, Quanxin

    2012-10-01

    Catalytic conversion of rice husk, sawdust, sugarcane bagasse, cellulose, hemicellulose and lignin into olefins was performed with HZSM-5 containing 6 wt.% lanthanum. The olefins yields for different feedstocks decreased in the order: cellulose>hemicellulose>sugarcane bagasse>rice husk>sawdust>lignin. Biomass containing higher content of cellulose or hemicellulose produced more olefins than feedstocks with higher content of lignin. Among the biomass types, sugarcane bagasse provided the highest olefin yield of 0.12 kg olefins/(kg dry biomass) and carbon yield of 21.2C-mol%. Temperature, residence time and the catalyst/feed ratio influenced olefin yield and selectivity. While the HZSM-5 zeolite was catalytically active, the incorporation of lanthanum at 2.9, and 6.0 wt.% increased the production of olefins from rice husk by 15.6% and 26.5%, respectively. The conversion of biomass to light olefins potentially provides an alternative and sustainable route for production of the key petrochemicals.

  14. Steam-exploded biomass saccharification is predominately affected by lignocellulose porosity and largely enhanced by Tween-80 in Miscanthus.

    PubMed

    Sun, Dan; Alam, Aftab; Tu, Yuanyuan; Zhou, Shiguang; Wang, Yanting; Xia, Tao; Huang, Jiangfeng; Li, Ying; Zahoor; Wei, Xiaoyang; Hao, Bo; Peng, Liangcai

    2017-09-01

    In this study, total ten Miscanthus accessions exhibited diverse cell wall compositions, leading to largely varied hexoses yields at 17%-40% (% cellulose) released from direct enzymatic hydrolysis of steam-exploded (SE) residues. Further supplied with 2% Tween-80 into the enzymatic digestion, the Mis7 accession showed the higher hexose yield by 14.8-fold than that of raw material, whereas the Mis10 had the highest hexoses yield at 77% among ten Miscanthus accessions. Significantly, this study identified four wall polymer features that negatively affect biomass saccharification as p<0.05 or 0.01 in the SE residues, including cellulose DP, Xyl and Ara of hemicellulose, and S-monomer of lignin. Based on Simons' stain, the SE porosity (defined by DY/DB) was examined to be the unique positive factor on biomass enzymatic digestion. Hence, this study provides the potential strategy to enhance biomass saccharification using optimal biomass process technology and related genetic breeding in Miscanthus and beyond. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Simultaneous saccharification and fermentation of delignified lignocellulosic biomass at high solid loadings by a newly isolated thermotolerant Kluyveromyces sp. for ethanol production.

    PubMed

    Narra, Madhuri; James, Jisha P; Balasubramanian, Velmurugan

    2015-03-01

    Simultaneous saccharification and fermentation studies were carried out using thermotolerant newly isolated Kluyveromyces sp. with three different delignified lignocellulosic biomass viz. rice straw, wheat straw and sugarcane bagasse at 5-15% solid loading and 6-12 FPU g(-1) substrate enzyme loading for different time intervals 0-72 h at 42°C. Maximum ethanol achieved from rice straw, wheat straw and sugarcane bagasse with in-house crude cellulases from Aspergillus terreus was 23.23, 18.29 and 17.91 mg mL(-1) at 60 h with 10% solid load and 9 FPU g(-1) substrate enzyme loading. Tween 80 1% (v/v) enhanced the ethanol yield by 8.39%, 9.26% and 8.14% in rice straw, wheat straw and sugarcane bagasse, respectively. External supplementation of β-glucosidase to the crude as well commercial cellulases produced maximum theoretical ethanol yield of 71.76%, 63.77%, 57.15% and 84.56%, 72.47%, 70.55% from rice straw, wheat straw and sugarcane bagasse, respectively.

  16. Characterization of a thermophilic cellulase from Geobacillus sp. HTA426, an efficient cellulase-producer on alkali pretreated of lignocellulosic biomass.

    PubMed

    Potprommanee, Laddawan; Wang, Xiao-Qin; Han, Ye-Ju; Nyobe, Didonc; Peng, Yen-Ping; Huang, Qing; Liu, Jing-Yong; Liao, Yu-Ling; Chang, Ken-Lin

    2017-01-01

    A themophilic cellulase-producing bacterium was isolated from a hot spring district and identified as Geobacillus sp. HTA426. The cellulase enzyme produced by the Geobacillus sp. HTA426 was purified through ammonium sulfate precipitation and ion exchange chromatography, with the recovery yield and fold purification of 10.14% and 5.12, respectively. The purified cellulase has a molecular weight of 40 kDa. The optimum temperature and pH for carboxymethyl cellulase (CMCase) activity of the purified cellulase were 60°C and pH 7.0, respectively. The enzyme was also stable over a wide temperature range of 50°C to 70°C after 5 h of incubation. Moreover, the strain HTA426 was able to grow and produce cellulase on alkali-treated sugarcane bagasse, rice straw and water hyacinth as carbon sources. Enzymatic hydrolysis of sugarcane bagasse, which was regarded as the most effective carbon source for cellulase production (CMCase activity = 103.67 U/mL), followed by rice straw (74.70 U/mL) and water hyacinth (51.10 U/mL). This strain producing an efficient thermostable cellulose is a potential candidate for developing a more efficient and cost-effective process for converting lignocellulosic biomass into biofuel and other industrial process.

  17. YNL134C from Saccharomyces cerevisiae encodes a novel protein with aldehyde reductase activity for detoxification of furfural derived from lignocellulosic biomass.

    PubMed

    Zhao, Xianxian; Tang, Juan; Wang, Xu; Yang, Ruoheng; Zhang, Xiaoping; Gu, Yunfu; Li, Xi; Ma, Menggen

    2015-05-01

    Furfural and 5-hydroxymethylfurfural (HMF) are the two main aldehyde compounds derived from pentoses and hexoses, respectively, during lignocellulosic biomass pretreatment. These two compounds inhibit microbial growth and interfere with subsequent alcohol fermentation. Saccharomyces cerevisiae has the in situ ability to detoxify furfural and HMF to the less toxic 2-furanmethanol (FM) and furan-2,5-dimethanol (FDM), respectively. Herein, we report that an uncharacterized gene, YNL134C, was highly up-regulated under furfural or HMF stress and Yap1p and Msn2/4p transcription factors likely controlled its up-regulated expression. Enzyme activity assays showed that YNL134C is an NADH-dependent aldehyde reductase, which plays a role in detoxification of furfural to FM. However, no NADH- or NADPH-dependent enzyme activity was observed for detoxification of HMF to FDM. This enzyme did not catalyse the reverse reaction of FM to furfural or FDM to HMF. Further studies showed that YNL134C is a broad-substrate aldehyde reductase, which can reduce multiple aldehydes to their corresponding alcohols. Although YNL134C is grouped into the quinone oxidoreductase family, no quinone reductase activity was observed using 1,2-naphthoquinone or 9,10-phenanthrenequinone as a substrate, and phylogenetic analysis indicates that it is genetically distant to quinone reductases. Proteins similar to YNL134C in sequence from S. cerevisiae and other microorganisms were phylogenetically analysed.

  18. Growth of oleaginous Rhodotorula glutinis in an internal-loop airlift bioreactor by using lignocellulosic biomass hydrolysate as the carbon source.

    PubMed

    Yen, Hong-Wei; Chang, Jung-Tzu

    2015-05-01

    The conversion of abundant lignocellulosic biomass (LCB) to valuable compounds has become a very attractive idea recently. This study successfully used LCB (rice straw) hydrolysate as a carbon source for the cultivation of oleaginous yeast-Rhodotorula glutinis in an airlift bioreactor. The lipid content of 34.3 ± 0.6% was obtained in an airlift batch with 60 g reducing sugars/L of LCB hydrolysate at a 2 vvm aeration rate. While using LCB hydrolysate as the carbon source, oleic acid (C18:1) and linoleic acid (C18:2) were the predominant fatty acids of the microbial lipids. Using LCB hydrolysate in the airlift bioreactor at 2 vvm achieved the highest cell mass growth as compared to the agitation tank. Despite the low lipid content of the batch using LCB hydrolysate, this low cost feedstock has the potential of being adopted for the production of β-carotene instead of lipid accumulation in the airlift bioreactor for the cultivation of R. glutinis.

  19. Comprehensive analysis of the cellulolytic system reveals its potential for deconstruction of lignocellulosic biomass in a novel Streptomyces sp.

    PubMed

    Pinheiro, Guilherme L; de Azevedo-Martins, Allan C; Albano, Rodolpho M; de Souza, Wanderley; Frases, Susana

    2017-01-01

    The giant snail Achatina fulica is considered an invasive species in most territories in which it was introduced, due to its ability to process a large amount of lignocellulose as a consequence of the presence of a cellulolytic-associated microflora. Streptomyces are well known as crucial agents in the decomposition of complex polymers in soil environments and also as cellulolytic symbionts commonly associated with herbivore insects. Here, we employed a combination of genomic and biochemical tools for a detailed evaluation of the cellulolytic potential of Streptomyces sp. I1.2, an aerobic bacterium isolated from the intestinal lumen of A. fulica in a screening for cellulolytic bacteria. Genomic analysis revealed that the ratio and diversity of CAZy domains and GH families coded by Streptomyces sp. I1.2 are comparable to those present in other highly cellulolytic bacteria. After growth on crystalline cellulose or sugarcane bagasse as sole carbon sources, the functionality of several genes encoding endoglucanases, cellobiohydrolases, xylanases, CBMs, and one β-glucosidase were confirmed by the combination of enzymatic activity measurements, zymography, TLC, and cellulose-binding assays. The endoglucanases secreted by this isolate were stable at 50 °C and exhibited activity over a broad pH range between 4.0 and 8.0. The endoglucanases and cellobiohydrolases secreted by Streptomyces sp. I1.2 exhibited specific activities that were similar to the levels present in a commercial cellulase preparation from Trichoderma reesei, while I1.2 xylanase levels were even 350 % higher. The results presented here show that Streptomyces sp. I1.2 is promising for future biotechnological applications, since it is able to produce endoglucanases, cellobiohydrolases, and xylanases in appreciable amounts when grown on a low-cost residue such as sugarcane bagasse.

  20. Enhancing the enzymatic hydrolysis of lignocellulosic biomass by increasing the carboxylic acid content of the associated lignin.

    PubMed

    Nakagame, Seiji; Chandra, Richard P; Kadla, John F; Saddler, Jack N

    2011-03-01

    To assess the effects that the physical and chemical properties of lignin might have on the enzymatic hydrolysis of pretreated lignocellulosic substrates, protease treated lignin (PTL) and cellulolytic enzyme lignin (CEL) fractions, isolated from steam and organosolv pretreated corn stover, poplar, and lodgepole pine, were prepared and characterized. The adsorption of cellulases to the isolated lignin preparations corresponded to a Langmuir adsorption isotherm. It was apparent that, rather than the physical properties of the isolated lignin, the carboxylic acid functionality of the isolated lignin, as determined by FTIR and NMR spectroscopy, had much more of an influence when lignin was added to typical hydrolysis of pure cellulose (Avicel). An increase in the carboxylic content of the lignin preparation resulted in an increased hydrolysis yield. These results suggested that the carboxylic acids within the lignin partially alleviate non-productive binding of cellulases to lignin. To try to confirm this possible mechanism, dehydrogenative polymers (DHP) of monolignols were synthesized from coniferyl alcohol (CA) and ferulic acid (FA), and these model compounds were added to a typical enzymatic hydrolysis of Avicel. The DHP from FA, which was enriched in carboxylic acid groups compared with the DHP from CA, adsorbed a lower mount of cellulases and did not decrease hydrolysis yields when compared to the DHP from CA, which decreased the hydrolysis of Avicel by 8.4%. Thus, increasing the carboxylic acid content of the lignin seemed to significantly decrease the non-productive binding of cellulases and consequently increased the enzymatic hydrolysis of the cellulose. Copyright © 2010 Wiley Periodicals, Inc.

  1. Binding characteristics of Trichoderma reesei cellulases on untreated, ammonia fiber expansion (AFEX), and dilute-acid pretreated lignocellulosic biomass.

    PubMed

    Gao, Dahai; Chundawat, Shishir P S; Uppugundla, Nirmal; Balan, Venkatesh; Dale, Bruce E

    2011-08-01

    Studying the binding properties of cellulases to lignocellulosic substrates is critical to achieving a fundamental understanding of plant cell wall saccharification. Lignin auto-fluorescence and degradation products formed during pretreatment impede accurate quantification of individual glycosyl hydrolases (GH) binding to pretreated cell walls. A high-throughput fast protein liquid chromatography (HT-FPLC)-based method has been developed to quantify cellobiohydrolase I (CBH I or Cel7A), cellobiohydrolase II (CBH II or Cel6A), and endoglucanase I (EG I or Cel7B) present in hydrolyzates of untreated, ammonia fiber expansion (AFEX), and dilute-acid pretreated corn stover (CS). This method can accurately quantify individual enzymes present in complex binary and ternary protein mixtures without interference from plant cell wall-derived components. The binding isotherms for CBH I, CBH II, and EG I were obtained after incubation for 2 h at 4 °C. Both AFEX and dilute acid pretreatment resulted in increased cellulase binding compared with untreated CS. Cooperative binding of CBH I and/or CBH II in the presence of EG I was observed only for AFEX treated CS. Competitive binding between enzymes was found for certain other enzyme-substrate combinations over the protein loading range tested (i.e., 25-450 mg/g glucan). Langmuir single-site adsorption model was fitted to the binding isotherm data to estimate total available binding sites E(bm) (mg/g glucan) and association constant K(a) (L/mg). Our results clearly demonstrate that the characteristics of cellulase binding depend not only on the enzyme GH family but also on the type of pretreatment method employed. Copyright © 2011 Wiley Periodicals, Inc.

  2. Scale-up study of oxalic acid pretreatment of agricultural lignocellulosic biomass for the production of bioethanol

    Treesearch

    Jae-Won Lee; Carl J. Houtman; Hye-Yun Kim; In-Gyu Choi; Thomas W. Jeffries

    2011-01-01

    Building on our laboratory-scale optimization, oxalic acid was used to pretreat corncobs on the pilotscale. The hydrolysate obtained after washing the pretreated biomass contained 32.55 g/l of xylose, 2.74 g/l of glucose and low concentrations of inhibitors. Ethanol production, using Scheffersomyces stipitis, from this hydrolysate was 10.3 g/l, which approached the...

  3. Effects of Kraft lignin on hydrolysis/dehydration of sugars, cellulosic and lignocellulosic biomass under hot compressed water.

    PubMed

    Daorattanachai, Pornlada; Viriya-empikul, Nawin; Laosiripojana, Navadol; Faungnawakij, Kajornsak

    2013-09-01

    The effect of Kraft lignin presenting on the hydrolysis and dehydration of C5 and C6 sugars, cellulose, hemicelluloses and biomass under hot compressed water (HCW) in the presence of H3PO4 catalyst was intensively studied. The lignin strongly inhibited the acid hydrolysis of cellulose and hemicellulose to glucose and xylose, respectively. Interestingly, the admixed lignin markedly promoted the isomerization of glucose to fructose, and dehydration of fructose (except at the low catalyst loading), resulting in high 5-hydroxymethylfurfural yields. Nonetheless, lignin inhibited the hydrolysis of xylan to xylose and dehydration of xylose to furfural. Moreover, the acidity of the system significantly affects the hydrolysis/dehydration of biomass. It was revealed that the presence of lignin strongly interfered the yields of sugars and furans produced from raw corncob, while the delignified corncob provided significant improvement of product yields, confirming the observed role of lignin in the biomass conversion system via sugar platforms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Hydrolysis/dehydration/aldol-condensation/hydrogenation of lignocellulosic biomass and biomass-derived carbohydrates in the presence of Pd/WO3-ZrO2 in a single reactor.

    PubMed

    Dedsuksophon, W; Faungnawakij, K; Champreda, V; Laosiripojana, N

    2011-01-01

    Hydrolysis/dehydration/aldol-condensation/hydrogenation of lignocellulosic-biomass (corncobs) and biomass-derived carbohydrates (tapioca flour) to produce water-soluble C5-C15 compounds was developed in a single reactor system. WO3-ZrO2 efficiently catalyzed the hydrolysis/dehydration of these feedstocks to 5-hydroxymethylfurfural and furfural, while the impregnation of WO3-ZrO2 with Pd allowed sequential aldolcondensation/hydrogenation of these furans to C5-C15 compounds. The highest C5-C15 yields of 14.8-20.3% were observed at a hydrolysis/dehydration temperature of 573 K for 5 min, an aldol-condensation temperature of 353 K for 30 h, and a hydrogenation temperature of 393 K for 6 h. The C5-C15 yield from tapioca flour was higher than that from corncobs (20.3% compared to 14.8%). Tapioca flour produced more C6/C9/C15, whereas corncobs generated more C5/C8/C13 compounds due to the presence of hemicellulose in the corncobs. These water-soluble organic compounds can be further converted to liquid alkanes with high cetane numbers for replacing diesel fuel in transportation applications.

  5. Growth and enzymatic activity of Leucoagaricus gongylophorus, a mutualistic fungus isolated from the leaf-cutting ant Atta mexicana, on cellulose and lignocellulosic biomass.

    PubMed

    Vigueras, G; Paredes-Hernández, D; Revah, S; Valenzuela, J; Olivares-Hernández, R; Le Borgne, S

    2017-08-01

    A mutualistic fungus of the leaf-cutting ant Atta mexicana was isolated and identified as Leucoagaricus gongylophorus. This isolate had a close phylogenetic relationship with L. gongylophorus fungi cultivated by other leaf-cutting ants as determined by ITS sequencing. A subcolony started with ~500 A. mexicana workers could process 2 g day(-1) of plant material and generate a 135 cm(3) fungus garden in 160 days. The presence of gongylidia structures of ~35 μm was observed on the tip of the hyphae. The fungus could grow without ants on semi-solid cultures with α-cellulose and microcrystalline cellulose and in solid-state cultures with grass and sugarcane bagasse, as sole sources of carbon. The maximum CO2 production rate on grass (Vmax  = 17·5 mg CO2  Lg(-1)  day(-1) ) was three times higher than on sugarcane bagasse (Vmax  = 6·6 mg CO2  Lg(-1) day(-1) ). Recoveries of 32·9 mgglucose  gbiomass(-1) and 12·3 mgglucose  gbiomass(-1) were obtained from the fungal biomass and the fungus garden, respectively. Endoglucanase activity was detected on carboxymethylcellulose agar plates. This is the first study reporting the growth of L. gongylophorus from A. mexicana on cellulose and plant material. According to the best of our knowledge, this is the first report about the growth of Leucoagaricus gongylophorus, isolated from the colony of the ant Atta mexicana, on semisolid medium with cellulose and solid-state cultures with lignocellulosic materials. The maximum CO2 production rate on grass was three times higher than on sugarcane bagasse. Endoglucanase activity was detected and it was possible to recover glucose from the fungal gongylidia. The cellulolytic activity could be used to process lignocellulosic residues and obtain sugar or valuable products, but more work is needed in this direction. © 2017 The Society for Applied Microbiology.

  6. Ethanol production with dilute acid hydrolysis using partially dried lignocellulosics

    DOEpatents

    Nguyen, Quang A.; Keller, Fred A.; Tucker, Melvin P.

    2003-12-09

    A process of converting lignocellulosic biomass to ethanol, comprising hydrolyzing lignocellulosic materials by subjecting dried lignocellulosic material in a reactor to a catalyst comprised of a dilute solution of a strong acid and a metal salt to lower the activation energy (i.e., the temperature) of cellulose hydrolysis and ultimately obtain higher sugar yields.

  7. Utilization of lignocellulosic polysaccharides

    NASA Astrophysics Data System (ADS)

    Fenske, John James

    Lignocellulosic biomass represents a vast supply of fermentable carbohydrates and functional aromatic compounds. Conversion of lignocellulosics to ethanol and other useful products would be of widespread economical and environmental benefit. Better understanding of the behavior of different lignocellulosic feedstocks in fermentation protocols as well as catalytic activities involved in lignocellulosic depolymerization will further enhance the commercial viability of biomass-to-ethanol conversion processes. The relative toxicity of the combined non-xylose components in prehydrolysates derived from three different lignocellulosic biomass feedstocks (poplar, corn stover and switchgrass, or Panicum virgatum L.) was determined using a Pichia stipits fermentation assay. The relative toxicity of the prehydrolysates, in decreasing order, was poplar-derived prehydrolysates > switchgrass-derived prehydrolysates > corn stover-derived prehydrolysates. Ethanol yields averaged 74%, 83% and 88% of control values for poplar, switchgrass and corn stover prehydrolysates, respectively. Volumetric ethanol productivities (g ethanol lsp{-1} hsp{-1}) averaged 32%, 70% and 102% of control values for poplar, switchgrass and corn stover prehydrolysates, respectively. Ethanol productivities correlated closely with acetate concentrations in the prehydrolysates; however, regression lines correlating acetate concentrations and ethanol productivities were found to be feedstock-dependent. Differences in the relative toxicity of xylose-rich prehydrolysates derived from woody and herbaceous feedstocks are likely due to the relative abundance of a variety of inhibitory compounds, e.g. acetate and aromatic compounds. Fourteen aromatic monomers present in prehydrolysates prepared from corn stover, switchgrass, and poplar were tentatively identified by comparison with published mass spectra. The concentrations of the aromatic monomers totaled 112, 141 and 247 mg(l)sp{-1} for corn stover, switchgrass

  8. Evaluation of carbohydrates and lignocellulosic biomass from different wood species as raw material for the synthesis of 5-bromomethyfurfural.

    PubMed

    Bredihhin, Aleksei; Mäeorg, Uno; Vares, Lauri

    2013-06-28

    The influence of different parameters on the conversion of carbohydrates and biomass into the potential biofuel intermediate 5-bromomethylfurfural (BMF) has been studied. Our optimized conditions avoid the use of lithium salt additives, making this method cheaper and environmentally more benign compared to previously reported methods. Different wood species and their potential as a raw material in BMF and furfural production have also been evaluated. In addition, we report a very simple and efficient procedure for conversion of 5-hydroxymethylfurfural (HMF) into BMF or 5-chloromethylfurfural (CMF).

  9. Process Design and Economics for Conversion of Lignocellulosic Biomass to Ethanol: Thermochemical Pathway by Indirect Gasification and Mixed Alcohol Synthesis

    SciTech Connect

    Dutta, A.; Talmadge, M.; Hensley, J.; Worley, M.; Dudgeon, D.; Barton, D.; Groendijk, P.; Ferrari, D.; Stears, B.; Searcy, E. M.; Wright, C. T.; Hess, J. R.

    2011-05-01

    This design report describes an up-to-date benchmark thermochemical conversion process that incorporates the latest research from NREL and other sources. Building on a design report published in 2007, NREL and its subcontractor Harris Group Inc. performed a complete review of the process design and economic model for a biomass-to-ethanol process via indirect gasification. The conceptual design presented herein considers the economics of ethanol production, assuming the achievement of internal research targets for 2012 and nth-plant costs and financing. The design features a processing capacity of 2,205 U.S. tons (2,000 metric tonnes) of dry biomass per day and an ethanol yield of 83.8 gallons per dry U.S. ton of feedstock. The ethanol selling price corresponding to this design is $2.05 per gallon in 2007 dollars, assuming a 30-year plant life and 40% equity financing with a 10% internal rate of return and the remaining 60% debt financed at 8% interest. This ethanol selling price corresponds to a gasoline equivalent price of $3.11 per gallon based on the relative volumetric energy contents of ethanol and gasoline.

  10. A strain of Saccharomyces cerevisiae evolved for fermentation of lignocellulosic biomass displays improved growth and fermentative ability in high solids concentrations and in the presence of inhibitory compounds

    PubMed Central

    2011-01-01

    Background Softwoods are the dominant source of lignocellulosic biomass in the northern hemisphere, and have been investigated worldwide as a renewable substrate for cellulosic ethanol production. One challenge to using softwoods, which is particularly acute with pine, is that the pretreatment process produces inhibitory compounds detrimental to the growth and metabolic activity of fermenting organisms. To overcome the challenge of bioconversion in the presence of inhibitory compounds, especially at high solids loading, a strain of Saccharomyces cerevisiae was subjected to evolutionary engineering and adaptation for fermentation of pretreated pine wood (Pinus taeda). Results An industrial strain of Saccharomyces, XR122N, was evolved using pretreated pine; the resulting daughter strain, AJP50, produced ethanol much more rapidly than its parent in fermentations of pretreated pine. Adaptation, by preculturing of the industrial yeast XR122N and the evolved strains in 7% dry weight per volume (w/v) pretreated pine solids prior to inoculation into higher solids concentrations, improved fermentation performance of all strains compared with direct inoculation into high solids. Growth comparisons between XR122N and AJP50 in model hydrolysate media containing inhibitory compounds found in pretreated biomass showed that AJP50 exited lag phase faster under all conditions tested. This was due, in part, to the ability of AJP50 to rapidly convert furfural and hydroxymethylfurfural to their less toxic alcohol derivatives, and to recover from reactive oxygen species damage more quickly than XR122N. Under industrially relevant conditions of 17.5% w/v pretreated pine solids loading, additional evolutionary engineering was required to decrease the pronounced lag phase. Using a combination of adaptation by inoculation first into a solids loading of 7% w/v for 24 hours, followed by a 10% v/v inoculum (approximately equivalent to 1 g/L dry cell weight) into 17.5% w/v solids, the final

  11. Direct ethanol fermentation from lignocellulosic biomass by Antarctic basidiomycetous yeast Mrakia blollopis under a low temperature condition.

    PubMed

    Tsuji, Masaharu; Goshima, Tetsuya; Matsushika, Akinori; Kudoh, Sakae; Hoshino, Tamotsu

    2013-10-01

    Antarctic basidiomycetous yeast Mrakia blollopis SK-4 has unique fermentability for various sugars under a low temperature condition. Hence, this yeast was used for ethanol fermentation from glucose and also for direct ethanol fermentation (DEF) from cellulosic biomass without/with Tween 80 at 10°C. Maximally, 48.2 g/l ethanol was formed from 12% (w/v) glucose. DEF converted filter paper, Japanese cedar and Eucalyptus to 12.2 g/l, 12.5 g/l and 7.2 g/l ethanol, respectively. In the presence of 1% (v/v) Tween 80, ethanol concentration increased by about 1.1-1.6-fold compared to that without Tween 80. This is the first report on DEF using cryophilic fungi under a low temperature condition. We consider that M. blollopis SK-4 has a good potential for ethanol fermentation in cold environments. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Lignocellulose degradation patterns, structural changes, and enzyme secretion by Inonotus obliquus on straw biomass under submerged fermentation.

    PubMed

    Xu, Xiangqun; Xu, Zhiqi; Shi, Song; Lin, Mengmeng

    2017-10-01

    This study examined the white rot fungus I. obliquus on the degradation of three types of straw biomass and the production of extracellular lignocellulolytic enzymes under submerged fermentation. The fungus process resulted in a highest lignin loss of 72%, 39%, and 47% in wheat straw, rice straw, and corn stover within 12days, respectively. In merely two days, the fungus selectively degraded wheat straw lignin by 37%, with only limited cellulose degradation (13%). Fourier transform infrared spectroscopy revealed that the fungus most effectively degraded the wheat straw lignin and rice straw crystalline cellulose. Scanning electronic microscopy showed the most pronounced structural changes in wheat straw. High activities of manganese peroxidase (159.0U/mL) and lignin peroxidase (123.4U/mL) were observed in wheat straw culture on Day 2 and 4, respectively. Rice straw was the best substrate to induce the production of cellulase and xylanase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Determination of porosity of lignocellulosic biomass before and after pretreatment by using Simons' stain and NMR techniques.

    PubMed

    Meng, Xianzhi; Foston, Marcus; Leisen, Johannes; DeMartini, Jaclyn; Wyman, Charles E; Ragauskas, Arthur J

    2013-09-01

    To further investigate the effect of dilute acid pretreatment (DAP) and steam explosion pretreatment (SE) on the change in cellulose accessibility, several techniques were applied including a Simons' stain (SS) technique along with several NMR methods (i.e., NMR cryoporometry, (1)H spin-lattice (T1) and (1)H spin-spin (T2) relaxometry, and diffusometry). These methods were utilized to probe biomass porosity and thus assess cellulose accessibility on untreated and pretreated Populus. In general, these techniques indicate that pretreated Populus has larger pore size distributions and specific surface area (SSA) when compared to an untreated sample. The SS method revealed that DAP is more effective than SE in terms of the SSA increase, and that DAP increases SSA as a function of pretreatment severity. Relaxometry and diffusion measurements also suggest pore expansion occurs primarily in the first 10 min of DAP.

  14. Evaluation of microwave-assisted pretreatment of lignocellulosic biomass immersed in alkaline glycerol for fermentable sugars production.

    PubMed

    Diaz, Ana Belen; Moretti, Marcia Maria de Souza; Bezerra-Bussoli, Carolina; Carreira Nunes, Christiane da Costa; Blandino, Ana; da Silva, Roberto; Gomes, Eleni

    2015-06-01

    A pretreatment with microwave irradiation was applied to enhance enzyme hydrolysis of corn straw and rice husk immersed in water, aqueous glycerol or alkaline glycerol. Native and pretreated solids underwent enzyme hydrolysis using the extract obtained from the fermentation of Myceliophthora heterothallica, comparing its efficiency with that of the commercial cellulose cocktail Celluclast®. The highest saccharification yields, for both corn straw and rice husk, were attained when biomass was pretreated in alkaline glycerol, method that has not been previously reported in literature. Moreover, FTIR, TG and SEM analysis revealed a more significant modification in the structure of corn straw subjected to this pretreatment. Highest global yields were attained with the crude enzyme extract, which might be the result of its content in a great variety of hydrolytic enzymes, as revealed zymogram analysis. Moreover, its hydrolysis efficiency can be improved by its supplementation with commercial β-glucosidase.

  15. Discovering the desirable alleles contributing to the lignocellulosic biomass traits in saccharum germplasm collections for energy cane improvement

    SciTech Connect

    Todd, James; Comstock, Jack C.

    2015-11-25

    of the cores and the World Collection are similar to each other genotypically and phenotypically, but the core that was selected using only genotypic data was significantly different phenotypically. This indicates that there is not enough association between the genotypic and phenotypic diversity as to select using only genotypic diversity and get the full phenotypic diversity. Core Collection: Creation and Phenotyping Methods: To evaluate this germplasm for breeding purposes, a representative diversity panel selected from the WCSRG of approximately 300 accessions was planted at Canal Point, FL in three replications. These accessions were measured for stalk height and stalk number multiple times throughout the growing season and Brix and fresh biomass during harvest in 2013 and, stalk height, stalk number, stalk diameter, internode length, Brix and fresh and dry biomass was determined in the ratoon crop harvest in 2014. Results: In correlations of multiple measurements, there were higher correlations for early measurements of stalk number and stalk height with harvest traits like Brix and fresh weight. Hybrids had higher fresh mass and Brix while Saccharum spontaneum had higher stalk number and dry mass. The heritability of hybrid mass traits was lower in the ratoon crop. According to the principal component analysis, the diversity panel was divided into two groups. One group had accessions with high stalk number and high dry biomass like S. spontaneum and the other groups contained accessions with higher Brix and fresh biomass like S. officinarum. Mass traits correlated with each other as expected but hybrids had lower correlations between fresh and dry mass. Stalk number and the mass traits correlated with each other except in S. spontaneum and hybrids in the first ratoon. There were 110 accessions not significantly different in Brix from the commercial sugarcane checks including 10 S. spontaneum accessions. There were 27 dry and 6 fresh mass accessions

  16. Comparative biochemical analysis during the anaerobic digestion of lignocellulosic biomass from six morphological parts of Williams Cavendish banana (Triploid Musa AAA group) plants.

    PubMed

    Kamdem, Irénée; Hiligsmann, Serge; Vanderghem, Caroline; Bilik, Igor; Paquot, Michel; Thonart, Philippe

    2013-12-01

    We studied banana lignocellulosic biomass (BALICEBIOM) that is abandoned after fruit harvesting, and assessed its biochemical methane potential, because of its potential as an energy source. We monitored biogas production from six morphological parts (MPs) of the "Williams Cavendish" banana cultivar using a modified operating procedure (KOP) using KOH. Volatile fatty acid (VFA) production was measured using high performance liquid chromatography. The bulbs, leaf sheaths, petioles-midribs, leaf blades, rachis stems, and floral stalks gave total biogas production of 256, 205, 198, 126, 253, and 221 ml g⁻¹ dry matter, respectively, and total biomethane production of 150, 141, 127, 98, 162, and 144 ml g⁻¹, respectively. The biogas production rates and yields depended on the biochemical composition of the BALICEBIOM and the ability of anaerobic microbes to access fermentable substrates. There were no significant differences between the biogas analysis results produced using KOP and gas chromatography. Acetate was the major VFA in all the MP sample culture media. The bioconversion yields for each MP were below 50 %, showing that these substrates were not fully biodegraded after 188 days. The estimated electricity that could be produced from biogas combustion after fermenting all of the BALICEBIOM produced annually by the Cameroon Development Corporation-Del Monte plantations for 188 days is approximately 10.5 × 10⁶ kW h (which would be worth 0.80-1.58 million euros in the current market). This bioenergy could serve the requirements of about 42,000 people in the region, although CH₄ productivity could be improved.

  17. A novel NADPH-dependent aldehyde reductase gene from Saccharomyces cerevisiae NRRL Y-12632 involved in the detoxification of aldehyde inhibitors derived from lignocellulosic biomass conversion.

    PubMed

    Liu, Z Lewis; Moon, Jaewoong

    2009-10-01

    Aldehyde inhibitors such as furfural, 5-hydroxymethylfurfural, anisaldehyde, benzaldehyde, cinnamaldehyde, and phenylaldehyde are commonly generated during lignocellulosic biomass conversion process for low-cost cellulosic ethanol production that interferes with subsequent microbial growth and fermentation. In situ detoxification of the aldehyde inhibitors is possible by the tolerant ethanologenic yeast that involves multiple genes including numerous functional reductases. In this study, we report a novel aldehyde reductase gene clone Y63 from ethanologenic yeast Saccharomyces cerevisiae NRRL Y12632, representing the uncharacterized ORF YGL157W, which demonstrated NADPH-dependent reduction activities toward at least 14 aldehyde substrates. The identity of gene clone Y63 is the same with YGL157W of SGD since a variation of only 35 nucleotides in genomic sequence and three amino acid residues were observed between the two that share the same length of 347 residues in size. As one among the highly induced genes, YGL157W of Y-12632 showed significantly high levels of transcript abundance in response to furfural and HMF challenges. Based on the deduced amino acid sequence and the most conserved functional motif analyses including closely related reductases from five other yeast species to this date, YGL157W was identified as a member of the subclass 'intermediate' of the SDR (short-chain dehydrogenase/reductase) superfamily with the following typical characteristics: the most conserved catalytic site to lie at Tyr(169)-X-X-X-Lys(173); an indispensable reduction catalytic triad at Ser(131), Tyr(169), and Lys(173), and an approved cofactor-binding motif at Gly(11)-X-X-Gly(14)-X-X-Ala(17) near the N-terminus. YGL039W, YDR541C, and YOL151W (GRE2) appeared to be the similar type of enzymes falling into the same category of the intermediate subfamily.

  18. Posidonia oceanica as a Renewable Lignocellulosic Biomass for the Synthesis of Cellulose Acetate and Glycidyl Methacrylate Grafted Cellulose

    PubMed Central

    Coletti, Alessia; Valerio, Antonio; Vismara, Elena

    2013-01-01

    High-grade cellulose (97% α-cellulose content) of 48% crystallinity index was extracted from the renewable marine biomass waste Posidonia oceanica using H2O2 and organic peracids following an environmentally friendly and chlorine-free process. This cellulose appeared as a new high-grade cellulose of waste origin quite similar to the high-grade cellulose extracted from more noble starting materials like wood and cotton linters. The benefits of α-cellulose recovery from P. oceanica were enhanced by its transformation into cellulose acetate CA and cellulose derivative GMA-C. Fully acetylated CA was prepared by conventional acetylation method and easily transformed into a transparent film. GMA-C with a molar substitution (MS) of 0.72 was produced by quenching Fenton’s reagent (H2O2/FeSO4) generated cellulose radicals with GMA. GMA grafting endowed high-grade cellulose from Posidonia with adsorption capability. GMA-C removes β-naphthol from water with an efficiency of 47%, as measured by UV-Vis spectroscopy. After hydrolysis of the glycidyl group to glycerol group, the modified GMA-C was able to remove p-nitrophenol from water with an efficiency of 92%, as measured by UV-Vis spectroscopy. α-cellulose and GMA-Cs from Posidonia waste can be considered as new materials of potential industrial and environmental interest. PMID:28809259

  19. Solid-state fermentation in multi-well plates to assess pretreatment efficiency of rot fungi on lignocellulose biomass

    PubMed Central

    Zhou, Simeng; Raouche, Sana; Grisel, Sacha; Navarro, David; Sigoillot, Jean-Claude; Herpoël-Gimbert, Isabelle

    2015-01-01

    The potential of fungal pretreatment to improve fermentable sugar yields from wheat straw or Miscanthus was investigated. We assessed 63 fungal strains including 53 white-rot and 10 brown-rot fungi belonging to the Basidiomycota phylum in an original 12 day small-scale solid-state fermentation (SSF) experiment using 24-well plates. This method offers the convenience of one-pot processing of samples from SSF to enzymatic hydrolysis. The comparison of the lignocellulolytic activity profiles of white-rot fungi and brown-rot fungi showed different behaviours. The hierarchical clustering according to glucose and reducing sugars released from each biomass after 72 h enzymatic hydrolysis splits the set of fungal strains into three groups: efficient, no-effect and detrimental-effect species. The efficient group contained 17 species belonging to seven white-rot genera and one brown-rot genus. The yield of sugar released increased significantly (max. 62%) compared with non-inoculated controls for both substrates. PMID:26249037

  20. Lignocellulose hydrolysis by multienzyme complexes

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass is the most abundant renewable resource on the planet. Converting this material into a usable fuel is a multi-step process, the rate-limiting step being enzymatic hydrolysis of organic polymers into monomeric sugars. While the substrate can be complex and require a multitud...

  1. Metabolic engineering of Zymomonas mobilis for 2,3-butanediol production from lignocellulosic biomass sugars

    SciTech Connect

    Yang, Shihui; Mohagheghi, Ali; Franden, Mary Ann; Chou, Yat -Chen; Chen, Xiaowen; Dowe, Nancy; Himmel, Michael E.; Zhang, Min

    2016-09-02

    To develop pathways for advanced biofuel production, and to understand the impact of host metabolism and environmental conditions on heterologous pathway engineering for economic advanced biofuels production from biomass, we seek to redirect the carbon flow of the model ethanologen Zymomonas mobilis to produce desirable hydrocarbon intermediate 2,3-butanediol (2,3-BDO). 2,3-BDO is a bulk chemical building block, and can be upgraded in high yields to gasoline, diesel, and jet fuel. 2,3-BDO biosynthesis pathways from various bacterial species were examined, which include three genes encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase. Bioinformatics analysis was carried out to pinpoint potential bottlenecks for high 2,3-BDO production. Different combinations of 2,3-BDO biosynthesis metabolic pathways using genes from different bacterial species have been constructed. Our results demonstrated that carbon flux can be deviated from ethanol production into 2,3-BDO biosynthesis, and all three heterologous genes are essential to efficiently redirect pyruvate from ethanol production for high 2,3-BDO production in Z. mobilis. The down-selection of best gene combinations up to now enabled Z. mobilis to reach the 2,3-BDO production of more than 10 g/L from glucose and xylose, as well as mixed C6/C5 sugar streams derived from the deacetylation and mechanical refining process. In conclusion, this study confirms the value of integrating bioinformatics analysis and systems biology data during metabolic engineering endeavors, provides guidance for value-added chemical production in Z. mobilis, and reveals the interactions between host metabolism, oxygen levels, and a heterologous 2,3-BDO biosynthesis pathway. Taken together, this work provides guidance for future metabolic engineering efforts aimed at boosting 2,3-BDO titer anaerobically.

  2. Utilization of biomass in the U.S. for the production of ethanol fuel as a gasoline replacement. I - Terrestrial resource potential. II - Energy requirements, with emphasis on lignocellulosic conversion

    NASA Astrophysics Data System (ADS)

    Ferchak, J. D.; Pye, E. K.

    The paper assesses the biomass resource represented by starch derived from feed corn, surplus and distressed grain, and high-yield sugar crops planted on set-aside land in the U.S. It is determined that the quantity of ethanol produced may be sufficient to replace between 5 to 27% of present gasoline requirements. Utilization of novel cellulose conversion technology may in addition provide fermentable sugars from municipal, agricultural and forest wastes, and ultimately from highly productive silvicultural operations. The potential additional yield of ethanol from lignocellulosic biomass appears to be well in excess of liquid fuel requirements of an enhanced-efficiency transport sector at present mileage demands. No conflict with food production would be entailed. A net-energy assessment is made for lignocellulosic biomass feedstocks' conversion to ethanol and an almost 10:1 energy yield/energy cost ratio determined. It is also found that novel cellulose pretreatment and enzymatic conversion methods still under development may significantly improve even that figure, and that both chemical-feedstocks and energy-yielding byproducts such as carbon dioxide, biogas and lignin make ethanol production potentially energy self-sufficient. A final high-efficiency production approach incorporates site-optimized, nonpolluting energy sources such as solar and geothermal.

  3. Biohydrogen production from lignocellulosic feedstock.

    PubMed

    Cheng, Chieh-Lun; Lo, Yung-Chung; Lee, Kuo-Shing; Lee, Duu-Jong; Lin, Chiu-Yue; Chang, Jo-Shu

    2011-09-01

    Due to the recent energy crisis and rising concern over climate change, the development of clean alternative energy sources is of significant interest. Biohydrogen produced from cellulosic feedstock, such as second generation feedstock (lignocellulosic biomass) and third generation feedstock (carbohydrate-rich microalgae), is a promising candidate as a clean, CO2-neutral, non-polluting and high efficiency energy carrier to meet the future needs. This article reviews state-of-the-art technology on lignocellulosic biohydrogen production in terms of feedstock pretreatment, saccharification strategy, and fermentation technology. Future developments of integrated biohydrogen processes leading to efficient waste reduction, low CO2 emission and high overall hydrogen yield is discussed.

  4. Engineering Sugar Utilization and Microbial Tolerance toward Lignocellulose Conversion.

    PubMed

    Nieves, Lizbeth M; Panyon, Larry A; Wang, Xuan

    2015-01-01

    Production of fuels and chemicals through a fermentation-based manufacturing process that uses renewable feedstock such as lignocellulosic biomass is a desirable alternative to petrochemicals. Although it is still in its infancy, synthetic biology offers great potential to overcome the challenges associated with lignocellulose conversion. In this review, we will summarize the identification and optimization of synthetic biological parts used to enhance the utilization of lignocellulose-derived sugars and to increase the biocatalyst tolerance for lignocellulose-derived fermentation inhibitors. We will also discuss the ongoing efforts and future applications of synthetic integrated biological systems used to improve lignocellulose conversion.

  5. Engineering Sugar Utilization and Microbial Tolerance toward Lignocellulose Conversion

    PubMed Central

    Nieves, Lizbeth M.; Panyon, Larry A.; Wang, Xuan

    2015-01-01

    Production of fuels and chemicals through a fermentation-based manufacturing process that uses renewable feedstock such as lignocellulosic biomass is a desirable alternative to petrochemicals. Although it is still in its infancy, synthetic biology offers great potential to overcome the challenges associated with lignocellulose conversion. In this review, we will summarize the identification and optimization of synthetic biological parts used to enhance the utilization of lignocellulose-derived sugars and to increase the biocatalyst tolerance for lignocellulose-derived fermentation inhibitors. We will also discuss the ongoing efforts and future applications of synthetic integrated biological systems used to improve lignocellulose conversion. PMID:25741507

  6. Semi-continuous production of high-activity pectinases by immobilized Rhizopus oryzae using tobacco wastewater as substrate and their utilization in the hydrolysis of pectin-containing lignocellulosic biomass at high solid content.

    PubMed

    Zheng, Yu-Xi; Wang, Yuan-Liang; Pan, Jun; Zhang, Jian-Rong; Dai, Ya; Chen, Kun-Yan

    2017-10-01

    In this study, highly reactive endo- and exo-polygalacturonases (PGs) were produced from the tobacco industry wastewater using immobilized Rhizopus oryzae. Compared with free cells, immobilized cells increased enzyme activity 2.8-fold and reduced production time to 24h by shake-flask production. Moreover, the immobilized cells enabled the semi-continuous production of enzymes through repeated-batch mode for seven consecutive cycles in a scale-up bioreactor. During the first five cycles, the average endo-PG and exo-PG activities reached 307.5 and 242.6U/ml, respectively. The addition of crude enzyme for the hydrolysis of pectin-containing lignocellulosic biomass under high-gravity conditions increased glucose release 4.2-fold (115.4 vs. 29.0g/L), compared with hydrolysis using cellulase alone. This process achieves the efficient production of pectin-degrading enzymes, provides a cost-effective method for tobacco wastewater treatment, and offers the possibility to obtain fermentable sugars with high-titer from pectin-containing lignocellulosic biomass, which has important potential for the commercial production of bio-fuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Estimating the spatial distribution, extent and potential lignocellulosic biomass supply of Trees Outside Forests in Baden-Wuerttemberg using airborne LiDAR and OpenStreetMap data

    NASA Astrophysics Data System (ADS)

    Maack, Joachim; Lingenfelder, Marcus; Eilers, Christina; Smaltschinski, Thomas; Weinacker, Holger; Jaeger, Dirk; Koch, Barbara

    2017-06-01

    Trees Outside Forests (TOF) represent a source of lignocellulosic biomass that has received increasing attention in the recent years. While some studies have already investigated the potential of TOF in Germany, a spatial explicit analysis, specifically for Baden-Wuerttemberg, is still lacking. We used a unique wall-to-wall airborne Light Detection and Ranging (LiDAR) dataset combined with OpenStreetMap (OSM) data to map and classify TOF of the federal state of Baden-Wuerttemberg (∼35.000 km2) in south-western Germany. Furthermore, from annual biomass potentials of TOF areas collected from available literature, we calculated the mean annual biomass supply for all TOF areas in Baden-Wuerttemberg. This combination of remote sensing-based classification and available literature resulted in a mean annual biomass supply between ∼490,000-730,000 t from TOF in Baden-Wuerttemberg. The classification congruence on three reference sites was very high (∼99%) using a simple filter technique applied to the LiDAR data and masking man-made objects using OSM data. In contrast, the available literature revealed a high variability of biomass potentials, supporting the demand for an inventory system. Still, the results demonstrate the applicability of LiDAR based vegetation mapping and the value of OSM data in Baden-Wuerttemberg to detect man-made objects.

  8. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons via Indirect Liquefaction. Thermochemical Research Pathway to High-Octane Gasoline Blendstock Through Methanol/Dimethyl Ether Intermediates

    SciTech Connect

    Tan, Eric C. D.; Talmadge, Michael; Dutta, Abhijit; Hensley, Jesse; Schaidle, Josh; Biddy, Mary; Humbird, David; Snowden-Swan, Lesley J.; Ross, Jeff; Sexton, Danielle; Yap, Raymond; Lukas, John

    2015-03-01

    This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s (BETO’s) efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from lignocellulosic biomass feedstocks. The research funded by BETO is designed to advance the state of technology of biomass feedstock supply and logistics, conversion, and overall system sustainability. It is expected that these research improvements will be made within the 2022 timeframe. As part of their involvement in this research and development effort, the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory investigate the economics of conversion pathways through the development of conceptual biorefinery process models and techno-economic analysis models. This report describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas or syngas via indirect gasification, gas cleanup, catalytic conversion of syngas to methanol intermediate, methanol dehydration to dimethyl ether (DME), and catalytic conversion of DME to high-octane, gasoline-range hydrocarbon blendstock product. The conversion process configuration leverages technologies previously advanced by research funded by BETO and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via reforming of tars and other hydrocarbons is one of the key technology advancements realized as part of this prior research and 2012 demonstrations. The process described in this report evaluates a new technology area for the downstream utilization of clean biomass-derived syngas for the production of high-octane hydrocarbon products through methanol and DME intermediates. In this process, methanol undergoes dehydration to

  9. Grass Lignocellulose

    NASA Astrophysics Data System (ADS)

    Akin, Danny E.

    Grass lignocelluloses are limited in bioconversion by aromatic constituents, which include both lignins and phenolic acids esters. Histochemistry, ultraviolet absorption microspectrophotometry, and response to microorganisms and specific enzymes have been used to determine the significance of aromatics toward recalcitrance. Coniferyl lignin appears to be the most effective limitation to biodegradation, existing in xylem cells of vascular tissues; cell walls with syringyl lignin, for example, leaf sclerenchyma, are less recalcitrant. Esterified phenolic acids, i.e., ferulic and p-coumaric acids, often constitute a major chemical limitation in nonlignified cell walls to biodegradation in grasses, especially warm-season species. Methods to improve biodegradability through modification of aromatics include: plant breeding, use of lignin-degrading white-rot fungi, and addition of esterases. Plant breeding for new cultivars has been especially effective for nutritionally improved forages, for example, bermudagrasses. In laboratory studies, selective white-rot fungi that lack cellulases delignified the lignocellulosic materials and improved fermentation of residual carbohydrates. Phenolic acid esterases released p-coumaric and ferulic acids for potential coproducts, improved the available sugars for fermentation, and improved biodegradation. The separation and removal of the aromatic components for coproducts, while enhancing the availability of sugars for bioconversion, could improve the economics of bioconversion.

  10. The role of pretreatment in improving the enzymatic hydrolysis of lignocellulosic materials.

    PubMed

    Sun, Shaoni; Sun, Shaolong; Cao, Xuefei; Sun, Runcang

    2016-01-01

    Lignocellulosic materials are among the most promising alternative energy resources that can be utilized to produce cellulosic ethanol. However, the physical and chemical structure of lignocellulosic materials forms strong native recalcitrance and results in relatively low yield of ethanol from raw lignocellulosic materials. An appropriate pretreatment method is required to overcome this recalcitrance. For decades various pretreatment processes have been developed to improve the digestibility of lignocellulosic biomass. Each pretreatment process has a different specificity on altering the physical and chemical structure of lignocellulosic materials. In this paper, the chemical structure of lignocellulosic biomass and factors likely affect the digestibility of lignocellulosic materials are discussed, and then an overview about the most important pretreatment processes available are provided. In particular, the combined pretreatment strategies are reviewed for improving the enzymatic hydrolysis of lignocellulose and realizing the comprehensive utilization of lignocellulosic materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Degradation of phenolic compounds by the lignocellulose deconstructing thermoacidophilic bacterium Alicyclobacillus Acidocaldarius

    SciTech Connect

    Aston, John E.; Apel, William A.; Lee, Brady D.; Thompson, David N.; Lacey, Jeffrey A.; Newby, Deborah T.; Reed, David. W.; Thompson, Vicki S.

    2015-11-05

    Manuscript outlining degradation of phenolic compounds by Alicyclobacillus acidocaldarius. Work relates to degradation of lignocellulosic biomass, but has application to degradation of textile dyes and other environmental contamination.

  12. Pervaporation of ethanol from lignocellulosic fermentation broth.

    PubMed

    Gaykawad, Sushil S; Zha, Ying; Punt, Peter J; van Groenestijn, Johan W; van der Wielen, Luuk A M; Straathof, Adrie J J

    2013-02-01

    Pervaporation can be applied in ethanol production from lignocellulosic biomass. Hydrophobic pervaporation, using a commercial PDMS membrane, was employed to concentrate the ethanol produced by fermentation of lignocellulosic hydrolysate. To our knowledge, this is the first report describing this. Pervaporation carried out with three different lignocellulosic fermentation broths reduced the membrane performance by 17-20% as compared to a base case containing only 3 wt.% ethanol in water. The membrane fouling caused by these fermentation broths was irreversible. Solutions containing model lignocellulosic components were tested during pervaporation at the same conditions. A total flux decrease of 12-15%, as compared to the base case, was observed for each component except for furfural. Catechol was found to be most fouling component whereas furfural permeated through the membrane and increased the total flux. The membrane selectivity increased in the presence of fermentation broth but remained unchanged for all selected components.

  13. Process Design Report for Stover Feedstock: Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover

    SciTech Connect

    Aden, A.; Ruth, M.; Ibsen, K.; Jechura, J.; Neeves, K.; Sheehan, J.; Wallace, B.; Montague, L.; Slayton, A.; Lukas, J.

    2002-06-01

    The U.S. Department of Energy (DOE) is promoting the development of ethanol from lignocellulosic feedstocks as an alternative to conventional petroleum-based transportation fuels. DOE funds both fundamental and applied research in this area and needs a method for predicting cost benefits of many research proposals. To that end, the National Renewable Energy Laboratory (NREL) has modeled many potential process designs and estimated the economics of each process during the last 20 years. This report is an update of the ongoing process design and economic analyses at NREL.

  14. Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes.

    PubMed

    Bhalla, Aditya; Bansal, Namita; Kumar, Sudhir; Bischoff, Kenneth M; Sani, Rajesh K

    2013-01-01

    Second-generation feedstock, especially nonfood lignocellulosic biomass is a potential source for biofuel production. Cost-intensive physical, chemical, biological pretreatment operations and slow enzymatic hydrolysis make the overall process of lignocellulosic conversion into biofuels less economical than available fossil fuels. Lignocellulose conversions carried out at ≤ 50 °C have several limitations. Therefore, this review focuses on the importance of thermophilic bacteria and thermostable enzymes to overcome the limitations of existing lignocellulosic biomass conversion processes. The influence of high temperatures on various existing lignocellulose conversion processes and those that are under development, including separate hydrolysis and fermentation, simultaneous saccharification and fermentation, and extremophilic consolidated bioprocess are also discussed.

  15. Biomass

    Treesearch

    Bernard R. Parresol

    2001-01-01

    Biomass, the contraction for biological mass, is the amount of living material provided by a given area or volume of the earth's surface, whether terrestrial or aquatic. Biomass is important for commercial uses (e.g., fuel and fiber) and for national development planning, as well as for scientific studies of ecosystem productivity, energy and nutrient flows, and...

  16. Chemical modification of lignocellulosics

    Treesearch

    Roger M. Rowell

    1996-01-01

    Agro-based resources, also referrered to as lignocellulosics, are resources that contain cellulose, hemicelluloses, and lignin. Lignocellulosics include wood, agricultural residues, water plants, grasses, and other plant substances. When considering lignocellulosics as possible engineering materials, there are several very basic concepts that must be considered. First...

  17. Conditioning biomass for microbial growth

    DOEpatents

    Bodie, Elizabeth A; England, George

    2015-03-31

    The present invention relates to methods for improving the yield of microbial processes that use lignocellulose biomass as a nutrient source. The methods comprise conditioning a composition comprising lignocellulose biomass with an enzyme composition that comprises a phenol oxidizing enzyme. The conditioned composition can support a higher rate of growth of microorganisms in a process. In one embodiment, a laccase composition is used to condition lignocellulose biomass derived from non-woody plants, such as corn and sugar cane. The invention also encompasses methods for culturing microorganisms that are sensitive to inhibitory compounds in lignocellulose biomass. The invention further provides methods of making a product by culturing the production microorganisms in conditioned lignocellulose biomass.

  18. AtCesA8-driven OsSUS3 expression leads to largely enhanced biomass saccharification and lodging resistance by distinctively altering lignocellulose features in rice.

    PubMed

    Fan, Chunfen; Feng, Shengqiu; Huang, Jiangfeng; Wang, Yanting; Wu, Leiming; Li, Xukai; Wang, Lingqiang; Tu, Yuanyuan; Xia, Tao; Li, Jingyang; Cai, Xiwen; Peng, Liangcai

    2017-01-01

    Biomass recalcitrance and plant lodging are two complex traits that tightly associate with plant cell wall structure and features. Although genetic modification of plant cell walls can potentially reduce recalcitrance for enhancing biomass saccharification, it remains a challenge to maintain a normal growth with enhanced biomass yield and lodging resistance in transgenic plants. Sucrose synthase (SUS) is a key enzyme to regulate carbon partitioning by providing UDP-glucose as substrate for cellulose and other polysaccharide biosynthesis. Although SUS transgenic plants have reportedly exhibited improvement on the cellulose and starch based traits, little is yet reported about SUS impacts on both biomass saccharification and lodging resistance. In this study, we selected the transgenic rice plants that expressed OsSUS3 genes when driven by the AtCesA8 promoter specific for promoting secondary cell wall cellulose synthesis in Arabidopsis. We examined biomass saccharification and lodging resistance in the transgenic plants and detected their cell wall structures and wall polymer features. During two-year field experiments, the selected AtCesA8::SUS3 transgenic plants maintained a normal growth with slightly increased biomass yields. The four independent transgenic lines exhibited much higher biomass enzymatic saccharification and bioethanol production under chemical pretreatments at P < 0.01 levels, compared with the controls of rice cultivar and empty vector transgenic line. Notably, all transgenic lines showed a consistently enhanced lodging resistance with the increasing extension and pushing forces. Correlation analysis suggested that the reduced cellulose crystallinity was a major factor for largely enhanced biomass saccharification and lodging resistance in transgenic rice plants. In addition, the cell wall thickenings with the increased cellulose and hemicelluloses levels should also contribute to plant lodging resistance. Hence, this study has proposed a

  19. High-level hemicellulosic arabinose predominately affects lignocellulose crystallinity for genetically enhancing both plant lodging resistance and biomass enzymatic digestibility in rice mutants.

    PubMed

    Li, Fengcheng; Zhang, Mingliang; Guo, Kai; Hu, Zhen; Zhang, Ran; Feng, Yongqing; Yi, Xiaoyan; Zou, Weihua; Wang, Lingqiang; Wu, Changyin; Tian, Jinshan; Lu, Tiegang; Xie, Guosheng; Peng, Liangcai

    2015-05-01

    Rice is a major food crop with enormous biomass residue for biofuels. As plant cell wall recalcitrance basically decides a costly biomass process, genetic modification of plant cell walls has been regarded as a promising solution. However, due to structural complexity and functional diversity of plant cell walls, it becomes essential to identify the key factors of cell wall modifications that could not much alter plant growth, but cause an enhancement in biomass enzymatic digestibility. To address this issue, we performed systems biology analyses of a total of 36 distinct cell wall mutants of rice. As a result, cellulose crystallinity (CrI) was examined to be the key factor that negatively determines either the biomass enzymatic saccharification upon various chemical pretreatments or the plant lodging resistance, an integrated agronomic trait in plant growth and grain production. Notably, hemicellulosic arabinose (Ara) was detected to be the major factor that negatively affects cellulose CrI probably through its interlinking with β-1,4-glucans. In addition, lignin and G monomer also exhibited the positive impact on biomass digestion and lodging resistance. Further characterization of two elite mutants, Osfc17 and Osfc30, showing normal plant growth and high biomass enzymatic digestion in situ and in vitro, revealed the multiple GH9B candidate genes for reducing cellulose CrI and XAT genes for increasing hemicellulosic Ara level. Hence, the results have suggested the potential cell wall modifications for enhancing both biomass enzymatic digestibility and plant lodging resistance by synchronically overexpressing GH9B and XAT genes in rice.

  20. Investigation of adsorption kinetics and isotherm of cellulase and B-Glucosidase on lignocellulosic substrates

    USDA-ARS?s Scientific Manuscript database

    Clear understanding of enzyme adsorption during enzymatic hydrolysis of lignocellulosic biomass is essential to enhance the cost-efficiency of hydrolysis. However, conclusions from literatures often contradicted each other because enzyme adsorption is enzyme, biomass/pretreatment and experimental co...

  1. Genomic mechanisms of inhibitor-detoxification for low-cost lignocellulosic bioethanol conversion

    USDA-ARS?s Scientific Manuscript database

    One major challenges of sustainable lignocellulosic biomass conversion to ethanol is to overcome inhibitors generated from biomass pretreatment. Aldehyde inhibitors such as furfural, 5-hydroxymethylfurfural, cinnamaldehyde, phenylacetylaldehyde, and 4-hydroxybenzaldehyde, are common and potent inhi...

  2. Green methods of lignocellulose pretreatment for biorefinery development.

    PubMed

    Capolupo, Laura; Faraco, Vincenza

    2016-11-01

    Lignocellulosic biomass is the most abundant, low-cost, bio-renewable resource that holds enormous importance as alternative source for production of biofuels and other biochemicals that can be utilized as building blocks for production of new materials. Enzymatic hydrolysis is an essential step involved in the bioconversion of lignocellulose to produce fermentable monosaccharides. However, to allow the enzymatic hydrolysis, a pretreatment step is needed in order to remove the lignin barrier and break down the crystalline structure of cellulose. The present manuscript is dedicated to reviewing the most commonly applied "green" pretreatment processes used in bioconversion of lignocellulosic biomasses within the "biorefinery" concept. In this frame, the effects of different pretreatment methods on lignocellulosic biomass are described along with an in-depth discussion on the benefits and drawbacks of each method, including generation of potentially inhibitory compounds for enzymatic hydrolysis, effect on cellulose digestibility, and generation of compounds toxic for the environment, and energy and economic demand.

  3. First proof of concept of sustainable metabolite production from high solids fermentation of lignocellulosic biomass using a bacterial co-culture and cycling flush system.

    PubMed

    Yao, Wanying; Nokes, Sue E

    2014-12-01

    To improve the lignocellulose conversion for ABE in high solids fermentation, this study explored the feasibility of cycling the process through the cellulolytic or/and solventogenic phases via intermittent flushing of the fermentation media. Five different flushing strategies (varying medium ingredients, inoculum supplement and cycling through phases) were investigated. Flushing regularly throughout the cellulolytic phase is necessary because re-incubation at 65 °C significantly improved glucose availability by at least 6-fold. The solvents accumulation was increased by 4-fold using corn stover (3-fold using miscanthus) over that produced by flushing only through the solventogenic phase. In addition, cycling process was simplified by re-incubating the flushed cellulolytic phase with no re-inoculation because the initial inoculum of Clostridiumthermocellum remained viable throughout sequential co-culture. This study served as the first proof of the cycling flush system applied in co-cultural SSC and the knowledge gained can be used to design a farm-scale flushing system.

  4. The impact of furfural concentrations and substrate-to-biomass ratios on biological hydrogen production from synthetic lignocellulosic hydrolysate using mesophilic anaerobic digester sludge.

    PubMed

    Akobi, Chinaza; Hafez, Hisham; Nakhla, George

    2016-12-01

    This study evaluated the impact of furfural (a furan derivative) on hydrogen production rates and yields at initial substrate-to-microorganism ratios (S°/X°) of 4, 2, 1, and 0.5gCOD/gVSS and furfural concentrations of 4, 2, 1, and 0.5g/L. Fermentation studies were carried out in batches using synthetic lignocellulosic hydrolysate as substrate and mesophilic anaerobic digester sludge as seed. Contrary to other literature studies where furfural was inhibitory, this study showed that furfural concentrations of up to 1g/L enhanced hydrogen production with yields as high as 19% from the control (batch without furfural). Plots of hydrogen yields against gfurfural/gsugars and hydrogen yields versus gfurfural/gbiomass showed negative linear correlation indicating that these parameters influence biohydrogen production. Regression analysis indicated that gfurfural/gsugarsinitial exerted a greater effect on the degree of inhibition of hydrogen production than gfurfural/gVSSfinal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Semantic text mining support for lignocellulose research

    PubMed Central

    2012-01-01

    Background Biofuels produced from biomass are considered to be promising sustainable alternatives to fossil fuels. The conversion of lignocellulose into fermentable sugars for biofuels production requires the use of enzyme cocktails that can efficiently and economically hydrolyze lignocellulosic biomass. As many fungi naturally break down lignocellulose, the identification and characterization of the enzymes involved is a key challenge in the research and development of biomass-derived products and fuels. One approach to meeting this challenge is to mine the rapidly-expanding repertoire of microbial genomes for enzymes with the appropriate catalytic properties. Results Semantic technologies, including natural language processing, ontologies, semantic Web services and Web-based collaboration tools, promise to support users in handling complex data, thereby facilitating knowledge-intensive tasks. An ongoing challenge is to select the appropriate technologies and combine them in a coherent system that brings measurable improvements to the users. We present our ongoing development of a semantic infrastructure in support of genomics-based lignocellulose research. Part of this effort is the automated curation of knowledge from information on fungal enzymes that is available in the literature and genome resources. Conclusions Working closely with fungal biology researchers who manually curate the existing literature, we developed ontological natural language processing pipelines integrated in a Web-based interface to assist them in two main tasks: mining the literature for relevant knowledge, and at the same time providing rich and semantically linked information. PMID:22595090

  6. Semantic text mining support for lignocellulose research.

    PubMed

    Meurs, Marie-Jean; Murphy, Caitlin; Morgenstern, Ingo; Butler, Greg; Powlowski, Justin; Tsang, Adrian; Witte, René

    2012-04-30

    Biofuels produced from biomass are considered to be promising sustainable alternatives to fossil fuels. The conversion of lignocellulose into fermentable sugars for biofuels production requires the use of enzyme cocktails that can efficiently and economically hydrolyze lignocellulosic biomass. As many fungi naturally break down lignocellulose, the identification and characterization of the enzymes involved is a key challenge in the research and development of biomass-derived products and fuels. One approach to meeting this challenge is to mine the rapidly-expanding repertoire of microbial genomes for enzymes with the appropriate catalytic properties. Semantic technologies, including natural language processing, ontologies, semantic Web services and Web-based collaboration tools, promise to support users in handling complex data, thereby facilitating knowledge-intensive tasks. An ongoing challenge is to select the appropriate technologies and combine them in a coherent system that brings measurable improvements to the users. We present our ongoing development of a semantic infrastructure in support of genomics-based lignocellulose research. Part of this effort is the automated curation of knowledge from information on fungal enzymes that is available in the literature and genome resources. Working closely with fungal biology researchers who manually curate the existing literature, we developed ontological natural language processing pipelines integrated in a Web-based interface to assist them in two main tasks: mining the literature for relevant knowledge, and at the same time providing rich and semantically linked information.

  7. Ethanol production from lignocellulose

    DOEpatents

    Ingram, Lonnie O.; Wood, Brent E.

    2001-01-01

    This invention presents a method of improving enzymatic degradation of lignocellulose, as in the production of ethanol from lignocellulosic material, through the use of ultrasonic treatment. The invention shows that ultrasonic treatment reduces cellulase requirements by 1/3 to 1/2. With the cost of enzymes being a major problem in the cost-effective production of ethanol from lignocellulosic material, this invention presents a significant improvement over presently available methods.

  8. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels. Thermochemical Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors

    SciTech Connect

    Dutta, Abhijit; Sahir, Asad; Tan, Eric; Humbird, David; Snowden-Swan, Lesley J.; Meyer, Pimphan; Ross, Jeff; Sexton, Danielle; Yap, Raymond; Lukas, John Lukas

    2015-03-01

    This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructurecompatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis.

  9. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Fast Pyrolysis and Hydrotreating Bio-Oil Pathway

    SciTech Connect

    Jones, Susanne B.; Meyer, Pimphan A.; Snowden-Swan, Lesley J.; Padmaperuma, Asanga B.; Tan, Eric; Dutta, Abhijit; Jacobson, Jacob; Cafferty, Kara

    2013-11-01

    This report describes a proposed thermochemical process for converting biomass into liquid transportation fuels via fast pyrolysis followed by hydroprocessing of the condensed pyrolysis oil. As such, the analysis does not reflect the current state of commercially-available technology but includes advancements that are likely, and targeted to be achieved by 2017. The purpose of this study is to quantify the economic impact of individual conversion targets to allow a focused effort towards achieving cost reductions.

  10. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Fast Pyrolysis and Hydrotreating Bio-oil Pathway

    SciTech Connect

    Jones, S.; Meyer, P.; Snowden-Swan, L.; Padmaperuma, A.; Tan, E.; Dutta, A.; Jacobson, J.; Cafferty, K.

    2013-11-01

    This report describes a proposed thermochemical process for converting biomass into liquid transportation fuels via fast pyrolysis followed by hydroprocessing of the condensed pyrolysis oil. As such, the analysis does not reflect the current state of commercially-available technology but includes advancements that are likely, and targeted to be achieved by 2017. The purpose of this study is to quantify the economic impact of individual conversion targets to allow a focused effort towards achieving cost reductions.

  11. Process Design Report for Wood Feedstock: Lignocellulosic Biomass to Ethanol Process Desing and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios

    SciTech Connect

    Wooley, Robert; Ruth, Mark; Sheehan, John; Ibsen, Kelly; Majdeski, Henry; Galves, Adrian

    1999-07-01

    The National Renewable Energy Laboratory (NREL) has undertaken a complete review and update of the process design and economic model for the biomass-to-ethanol process based on co-current dilute acid prehydrolysis, along with simultaneous saccharification (enzymatic) and co-fermentation. The process design includes the core technologies being researched by the U.S. Department of Energy (DOE): prehydrolysis, simultaneous saccharification and co-fermentation, and cellulase enzyme production.

  12. The impacts of pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid pretreatment

    PubMed Central

    2009-01-01

    Background Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. Results Comparative evaluation on these two pretreatments reveal that (i) AFEX-pretreated corn stover is significantly more fermentable with respect to cell growth and sugar consumption, (ii) both pretreatments can achieve more than 80% of total sugar yield in the enzymatic hydrolysis of washed pretreated solids, and (iii) while AFEX completely preserves plant carbohydrates, dilute acid pretreatment at 5% solids loading degrades 13% of xylose to byproducts. Conclusion The selection of pretreatment will determine the biomass-processing configuration, requirements for hydrolysate conditioning (if any) and fermentation strategy. Through dilute acid pretreatment, the need for hemicellulase in biomass processing is negligible. AFEX-centered cellulosic technology can alleviate fermentation costs through reducing inoculum size and practically eliminating nutrient costs during bioconversion. However, AFEX requires supplemental xylanases as well as cellulase activity. As for long-term sustainability, AFEX has greater potential to diversify products from a cellulosic biorefinery due to lower levels of inhibitor generation and lignin loss. PMID:19961578

  13. The impacts of pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid pretreatment.

    PubMed

    Lau, Ming W; Gunawan, Christa; Dale, Bruce E

    2009-12-04

    Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. Comparative evaluation on these two pretreatments reveal that (i) AFEX-pretreated corn stover is significantly more fermentable with respect to cell growth and sugar consumption, (ii) both pretreatments can achieve more than 80% of total sugar yield in the enzymatic hydrolysis of washed pretreated solids, and (iii) while AFEX completely preserves plant carbohydrates, dilute acid pretreatment at 5% solids loading degrades 13% of xylose to byproducts. The selection of pretreatment will determine the biomass-processing configuration, requirements for hydrolysate conditioning (if any) and fermentation strategy. Through dilute acid pretreatment, the need for hemicellulase in biomass processing is negligible. AFEX-centered cellulosic technology can alleviate fermentation costs through reducing inoculum size and practically eliminating nutrient costs during bioconversion. However, AFEX requires supplemental xylanases as well as cellulase activity. As for long-term sustainability, AFEX has greater potential to diversify products from a cellulosic biorefinery due to lower levels of inhibitor generation and lignin loss.

  14. Genetic Determinants for Enzymatic Digestion of Lignocellulosic Biomass Are Independent of Those for Lignin Abundance in a Maize Recombinant Inbred Population

    DOE PAGES

    Penning, Bryan W.; Sykes, Robert W.; Babcock, Nicholas C.; ...

    2014-06-27

    Biotechnological approaches to reduce or modify lignin in biomass crops are predicated on the assumption that it is the principal determinant of the recalcitrance of biomass to enzymatic digestion for biofuels production. We defined quantitative trait loci (QTL) in the Intermated B73 x 3 Mo17 recombinant inbred maize (Zea mays) population using pyrolysis molecular-beam mass spectrometry to establish stem lignin content and an enzymatic hydrolysis assay to measure glucose and xylose yield. Among five multiyear QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yieldmore » was shared. A genome-wide association study for lignin abundance and sugar yield of the 282- member maize association panel provided candidate genes in the 11 QTL of the B73 and Mo17 parents but showed that many other alleles impacting these traits exist among this broader pool of maize genetic diversity. B73 and Mo17 genotypes exhibited large differences in gene expression in developing stem tissues independent of allelic variation. Combining these complementary genetic approaches provides a narrowed list of candidate genes. A cluster of SCARECROW-LIKE9 and SCARECROW-LIKE14 transcription factor genes provides exceptionally strong candidate genes emerging from the genome-wide association study. In addition to these and genes associated with cell wall metabolism, candidates include several other transcription factors associated with vascularization and fiber formation and components of cellular signaling pathways. Finally, these results provide new insights and strategies beyond the modification of lignin to enhance yields of biofuels from genetically modified biomass.« less

  15. Genetic Determinants for Enzymatic Digestion of Lignocellulosic Biomass Are Independent of Those for Lignin Abundance in a Maize Recombinant Inbred Population

    SciTech Connect

    Penning, Bryan W.; Sykes, Robert W.; Babcock, Nicholas C.; Dugard, Christopher K.; Held, Michael A.; Klimek, John F.; Shreve, Jacob T.; Fowler, Matthew; Ziebell, Angela; Davis, Mark F.; Decker, Stephen R.; Turner, Geoffrey B.; Mosier, Nathan S.; Springer, Nathan M.; Thimmapuram, Jyothi; Weil, Clifford F.; McCann, Maureen C.; Carpita, Nicholas C.

    2014-06-27

    Biotechnological approaches to reduce or modify lignin in biomass crops are predicated on the assumption that it is the principal determinant of the recalcitrance of biomass to enzymatic digestion for biofuels production. We defined quantitative trait loci (QTL) in the Intermated B73 x 3 Mo17 recombinant inbred maize (Zea mays) population using pyrolysis molecular-beam mass spectrometry to establish stem lignin content and an enzymatic hydrolysis assay to measure glucose and xylose yield. Among five multiyear QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yield was shared. A genome-wide association study for lignin abundance and sugar yield of the 282- member maize association panel provided candidate genes in the 11 QTL of the B73 and Mo17 parents but showed that many other alleles impacting these traits exist among this broader pool of maize genetic diversity. B73 and Mo17 genotypes exhibited large differences in gene expression in developing stem tissues independent of allelic variation. Combining these complementary genetic approaches provides a narrowed list of candidate genes. A cluster of SCARECROW-LIKE9 and SCARECROW-LIKE14 transcription factor genes provides exceptionally strong candidate genes emerging from the genome-wide association study. In addition to these and genes associated with cell wall metabolism, candidates include several other transcription factors associated with vascularization and fiber formation and components of cellular signaling pathways. Finally, these results provide new insights and strategies beyond the modification of lignin to enhance yields of biofuels from genetically modified biomass.

  16. Genetic Determinants for Enzymatic Digestion of Lignocellulosic Biomass Are Independent of Those for Lignin Abundance in a Maize Recombinant Inbred Population.

    PubMed

    Penning, Bryan W; Sykes, Robert W; Babcock, Nicholas C; Dugard, Christopher K; Held, Michael A; Klimek, John F; Shreve, Jacob T; Fowler, Matthew; Ziebell, Angela; Davis, Mark F; Decker, Stephen R; Turner, Geoffrey B; Mosier, Nathan S; Springer, Nathan M; Thimmapuram, Jyothi; Weil, Clifford F; McCann, Maureen C; Carpita, Nicholas C

    2014-08-01

    Biotechnological approaches to reduce or modify lignin in biomass crops are predicated on the assumption that it is the principal determinant of the recalcitrance of biomass to enzymatic digestion for biofuels production. We defined quantitative trait loci (QTL) in the Intermated B73 × Mo17 recombinant inbred maize (Zea mays) population using pyrolysis molecular-beam mass spectrometry to establish stem lignin content and an enzymatic hydrolysis assay to measure glucose and xylose yield. Among five multiyear QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yield was shared. A genome-wide association study for lignin abundance and sugar yield of the 282-member maize association panel provided candidate genes in the 11 QTL of the B73 and Mo17 parents but showed that many other alleles impacting these traits exist among this broader pool of maize genetic diversity. B73 and Mo17 genotypes exhibited large differences in gene expression in developing stem tissues independent of allelic variation. Combining these complementary genetic approaches provides a narrowed list of candidate genes. A cluster of SCARECROW-LIKE9 and SCARECROW-LIKE14 transcription factor genes provides exceptionally strong candidate genes emerging from the genome-wide association study. In addition to these and genes associated with cell wall metabolism, candidates include several other transcription factors associated with vascularization and fiber formation and components of cellular signaling pathways. These results provide new insights and strategies beyond the modification of lignin to enhance yields of biofuels from genetically modified biomass. © 2014 American Society of Plant Biologists. All Rights Reserved.

  17. Kinetic and Modeling Investigation to Provide Design Guidelines for the NREL Dilute-Acid Process Aimed at Total Hydrolysis/Fractionation of Lignocellulosic Biomass: July 1998

    SciTech Connect

    Lee, Y. Y.; Iyer, P.; Xiang, Q.; Hayes, J.

    2004-08-01

    Following up on previous work, subcontractor investigated three aspects of using NREL ''pretreatment'' technology for total hydrolysis (cellulose as well as hemicellulose) of biomass. Whereas historic hydrolysis of biomass used either dilute acid or concentrated acid technology for hydrolysis of both hemicellulose and cellulose, NREL has been pursuing very dilute acid hydrolysis of hemicellulose followed by enzymatic hydrolysis of cellulose. NREL's countercurrent shrinking-bed reactor design for hemicellulose hydrolysis (pretreatment) has, however, shown promise for total hydrolysis. For the first task, subcontractor developed a mathematical model of the countercurrent shrinking bed reactor operation and, using yellow poplar sawdust as a feedstock, analyzed the effect of: initial solid feeding rate, temperature, acid concentration, acid flow rate, Peclet number (a measure of backmixing in liquid flow), and bed shrinking. For the second task, subcontractor used laboratory trials, with yellow poplar sawdust and 0.07 wt% sulfuric acid at various temperatures, to verify the hydrolysis of cellulose to glucose (desired) and decomposition of glucose (undesired) and determine appropriate parameters for use in kinetic models. Unlike cellulose and hemicellulose, lignins, the third major component of biomass, are not carbohydrates that can be broken down into component sugars. They are, however, aromatic complex amorphous phenolic polymers that can likely be converted into low-molecular weight compounds suitable for production of fuels and chemicals. Oxidative degradation is one pathway for such conversion and hydrogen peroxide would be an attractive reagent for this, as it would leave no residuals. For the third task, subcontractor reacted lignin with hydrogen peroxide under various conditions and analyzed the resulting product mix.

  18. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Thermochemical Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors

    SciTech Connect

    Dutta, Abhijit; Sahir, A. H.; Tan, Eric; Humbird, David; Snowden-Swan, Lesley J.; Meyer, Pimphan A.; Ross, Jeff; Sexton, Danielle; Yap, Raymond; Lukas, John

    2015-03-01

    This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis. Both the in situ and ex situ conceptual designs, using the underlying assumptions, project MFSPs of approximately $3.5/gallon gasoline equivalent (GGE). The performance assumptions for the ex situ process were more aggressive with higher distillate (diesel-range) products. This was based on an assumption that more favorable reaction chemistry (such as coupling) can be made possible in a separate reactor where, unlike in an in situ upgrading reactor, one does not have to deal with catalyst mixing with biomass char and ash, which pose challenges to catalyst performance and maintenance. Natural gas was used for hydrogen production, but only when off gases from the process was not sufficient to meet the needs; natural gas consumption is insignificant in both the in situ and ex situ base cases. Heat produced from the burning of char, coke, and off-gases allows for the production of surplus electricity which is sold to the grid allowing a reduction of approximately 5¢/GGE in the MFSP.

  19. Genetic Determinants for Enzymatic Digestion of Lignocellulosic Biomass Are Independent of Those for Lignin Abundance in a Maize Recombinant Inbred Population1[W][OPEN

    PubMed Central

    Penning, Bryan W.; Sykes, Robert W.; Babcock, Nicholas C.; Dugard, Christopher K.; Held, Michael A.; Klimek, John F.; Shreve, Jacob T.; Fowler, Matthew; Ziebell, Angela; Davis, Mark F.; Decker, Stephen R.; Turner, Geoffrey B.; Mosier, Nathan S.; Springer, Nathan M.; Thimmapuram, Jyothi; Weil, Clifford F.; McCann, Maureen C.; Carpita, Nicholas C.

    2014-01-01

    Biotechnological approaches to reduce or modify lignin in biomass crops are predicated on the assumption that it is the principal determinant of the recalcitrance of biomass to enzymatic digestion for biofuels production. We defined quantitative trait loci (QTL) in the Intermated B73 × Mo17 recombinant inbred maize (Zea mays) population using pyrolysis molecular-beam mass spectrometry to establish stem lignin content and an enzymatic hydrolysis assay to measure glucose and xylose yield. Among five multiyear QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yield was shared. A genome-wide association study for lignin abundance and sugar yield of the 282-member maize association panel provided candidate genes in the 11 QTL of the B73 and Mo17 parents but showed that many other alleles impacting these traits exist among this broader pool of maize genetic diversity. B73 and Mo17 genotypes exhibited large differences in gene expression in developing stem tissues independent of allelic variation. Combining these complementary genetic approaches provides a narrowed list of candidate genes. A cluster of SCARECROW-LIKE9 and SCARECROW-LIKE14 transcription factor genes provides exceptionally strong candidate genes emerging from the genome-wide association study. In addition to these and genes associated with cell wall metabolism, candidates include several other transcription factors associated with vascularization and fiber formation and components of cellular signaling pathways. These results provide new insights and strategies beyond the modification of lignin to enhance yields of biofuels from genetically modified biomass. PMID:24972714

  20. Analysis of the Effects of Compositional and Configurational Assumptions on Product Costs for the Thermochemical Conversion of Lignocellulosic Biomass to Mixed Alcohols -- FY 2007 Progress Report

    SciTech Connect

    Zhu, Yunhua; Gerber, Mark A.; Jones, Susanne B.; Stevens, Don J.

    2008-12-05

    The purpose of this study was to examine alternative biomass-to-ethanol conversion process assumptions and configuration options to determine their relative effects on overall process economics. A process-flow-sheet computer model was used to determine the heat and material balance for each configuration that was studied. The heat and material balance was then fed to a costing spreadsheet to determine the impact on the ethanol selling price. By examining a number of operational and configuration alternatives and comparing the results to the base flow sheet, alternatives having the greatest impact the performance and cost of the overall system were identified and used to make decisions on research priorities.

  1. Acetylation of woody lignocellulose: significance and regulation

    PubMed Central

    Pawar, Prashant Mohan-Anupama; Koutaniemi, Sanna; Tenkanen, Maija; Mellerowicz, Ewa J.

    2013-01-01

    Non-cellulosic cell wall polysaccharides constitute approximately one quarter of usable biomass for human exploitation. In contrast to cellulose, these components are usually substituted by O-acetyl groups, which affect their properties and interactions with other polymers, thus affecting their solubility and extractability. However, details of these interactions are still largely obscure. Moreover, polysaccharide hydrolysis to constituent monosaccharides is hampered by the presence of O-acetyl groups, necessitating either enzymatic (esterase) or chemical de-acetylation, increasing the costs and chemical consumption. Reduction of polysaccharide acetyl content in planta is a way to modify lignocellulose toward improved saccharification. In this review we: (1) summarize literature on lignocellulose acetylation in different tree species, (2) present data and current hypotheses concerning the role of O-acetylation in determining woody lignocellulose properties, (3) describe plant proteins involved in lignocellulose O-acetylation, (4) give examples of microbial enzymes capable to de-acetylate lignocellulose, and (5) discuss prospects for exploiting these enzymes in planta to modify xylan acetylation. PMID:23734153

  2. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, Robert W.; Kadam, Kiran L.; Hsu, Teh-An; Philippidis, George P.; Wyman, Charles E.

    1998-01-01

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions.

  3. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, Robert W.; Kadam, Kiran L.; Hsu, Teh-An; Philippidis, George P.; Wyman, Charles E.

    1996-01-01

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions.

  4. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, Robert W.; Kadam, Kiran L.; Hsu, Teh-An; Philippidis, George P.; Wyman, Charles E.

    1995-01-01

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions.

  5. Lignocellulose-degrading enzymes from termites and their symbiotic microbiota.

    PubMed

    Ni, Jinfeng; Tokuda, Gaku

    2013-11-01

    Lignocellulose-the dry matter of plants, or "plant biomass"-digestion is of increasing interest in organismal metabolism research, specifically the conversion of biomass into biofuels. Termites efficiently decompose lignocelluloses, and studies on lignocellulolytic systems may elucidate mechanisms of efficient lignocellulose degradation in termites as well as offer novel enzyme sources, findings which have significant potential industrial applications. Recent progress in metagenomic and metatranscriptomic research has illuminated the diversity of lignocellulolytic enzymes within the termite gut. Here, we review state-of-the-art research on lignocellulose-degrading systems in termites, specifically cellulases, xylanases, and lignin modification enzymes produced by termites and their symbiotic microbiota. We also discuss recent investigations into heterologous overexpression of lignocellulolytic enzymes from termites and their symbionts.

  6. Microbial lipid-based lignocellulosic biorefinery: feasibility and challenges.

    PubMed

    Jin, Mingjie; Slininger, Patricia J; Dien, Bruce S; Waghmode, Suresh; Moser, Bryan R; Orjuela, Andrea; Sousa, Leonardo da Costa; Balan, Venkatesh

    2015-01-01

    Although single-cell oil (SCO) has been studied for decades, lipid production from lignocellulosic biomass has received substantial attention only in recent years as biofuel research moves toward producing drop-in fuels. This review gives an overview of the feasibility and challenges that exist in realizing microbial lipid production from lignocellulosic biomass in a biorefinery. The aspects covered here include biorefinery technologies, the microbial oil market, oleaginous microbes, lipid accumulation metabolism, strain development, process configurations, lignocellulosic lipid production, technical hurdles, lipid recovery, and technoeconomics. The lignocellulosic SCO-based biorefinery will be feasible only if a combination of low- and high-value lipids are coproduced, while lignin and protein are upgraded to high-value products. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Development and validation of a fast high pressure liquid chromatography method for the analysis of lignocellulosic biomass hydrolysis and fermentation products.

    PubMed

    Scarlata, Christopher J; Hyman, Deborah A

    2010-04-02

    A simple, precise, and accurate 10-min high pressure liquid chromatography (HPLC) method was developed and validated for the analysis of organic acids, alcohols, and furans from processing biomass into renewable fuels. The method uses an H(+) form cation-exchange resin stationary phase that has a five-fold shorter analysis time versus that in the traditional method. The new method was used for the analysis of acetic acid, ethanol, 5-hydroxymethyl furfural, and furfural. Results were compared with a legacy method that has historically has been used to analyze the same compounds but with a 55 min run time. Linearity was acceptable on the new method with r(2)>0.999 for all compounds using refractive index detection. Limits of detection were between 0.003 and 0.03 g/L and limits of quantification were between 0.1 and 0.01 g/L. The relative standard deviations for precision were less than 0.4% and recoveries ranged from 92% to 114% for all compounds.

  8. Analysis of the Effects of Compositional and Configurational Assumptions on Product Costs for the Thermochemical Conversion of Lignocellulosic Biomass to Mixed Alcohols – FY 2007 Progress Report

    SciTech Connect

    Zhu, Yunhua; Gerber, Mark A.; Jones, Susanne B.; Stevens, Don J.

    2009-02-01

    The purpose of this study was to examine alternative biomass-to-ethanol conversion process assumptions and configuration options to determine their relative effects on overall process economics. A process-flow-sheet computer model was used to determine the heat and material balance for each configuration that was studied. The heat and material balance was then fed to a costing spreadsheet to determine the impact on the ethanol selling price. By examining a number of operational and configuration alternatives and comparing the results to the base flow sheet, alternatives having the greatest impact the performance and cost of the overall system were identified and used to make decisions on research priorities. This report, which was originally published in December 2008, has been revised primarily to correct information presented in Appendix B -- Base Case Flow Sheets and Model Results. The corrections to Appendix B include replacement of several pages in Table B.1 that duplicated previous pages of the table. Other changes were made in Appendix B to correct inconsistencies between stream labels presented in the tables and the stream labels in the figures.

  9. Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol: Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover

    SciTech Connect

    Humbird, D.; Davis, R.; Tao, L.; Kinchin, C.; Hsu, D.; Aden, A.; Schoen, P.; Lukas, J.; Olthof, B.; Worley, M.; Sexton, D.; Dudgeon, D.

    2011-03-01

    This report describes one potential biochemical ethanol conversion process, conceptually based upon core conversion and process integration research at NREL. The overarching process design converts corn stover to ethanol by dilute-acid pretreatment, enzymatic saccharification, and co-fermentation. Building on design reports published in 2002 and 1999, NREL, together with the subcontractor Harris Group Inc., performed a complete review of the process design and economic model for the biomass-to-ethanol process. This update reflects NREL's current vision of the biochemical ethanol process and includes the latest research in the conversion areas (pretreatment, conditioning, saccharification, and fermentation), optimizations in product recovery, and our latest understanding of the ethanol plant's back end (wastewater and utilities). The conceptual design presented here reports ethanol production economics as determined by 2012 conversion targets and 'nth-plant' project costs and financing. For the biorefinery described here, processing 2,205 dry ton/day at 76% theoretical ethanol yield (79 gal/dry ton), the ethanol selling price is $2.15/gal in 2007$.

  10. Fungal Bioconversion of Lignocellulosic Residues; Opportunities & Perspectives

    PubMed Central

    Dashtban, Mehdi; Schraft, Heidi; Qin, Wensheng

    2009-01-01

    The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and environmental issues such as global warming and air pollution. Bioconversion of biomass has significant advantages over other alternative energy strategies because biomass is the most abundant and also the most renewable biomaterial on our planet. Bioconversion of lignocellulosic residues is initiated primarily by microorganisms such as fungi and bacteria which are capable of degrading lignocellulolytic materials. Fungi such as Trichoderma reesei and Aspergillus niger produce large amounts of extracellular cellulolytic enzymes, whereas bacterial and a few anaerobic fungal strains mostly produce cellulolytic enzymes in a complex called cellulosome, which is associated with the cell wall. In filamentous fungi, cellulolytic enzymes including endoglucanases, cellobiohydrolases (exoglucanases) and β-glucosidases work efficiently on cellulolytic residues in a synergistic manner. In addition to cellulolytic/hemicellulolytic activities, higher fungi such as basidiomycetes (e.g. Phanerochaete chrysosporium) have unique oxidative systems which together with ligninolytic enzymes are responsible for lignocellulose degradation. This review gives an overview of different fungal lignocellulolytic enzymatic systems including extracellular and cellulosome-associated in aerobic and anaerobic fungi, respectively. In addition, oxidative lignocellulose-degradation mechanisms of higher fungi are discussed. Moreover, this paper reviews the current status of the technology for bioconversion of biomass by fungi, with focus on mutagenesis, co-culturing and heterologous gene expression attempts to improve fungal lignocellulolytic activities to create robust fungal strains. PMID:19774110

  11. Fungal bioconversion of lignocellulosic residues; opportunities & perspectives.

    PubMed

    Dashtban, Mehdi; Schraft, Heidi; Qin, Wensheng

    2009-09-04

    The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and environmental issues such as global warming and air pollution. Bioconversion of biomass has significant advantages over other alternative energy strategies because biomass is the most abundant and also the most renewable biomaterial on our planet. Bioconversion of lignocellulosic residues is initiated primarily by microorganisms such as fungi and bacteria which are capable of degrading lignocellulolytic materials. Fungi such as Trichoderma reesei and Aspergillus niger produce large amounts of extracellular cellulolytic enzymes, whereas bacterial and a few anaerobic fungal strains mostly produce cellulolytic enzymes in a complex called cellulosome, which is associated with the cell wall. In filamentous fungi, cellulolytic enzymes including endoglucanases, cellobiohydrolases (exoglucanases) and beta-glucosidases work efficiently on cellulolytic residues in a synergistic manner. In addition to cellulolytic/hemicellulolytic activities, higher fungi such as basidiomycetes (e.g. Phanerochaete chrysosporium) have unique oxidative systems which together with ligninolytic enzymes are responsible for lignocellulose degradation. This review gives an overview of different fungal lignocellulolytic enzymatic systems including extracellular and cellulosome-associated in aerobic and anaerobic fungi, respectively. In addition, oxidative lignocellulose-degradation mechanisms of higher fungi are discussed. Moreover, this paper reviews the current status of the technology for bioconversion of biomass by fungi, with focus on mutagenesis, co-culturing and heterologous gene expression attempts to improve fungal lignocellulolytic activities to create robust fungal strains.

  12. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

    SciTech Connect

    Davis, R.; Tao, L.; Tan, E. C. D.; Biddy, M. J.; Beckham, G. T.; Scarlata, C.; Jacobson, J.; Cafferty, K.; Ross, J.; Lukas, J.; Knorr, D.; Schoen, P.

    2013-10-01

    This report describes one potential conversion process to hydrocarbon products by way of biological conversion of lingnocellulosic-dervied sugars. The process design converts biomass to a hydrocarbon intermediate, a free fatty acid, using dilute-acid pretreatement, enzymatic saccharification, and bioconversion. Ancillary areas--feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combusion, and utilities--are also included in the design.

  13. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, R.W.; Kadam, K.L.; Hsu, T.A.; Philippidis, G.P.; Wyman, C.E.

    1996-04-02

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions. 7 figs.

  14. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, R.W.; Kadam, K.L.; Hsu, T.A.; Philippidis, G.P.; Wyman, C.E.

    1998-01-06

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions. 7 figs.

  15. Prehydrolysis of lignocellulose

    DOEpatents

    Torget, R.W.; Kadam, K.L.; Hsu, T.A.; Philippidis, G.P.; Wyman, C.E.

    1995-06-13

    The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions. 7 figs.

  16. 'Cradle-to-grave' assessment of existing lignocellulose pretreatment technologies.

    PubMed

    da Costa Sousa, Leonardo; Chundawat, Shishir P S; Balan, Venkatesh; Dale, Bruce E

    2009-06-01

    Pretreatment is considered to be a central unit process in a biorefinery to convert lignocellulosic biomass into fuels and chemicals, affecting all other operations in the process. A variety of technologies to pretreat lignocellulosic biomass are available today, which encompass a wide range of physical, chemical, and biological based processes. Among these, chemical based pretreatments are considered to be the most promising for future biorefineries. However, several key criteria regarding technical, economical, and environmental considerations should be critically analyzed when adapting these technologies for the nascent biorefinery industry. This review will discuss the most important pretreatment methods available today and will highlight key criteria for the development of a future ideal pretreatment.

  17. Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

    Treesearch

    ZJ Wang; TQ Lan; JY Zhu

    2013-01-01

    Nonspecific (nonproductive) binding (adsorption) of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) is a relatively new process, but demonstrated robust performance for sugar and biofuel...

  18. Reviving the carbohydrate economy via multi-product lignocellulose biorefineries.

    PubMed

    Zhang, Y-H Percival

    2008-05-01

    Before the industrial revolution, the global economy was largely based on living carbon from plants. Now the economy is mainly dependent on fossil fuels (dead carbon). Biomass is the only sustainable bioresource that can provide sufficient transportation fuels and renewable materials at the same time. Cellulosic ethanol production from less costly and most abundant lignocellulose is confronted with three main obstacles: (1) high processing costs (dollars /gallon of ethanol), (2) huge capital investment (dollars approximately 4-10/gallon of annual ethanol production capacity), and (3) a narrow margin between feedstock and product prices. Both lignocellulose fractionation technology and effective co-utilization of acetic acid, lignin and hemicellulose will be vital to the realization of profitable lignocellulose biorefineries, since co-product revenues would increase the margin up to 6.2-fold, where all purified lignocellulose co-components have higher selling prices (> approximately 1.0/kg) than ethanol ( approximately 0.5/kg of ethanol). Isolation of large amounts of lignocellulose components through lignocellulose fractionation would stimulate R&D in lignin and hemicellulose applications, as well as promote new markets for lignin- and hemicellulose-derivative products. Lignocellulose resource would be sufficient to replace significant fractionations (e.g., 30%) of transportation fuels through liquid biofuels, internal combustion engines in the short term, and would provide 100% transportation fuels by sugar-hydrogen-fuel cell systems in the long term.

  19. A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance.

    PubMed

    Wang, Mingyu; Han, Lijuan; Liu, Shasha; Zhao, Xuebing; Yang, Jinghua; Loh, Soh Kheang; Sun, Xiaomin; Zhang, Chenxi; Fang, Xu

    2015-09-01

    Renewable energy from lignocellulosic biomass has been deemed an alternative to depleting fossil fuels. In order to improve this technology, we aim to develop robust mathematical models for the enzymatic lignocellulose degradation process. By analyzing 96 groups of previously published and newly obtained lignocellulose saccharification results and fitting them to Weibull distribution, we discovered Weibull statistics can accurately predict lignocellulose saccharification data, regardless of the type of substrates, enzymes and saccharification conditions. A mathematical model for enzymatic lignocellulose degradation was subsequently constructed based on Weibull statistics. Further analysis of the mathematical structure of the model and experimental saccharification data showed the significance of the two parameters in this model. In particular, the λ value, defined the characteristic time, represents the overall performance of the saccharification system. This suggestion was further supported by statistical analysis of experimental saccharification data and analysis of the glucose production levels when λ and n values change. In conclusion, the constructed Weibull statistics-based model can accurately predict lignocellulose hydrolysis behavior and we can use the λ parameter to assess the overall performance of enzymatic lignocellulose degradation. Advantages and potential applications of the model and the λ value in saccharification performance assessment were discussed.

  20. Molecular mechanisms of yeast tolerance and in situ detoxification of lignocellulose hydrolysates

    USDA-ARS?s Scientific Manuscript database

    Pretreatment of lignocellulose biomass for biofuels production generates inhibitory compounds that interfere with microbial growth and subsequent fermentation. Remediation of the inhibitors by current physical, chemical, and biological abatement means is economically impractical and overcoming the i...

  1. Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Corredor, Deisy Y.

    The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis process. Up to 72% of hexose yield and 94% of pentose yield were obtained using "modified" steam explosion with 2% sulfuric acid at 140°C for 30 min and enzymatic hydrolysis with cellulase (15 FPU/g cellulose) and beta-glucosidase (50 CBU/g cellulose).

  2. Additives enhancing enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Rocha-Martín, Javier; Martinez-Bernal, Claudio; Pérez-Cobas, Yolanda; Reyes-Sosa, Francisco Manuel; García, Bruno Díez

    2017-11-01

    Linked to the development of cellulolytic enzyme cocktails from Myceliophthora thermophila, we studied the effect of different additives on the enzymatic hydrolysis yield. The hydrolysis of pretreated corn stover (PCS), sugar cane straw (PSCS) and microcrystalline cellulose (Avicel) was performed under industrial conditions using high solid loadings, limited mixing, and low enzyme dosages. The addition of polyethylene glycol (PEG4000) allowed to increase the glucose yields by 10%, 7.5%, and 32%, respectively in the three materials. PEG4000 did not have significant effect on the stability of the main individual enzymes but increased beta-glucosidase and endoglucanase activity by 20% and 60% respectively. Moreover, the presence of PEG4000 accelerated cellulase-catalyzed hydrolysis reducing up to 25% the liquefaction time. However, a preliminary economical assessment concludes that even with these improvements, a lower contribution of PEG4000 to the 2G bioethanol production costs would be needed to reach commercial feasibility. Copyright © 2017. Published by Elsevier Ltd.

  3. Feasibility of Bioethanol Production From Lignocellulosic Biomass

    NASA Astrophysics Data System (ADS)

    Aunina, Zane; Bazbauers, Gatis; Valters, Karlis

    2010-01-01

    The objective of the paper is to discuss the potential of cellulosic ethanol production processes and compare them, to find the most appropriate production method for Latvia's situation, to perform theoretical calculations and to determine the potential ethanol price. In addition, price forecasts for future cellulosic and grain ethanol are compared. A feasibility estimate to determine the price of cellulosic ethanol in Latvia, if production were started in 2010, was made. The grain and cellulosic ethanol price comparison (future forecast) was made through to the year 2018.

  4. Advancing lignocellulose bioconversion through direct assessment of enzyme action on insoluble substrates.

    PubMed

    Goacher, Robyn E; Selig, Michael J; Master, Emma R

    2014-06-01

    Microbial utilization of lignocellulose from plant cell walls is integral to carbon cycling on Earth. Correspondingly, secreted enzymes that initiate lignocellulose depolymerization serve a crucial step in the bioconversion of lignocellulosic biomass to fuels and chemicals. Genome and metagenome sequencing efforts that span the past decade reveal the diversity of enzymes that have evolved to transform lignocellulose from wood, herbaceous plants and grasses. Nevertheless, there are relatively few examples where 'omic' technologies have identified novel enzyme activities or combinations thereof that dramatically improve the economics of lignocellulose bioprocessing and utilization. A likely factor contributing to the discrepancy between sequence-based enzyme discovery and enzyme application is the common practice to screen enzyme candidates based on activity measurements using soluble model compounds. In this context, the development and application of imaging, physicochemical, and spectromicroscopic techniques that allow direct assessment of enzyme action on relevant lignocellulosic substrates is reviewed.

  5. Rheology of concentrated biomass

    NASA Astrophysics Data System (ADS)

    Samaniuk, J. R.; Wang, J.; Root, T. W.; Scott, C. T.; Klingenberg, D. J.

    2011-12-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained using torque rheometry agree with those obtained using other rheometric methods, but torque rheometry can be used at much larger solids concentration (weight fractions of insoluble solids greater than 0.2). Yield stresses decrease with severity of hydrolysis, decrease when water-soluble polymers are added (for nonhydrolyzed biomass), and increase with particle length. Experimental results are qualitatively consistent with those obtained from particle-level simulations.

  6. Microbial lipid based lignocellulosic biorefinery: feasibility and challenges

    USDA-ARS?s Scientific Manuscript database

    Although single cell oil (SCO) has been studied for decades, lipid production from lignocellulosic biomass has only received substantial attention in recent years as biofuel research moves toward producing drop-in fuels. This review article gives an overview of the feasibility and challenges that ex...

  7. Lignin Valorization through Catalytic Lignocellulose Fractionation: A Fundamental Platform for the Future Biorefinery.

    PubMed

    Galkin, Maxim V; Samec, Joseph S M

    2016-07-07

    Current processes for the fractionation of lignocellulosic biomass focus on the production of high-quality cellulosic fibers for paper, board, and viscose production. The other fractions that constitute a major part of lignocellulose are treated as waste or used for energy production. The transformation of lignocellulose beyond paper pulp to a commodity (e.g., fine chemicals, polymer precursors, and fuels) is the only feasible alternative to current refining of fossil fuels as a carbon feedstock. Inspired by this challenge, scientists and engineers have developed a plethora of methods for the valorization of biomass. However, most studies have focused on using one single purified component from lignocellulose that is not currently generated by the existing biomass fractionation processes. A lot of effort has been made to develop efficient methods for lignin depolymerization. The step to take this fundamental research to industrial applications is still a major challenge. This review covers an alternative approach, in which the lignin valorization is performed in concert with the pulping process. This enables the fractionation of all components of the lignocellulosic biomass into valorizable streams. Lignocellulose fractions obtained this way (e.g., lignin oil and glucose) can be utilized in a number of existing procedures. The review covers historic, current, and future perspectives, with respect to catalytic lignocellulose fractionation processes.

  8. Cellulose solvent- and organic solvent-based lignocellulose fractionation enabled efficient sugar release from a variety of lignocellulosic feedstocks.

    PubMed

    Sathitsuksanoh, Noppadon; Zhu, Zhiguang; Zhang, Y-H Percival

    2012-08-01

    Developing feedstock-independent biomass pretreatment would be vital to second generation biorefineries that would fully utilize diverse non-food lignocellulosic biomass resources, decrease transportation costs of low energy density feedstock, and conserve natural biodiversity. Cellulose solvent- and organic solvent-based lignocellulose fractionation (COSLIF) was applied to a variety of feedstocks, including Miscanthus, poplar, their mixture, bagasse, wheat straw, and rice straw. Although non-pretreated biomass samples exhibited a large variation in enzymatic digestibility, the COSLIF-pretreated biomass samples exhibited similar high enzymatic glucan digestibilities and fast hydrolysis rates. Glucan digestibilities of most pretreated feedstocks were ∼93% at five filter paper units per gram of glucan. The overall glucose and xylose yields for the Miscanthus:poplar mixture at a weight ratio of 1:2 were 93% and 85%, respectively. These results suggested that COSLIF could be regarded as a feedstock-independent pretreatment suitable for processing diverse feedstocks by adjusting pretreatment residence time only.

  9. Fungal biodegradation of lignocelluloses

    Treesearch

    Annele Hatakka; Kenneth E. Hammel

    2010-01-01

    Uncertainties in the basic structures of especially lignin but also other components in lignocellulose make fungal biodegradation studies a challenging task. The following properties are important in terms of microbial or enzymatic attack: (1) lignin polymers have compact structures that are insoluble in water and difficult to penetrate by microbes or enzymes, (2) the...

  10. Bioethanol from lignocellulosics: Status and perspectives in Canada.

    PubMed

    Mabee, W E; Saddler, J N

    2010-07-01

    Canada has invested significantly in the development of a domestic bioethanol industry, and it is expected that bioethanol from lignocellulosics will become more desirable to the industry as it expands. Development of the Canadian industry to date is described in this paper, as are examples of domestic research programs focused on both bioconversion and thermochemical conversion to generate biofuels from lignocellulosic biomass. The availability of lignocellulosic residues from agricultural and forestry operations, and the potential biofuel production associated with these residues, is described. The policy tools used to develop the domestic bioethanol industry are explored. A residue-based process could greatly extend the potential of the bioethanol industry in Canada. It is estimated that bioethanol production from residual lignocellulosic feedstocks could provide up to 50% of Canada's 2006 transportation fuel demand, given ideal conversion and full access to these feedstocks. Utilizing lignocellulosic biomass will extend the geographic range of the bioethanol industry, and increase the stability and security of this sector by reducing the impact of localized disruptions in supply. Use of disturbance crops could add 9% to this figure, but not in a sustainable fashion. If pursued aggressively, energy crops ultimately could contribute bioethanol at a volume double that of Canada's gasoline consumption in 2006. This would move Canada towards greater transportation fuel independence and a larger role in the export of bioethanol to the global market.

  11. Cultivation of algal biofilm using different lignocellulosic materials as carriers.

    PubMed

    Zhang, Qi; Liu, Cuixia; Li, Yubiao; Yu, Zhigang; Chen, Zhihua; Ye, Ting; Wang, Xun; Hu, Zhiquan; Liu, Shiming; Xiao, Bo; Jin, Shiping

    2017-01-01

    Algal biofilm technology is recently supposed to be a promising method to produce algal biomass as the feedstock for the production of biofuels. However, the carrier materials currently used to form algal biofilm are either difficult to be obtained at a low price or undurable. Commercialization of the biofilm technology for algal biomass production extremely requires new and inexpensive materials as biofilm carriers with high biomass production performances. Four types of lignocellulosic materials were investigated to evaluate their performance of acting as carriers for algal cells attachment and the relevant effects on the algal biomass production in this study. The cultivation of algal biofilm was processed in a self-designed flat plate photo-bioreactor. The biofilm production and chemical composition of the harvested biomass were determined. The surface physics properties of the materials were examined through a confocal laser-scanning microscopy. Algal biomass production varied significantly with the variation of the carriers (P < 0.05). All the lignocellulosic materials showed better performances in biofilm production than poly methyl methacrylate, and the application of pine sawdust as the carrier could gain the maximum biofilm productivity of 10.92 g m(-2) day(-1) after 16-day cultivation. In addition, 20.10-23.20% total lipid, 30.35-36.73% crude proteins, and 20.29-25.93% carbohydrate were achieved from the harvested biomasses. Biomass productivity increased linearly as the increase of surface roughness, and Wenzel's roughness factor of the tested materials, and surface roughness might significantly affect the biomass production through the size of surface morphology and the area of surface (P < 0.05). The results showed that lignocellulosic materials can be efficient carriers for low-cost cultivation of algal biofilm and the enhancement of biomass productivity.

  12. Evaluation of lignocellulosic wastes for production of edible mushrooms.

    PubMed

    Rani, P; Kalyani, N; Prathiba, K

    2008-12-01

    The degradation of lignocellulosic wastes such as paddy straw, sorghum stalk, and banana pseudostem was investigated during solid-state fermentation by edible mushrooms Pleurotus eous and Lentinus connotus. Biological efficiency of 55-65% was observed in paddy straw followed by sorghum stalk (45%) and banana pseudostem (33%) for both fungal species. The activity of extracellular enzymes, namely cellulase, polyphenol oxidase, and laccase, together with the content of cellulose, lignin, and phenols, was studied in spent substrates on seventh, 17th, and 27th days of spawning, and these values were used as indicators of the extent of lignocellulosic degradation by mushroom. Both the mushroom species proved to be efficient degraders of lignocellulosic biomass of paddy straw and sorghum stalk, and the extent of cellulose degradation was 63-72% of dry weight (d.w.), and lignin degradation was 23-30% of the d.w. In banana pseudostem, the extent of the degradation was observed to be only 15-22% of the d.w. for both lignin and cellulose. Preferential removal of cellulose during initial growth period and delayed degradation of lignin were observed in all three substrates. This is associated with decrease in activity of cellulase and polyphenol oxidase and increase in laccase activity with spawn aging in spent substrates. Thus, bioconversion of lignocellulosic biomass by P. eous and L. connotus offers a promising way to convert low-quality biomass into an improved human food.

  13. Bioconversion of Lignocellulose Materials

    PubMed Central

    Kanmani, P.; Balaji, P.

    2006-01-01

    One of the most economically viable processes for the bioconversion of many lignocellulosic waste is represented by white rot fungi. Phanerochaete chrysosporium is one of the important commercially cultivated fungi which exhibit varying abilities to utilize different lignocellulosic as growth substrate. Examination of the lignocellulolytic enzyme profiles of the two organisms Phanerochaete chrysosporium and Rhizopus stolonifer show this diversity to be reflected in qualitative variation in the major enzymatic determinants (ie cellulase, xylanase, ligninase and etc) required for substrate bioconversion. For example P. chrysosporium which is cultivated on highly lignified substrates such as wood (or) sawdust, produces two extracellular enzymes which have associated with lignin deploymerization. (Mn peroxidase and lignin peroxidase). Conversely Rhizopus stolonifer which prefers high cellulose and low lignin containg substrates produce a family of cellulolytic enzymes including at least cellobiohydrolases and β-glucosidases, but very low level of recognized lignin degrading enzymes. PMID:24039492

  14. Bioprocessing of bio-based chemicals produced from lignocellulosic feedstocks.

    PubMed

    Kawaguchi, Hideo; Hasunuma, Tomohisa; Ogino, Chiaki; Kondo, Akihiko

    2016-12-01

    The feedstocks used for the production of bio-based chemicals have recently expanded from edible sugars to inedible and more recalcitrant forms of lignocellulosic biomass. To produce bio-based chemicals from renewable polysaccharides, several bioprocessing approaches have been developed and include separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and consolidated bioprocessing (CBP). In the last decade, SHF, SSF, and CBP have been used to generate macromolecules and aliphatic and aromatic compounds that are capable of serving as sustainable, drop-in substitutes for petroleum-based chemicals. The present review focuses on recent progress in the bioprocessing of microbially produced chemicals from renewable feedstocks, including starch and lignocellulosic biomass. In particular, the technological feasibility of bio-based chemical production is discussed in terms of the feedstocks and different bioprocessing approaches, including the consolidation of enzyme production, enzymatic hydrolysis of biomass, and fermentation.

  15. Directed plant cell-wall accumulation of iron: embedding co-catalyst for efficient biomass conversion

    Treesearch

    Chien-Yuan Lin; Joseph E. Jakes; Bryon S. Donohoe; Peter N. Ciesielski; Haibing Yang; Sophie-Charlotte Gleber; Stefan Vogt; Shi-You Ding; Wendy A. Peer; Angus S. Murphy; Maureen C. McCann; Michael E. Himmel; Melvin P. Tucker; Hui Wei

    2016-01-01

    Background: Plant lignocellulosic biomass is an abundant, renewable feedstock for the production of biobased fuels and chemicals. Previously, we showed that iron can act as a co-catalyst to improve the deconstruction of lignocellulosic biomass. However, directly adding iron catalysts into biomass prior to pretreatment is diffusion limited,...

  16. Biomass conversion inhibitors and in situ detoxification

    USDA-ARS?s Scientific Manuscript database

    Inhibitory compounds derived from lignocellulosic biomass pretreatment are classified into aldehydes, ketones, organic acids, and phenols based on their chemical functional group that are toxic to fermentative microorganisms. Inhibitors and effects of inhibition to fermentative microbes vary depend...

  17. Fungal degradation of lignocellulosic residues: an aspect of improved nutritive quality.

    PubMed

    Sharma, Rakesh Kumar; Arora, Daljit Singh

    2015-02-01

    Microbial degradation of lignocellulosic materials brings a variety of changes in their bio-physicochemical properties. Lower digestibility of various agricultural residues can be enhanced by microbial treatment. White rot fungi are the potential candidates, which can improve the nutritional quality of lignocellulosic residues by degrading lignin and converting complex polysaccharides into simple sugars. Changes in physical qualities of lignocellulosics that is texture, colour and aroma have been an interesting area of study along with chemical properties. Degradation of lignocellulose not only upgrades the quality of degraded biomass, but helps simultaneous production of different commercial enzymes and other by products of interest. The review is focused on fungal degradation of lignocellulosics, resultant changes in physicochemical properties and nutritional value.

  18. The Status of and key barriers in lignocellulosic ethanol production : a technological perspective

    Treesearch

    J.Y. Zhu; G.S. Wang; X.J. Pan; R. Gleisner

    2008-01-01

    The development of biorefineries to produce fuel ethanol and commodity chemicals from lignocellulosic biomass is a potential alternative to current reliance on non-renewable resources. However, many technological barriers remain despite research progress in the past several decades. This article examines the major process barriers in biochemical conversion of biomass...

  19. Modeling progression of fluorescent probes in bioinspired lignocellulosic assemblies.

    PubMed

    Paës, Gabriel; Burr, Sally; Saab, Marie-Belle; Molinari, Michaël; Aguié-Béghin, Véronique; Chabbert, Brigitte

    2013-07-08

    Progression of enzymes in lignocellulosic biomass is a crucial parameter in biorefinery processes, and it appears to be one of the limiting factors in optimizing lignocellulose degradation. In order to assay the importance of the chemical and structural features of the substrate matrix on enzyme mobility, we have designed bioinspired model assemblies of secondary plant cell walls, which have been used to measure the mobility of fluorescent probes while modifying different parameters (probe size, water content, polysaccharide concentration). The results were used to construct a model of probe mobility and to rank the parameters in order of importance. Water content and probe size were shown to have the greatest effect. Although these assemblies are simplified templates of the plant cell walls, our strategy paves the way for proposing new approaches for optimizing biomass saccharification, such as selecting enzymes with suitable properties.

  20. Biomass pretreatment: fundamentals toward application.

    PubMed

    Agbor, Valery B; Cicek, Nazim; Sparling, Richard; Berlin, Alex; Levin, David B

    2011-01-01

    Development of sustainable energy systems based on renewable biomass feedstocks is now a global effort. Lignocellulosic biomass contains polymers of cellulose, hemicellulose, and lignin, bound together in a complex structure. Liquid biofuels, such as ethanol, can be made from biomass via fermentation of sugars derived from the cellulose and hemicellulose within lignocellulosic materials, but the biomass must be subjected to pretreatment processes to liberate the sugars needed for fermentation. Production of value-added co-products along-side biofuels through integrated biorefinery processes creates the need for selectivity during pretreatment. This paper presents a survey of biomass pretreatment technologies with emphasis on concepts, mechanism of action and practicability. The advantages and disadvantages, and the potential for industrial applications of different pretreatment technologies are the highlights of this paper. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Proteins for breaking barriers in lignocellulosic bioethanol production.

    PubMed

    Ulaganathan, Kandasamy; Goud, Burragoni S; Reddy, Mettu M; Kumar, Vanaparthi P; Balsingh, Jatoth; Radhakrishna, Surabhi

    2015-01-01

    Reduction in fossil fuel consumption by using alternate sources of energy is a major challenge facing mankind in the coming decades. Bioethanol production using lignocellulosic biomass is the most viable option for addressing this challenge. Industrial bioconversion of lignocellulosic biomass, though possible now, is not economically viable due to presence of barriers that escalate the cost of production. As cellulose and hemicellulose are the major constituents of terrestrial biomass, which is available in massive quantities, hydrolysis of cellulose and hemicellulose by the microorganisms are the most prominent biochemical processes happening in the earth. Microorganisms possess different categories of proteins associated with different stages of bioethanol production and a number of them are already found and characterized. Many more of these proteins need to be identified which suit the specificities needed for the bioethanol production process. Discovery of proteins with novel specificities and application of genetic engineering technologies to harvest the synergies existing between them with the aim to develop consolidated bioprocess is the major direction of research in the future. In this review, we discuss the different categories of proteins used for bioethanol production in the context of breaking the barriers existing for the economically feasible lignocellulosic bioethanol production.

  2. Augmented digestion of lignocellulose by steam explosion, acid and alkaline pretreatment methods: a review.

    PubMed

    Singh, Joginder; Suhag, Meenakshi; Dhaka, Anil

    2015-03-06

    Lignocellulosic materials can be explored as one of the sustainable substrates for bioethanol production through microbial intervention as they are abundant, cheap and renewable. But at the same time, their recalcitrant structure makes the conversion process more cumbersome owing to their chemical composition which adversely affects the efficiency of bioethanol production. Therefore, the technical approaches to overcome recalcitrance of biomass feedstock has been developed to remove the barriers with the help of pretreatment methods which make cellulose more accessible to the hydrolytic enzymes, secreted by the microorganisms, for its conversion to glucose. Pretreatment of lignocellulosic biomass in cost effective manner is a major challenge to bioethanol technology research and development. Hence, in this review, we have discussed various aspects of three commonly used pretreatment methods, viz., steam explosion, acid and alkaline, applied on various lignocellulosic biomasses to augment their digestibility alongwith the challenges associated with their processing.

  3. Fermentation of lignocellulosic sugars to acetic acid by Moorella thermoacetica.

    PubMed

    Ehsanipour, Mandana; Suko, Azra Vajzovic; Bura, Renata

    2016-06-01

    A systematic study of bioconversion of lignocellulosic sugars to acetic acid by Moorella thermoacetica (strain ATCC 39073) was conducted. Four different water-soluble fractions (hydrolysates) obtained after steam pretreatment of lignocellulosic biomass were selected and fermented to acetic acid in batch fermentations. M. thermoacetica can effectively ferment xylose and glucose in hydrolysates from wheat straw, forest residues, switchgrass, and sugarcane straw to acetic acid. Xylose and glucose were completely utilized, with xylose being consumed first. M. thermoacetica consumed up to 62 % of arabinose, 49 % galactose and 66 % of mannose within 72 h of fermentation in the mixture of lignocellulosic sugars. The highest acetic acid yield was obtained from sugarcane straw hydrolysate, with 71 % of theoretical yield based on total sugars (17 g/L acetic acid from 24 g/L total sugars). The lowest acetic acid yield was observed in forest residues hydrolysate, with 39 % of theoretical yield based on total sugars (18 g/L acetic acid from 49 g/L total sugars). Process derived compounds from steam explosion pretreatment, including 5-hydroxymethylfurfural (0.4 g/L), furfural (0.1 g/L) and total phenolics (3 g/L), did not inhibit microbial growth and acetic acid production yield. This research identified two major factors that adversely affected acetic acid yield in all hydrolysates, especially in forest residues: (i) glucose to xylose ratio and (ii) incomplete consumption of arabinose, galactose and mannose. For efficient bioconversion of lignocellulosic sugars to acetic acid, it is imperative to have an appropriate balance of sugars in a hydrolysate. Hence, the choice of lignocellulosic biomass and steam pretreatment design are fundamental steps for the industrial application of this process.

  4. A review of biological delignification and detoxification methods for lignocellulosic bioethanol production.

    PubMed

    Moreno, Antonio D; Ibarra, David; Alvira, Pablo; Tomás-Pejó, Elia; Ballesteros, Mercedes

    2015-01-01

    Future biorefineries will integrate biomass conversion processes to produce fuels, power, heat and value-added chemicals. Due to its low price and wide distribution, lignocellulosic biomass is expected to play an important role toward this goal. Regarding renewable biofuel production, bioethanol from lignocellulosic feedstocks is considered the most feasible option for fossil fuels replacement since these raw materials do not compete with food or feed crops. In the overall process, lignin, the natural barrier of the lignocellulosic biomass, represents an important limiting factor in biomass digestibility. In order to reduce the recalcitrant structure of lignocellulose, biological pretreatments have been promoted as sustainable and environmentally friendly alternatives to traditional physico-chemical technologies, which are expensive and pollute the environment. These approaches include the use of diverse white-rot fungi and/or ligninolytic enzymes, which disrupt lignin polymers and facilitate the bioconversion of the sugar fraction into ethanol. As there is still no suitable biological pretreatment technology ready to scale up in an industrial context, white-rot fungi and/or ligninolytic enzymes have also been proposed to overcome, in a separated or in situ biodetoxification step, the effect of the inhibitors produced by non-biological pretreatments. The present work reviews the latest studies regarding the application of different microorganisms or enzymes as useful and environmentally friendly delignification and detoxification technologies for lignocellulosic biofuel production. This review also points out the main challenges and possible ways to make these technologies a reality for the bioethanol industry.

  5. Methods for treating lignocellulosic materials

    DOEpatents

    Jansen, Robert; Gregoire, Claire; Travisano, Philip; Madsen, Lee; Matis, Neta; Har-Tal, Yael Miriam; Eliahu, Shay; Lawson, James Alan; Lapidot, Noa; Eyal, Aharon M.; Bauer, Timothy Allen; McWilliams, Paul; Zviely, Michael; Carden, Adam

    2017-05-16

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  6. Methods for treating lignocellulosic materials

    DOEpatents

    Jansen, Robert; Gregoire, Claire; Travisano, Philip; Madsen, Lee; Matis, Neta; Har-Tal, Yael Miriam; Eliahu, Shay; Lawson, James Alan; Lapidot, Noa; Burke, Luke; Eyal, Aharon M.; Bauer, Timothy Allen; Sade, Hagit; McWilliams, Paul; Zviely, Michael; Carden, Adam

    2017-04-25

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  7. Methods for treating lignocellulosic materials

    DOEpatents

    Jansen, Robert; Gregoire, Claire; Travisano, Philip; Madsen, Lee; Matis, Neta; Har-Tal, Yael; Eliahu, Shay; Lawson, James Alan; Lapidot, Noa; Eyal, Aharon M.; Bauer, Timothy Allen; Sade, Hagit; McWilliams, Paul; Zviely, Michael; Carden, Adam

    2016-11-15

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  8. Methods for degrading lignocellulosic materials

    DOEpatents

    Vlasenko, Elena; Cherry, Joel; Xu, Feng

    2008-04-08

    The present invention relates to methods for degrading a lignocellulosic material, comprising: treating the lignocellulosic material with an effective amount of one or more cellulolytic enzymes in the presence of at least one surfactant selected from the group consisting of a secondary alcohol ethoxylate, fatty alcohol ethoxylate, nonylphenol ethoxylate, tridecyl ethoxylate, and polyoxyethylene ether, wherein the presence of the surfactant increases the degradation of lignocellulosic material compared to the absence of the surfactant. The present invention also relates to methods for producing an organic substance, comprising: (a) saccharifying a lignocellulosic material with an effective amount of one or more cellulolytic enzymes in the presence of at least one surfactant selected from the group consisting of a secondary alcohol ethoxylate, fatty alcohol ethoxylate, nonylphenol ethoxylate, tridecyl ethoxylate, and polyoxyethylene ether, wherein the presence of the surfactant increases the degradation of lignocellulosic material compared to the absence of the surfactant; (b) fermenting the saccharified lignocellulosic material of step (a) with one or more fermentating microoganisms; and (c) recovering the organic substance from the fermentation.

  9. Methods for degrading lignocellulosic materials

    DOEpatents

    Vlasenko, Elena; Cherry, Joel; Xu, Feng

    2011-05-17

    The present invention relates to methods for degrading a lignocellulosic material, comprising: treating the lignocellulosic material with an effective amount of one or more cellulolytic enzymes in the presence of at least one surfactant selected from the group consisting of a secondary alcohol ethoxylate, fatty alcohol ethoxylate, nonylphenol ethoxylate, tridecyl ethoxylate, and polyoxyethylene ether, wherein the presence of the surfactant increases the degradation of lignocellulosic material compared to the absence of the surfactant. The present invention also relates to methods for producing an organic substance, comprising: (a) saccharifying a lignocellulosic material with an effective amount of one or more cellulolytic enzymes in the presence of at least one surfactant selected from the group consisting of a secondary alcohol ethoxylate, fatty alcohol ethoxylate, nonylphenol ethoxylate, tridecyl ethoxylate, and polyoxyethylene ether, wherein the presence of the surfactant increases the degradation of lignocellulosic material compared to the absence of the surfactant; (b) fermenting the saccharified lignocellulosic material of step (a) with one or more fermenting microorganisms; and (c) recovering the organic substance from the fermentation.

  10. Ethanol production from woody biomass: Silvicultural opportunities for suppressed western conifers

    Treesearch

    Andrew Youngblood; Junyong Zhu; C. Tim. Scott

    2010-01-01

    The 2007 Energy Security and Independence Act (ESIA) requires 16 billion gallons of ethanol to be produced from lignocellulose biomass by 2022 in the United States. Forests can be a key source of renewable lignocellulose for ethanol production if cost and conversion efficiency barriers can be overcome. We explored opportunities for using woody biomass from thinning...

  11. Hyperthermophilic endoglucanase for in planta lignocellulose conversion

    PubMed Central

    2012-01-01

    Background The enzymatic conversion of lignocellulosic plant biomass into fermentable sugars is a crucial step in the sustainable and environmentally friendly production of biofuels. However, a major drawback of enzymes from mesophilic sources is their suboptimal activity under established pretreatment conditions, e.g. high temperatures, extreme pH values and high salt concentrations. Enzymes from extremophiles are better adapted to these conditions and could be produced by heterologous expression in microbes, or even directly in the plant biomass. Results Here we show that a cellulase gene (sso1354) isolated from the hyperthermophilic archaeon Sulfolobus solfataricus can be expressed in plants, and that the recombinant enzyme is biologically active and exhibits the same properties as the wild type form. Since the enzyme is inactive under normal plant growth conditions, this potentially allows its expression in plants without negative effects on growth and development, and subsequent heat-inducible activation. Furthermore we demonstrate that the recombinant enzyme acts in high concentrations of ionic liquids and can therefore degrade α-cellulose or even complex cell wall preparations under those pretreatment conditions. Conclusion The hyperthermophilic endoglucanase SSO1354 with its unique features is an excellent tool for advanced biomass conversion. Here we demonstrate its expression in planta and the possibility for post harvest activation. Moreover the enzyme is suitable for combined pretreatment and hydrolysis applications. PMID:22928996

  12. Harnessing energy from plant biomass.

    PubMed

    Chang, Michelle C Y

    2007-12-01

    Biofuels derived from renewable plant biomass offer a potential carbon-neutral replacement for current liquid transportation fuels. Progress toward this initiative requires development of new methods to engineer energy crops with the desired chemical composition and physical characteristics, depolymerize lignocellulose to fermentable units, and program microbial metabolism for efficient conversion of sugars to ethanol.

  13. Complete oxidative conversion of lignocellulose derived non-glucose sugars to sugar acids by Gluconobacter oxydans.

    PubMed

    Yao, Ruimiao; Hou, Weiliang; Bao, Jie

    2017-11-01

    Non-glucose sugars derived from lignocellulose cover approximately 40% of the total carbohydrates of lignocellulose biomass. The conversion of the non-glucose sugars to the target products is an important task of lignocellulose biorefining research. Here we report a fast and complete conversion of the total non-glucose sugars from corn stover into the corresponding sugar acids by whole cell catalysis and aerobic fermentation of Gluconobacter oxydans. The conversions include xylose to xylonate, arabinose to arabonate, mannose to mannonate, and galactose to galactonate, as well as with glucose into gluconate. These cellulosic non-glucose sugar acids showed the excellent cement retard setting property. The mixed cellulosic sugar acids could be used as cement retard additives without separation. The conversion of the non-glucose sugars not only makes full use of lignocellulose derived sugars, but also effectively reduces the wastewater treatment burden by removal of residual sugars. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Ethylenediamine pretreatment changes cellulose allomorph and lignin structure of lignocellulose at ambient pressure.

    PubMed

    Qin, Lei; Li, Wen-Chao; Zhu, Jia-Qing; Liang, Jing-Nan; Li, Bing-Zhi; Yuan, Ying-Jin

    2015-01-01

    Pretreatment of lignocellulosic biomass is essential to increase the cellulase accessibility for bioconversion of lignocelluloses by breaking down the biomass recalcitrance. In this work, a novel pretreatment method using ethylenediamine (EDA) was presented as a simple process to achieve high enzymatic digestibility of corn stover (CS) by heating the biomass-EDA mixture with high solid-to-liquid ratio at ambient pressure. The effect of EDA pretreatment on lignocellulose was further studied. High enzymatic digestibility of CS was achieved at broad pretreatment temperature range (40-180 °C) during EDA pretreatment. Herein, X-ray diffractogram analysis indicated that cellulose I changed to cellulose III and amorphous cellulose after EDA pretreatment, and cellulose III content increased along with the decrease of drying temperature and the increase of EDA loading. Lignin degradation was also affected by drying temperature and EDA loading. Images from scanning electron microscope and transmission electron microscope indicated that lignin coalesced and deposited on the biomass surface during EDA pretreatment, which led to the delamination of cell wall. HSQC NMR analysis showed that ester bonds of p-coumarate and ferulate units in lignin were partially ammonolyzed and ether bonds linking the phenolic monomers were broken during pretreatment. In addition, EDA-pretreated CS exhibited good fermentability for simultaneous saccharification and co-fermentation process. EDA pretreatment improves the enzymatic digestibility of lignocellulosic biomass significantly, and the improvement was caused by the transformation of cellulose allomorph, lignin degradation and relocalization in EDA pretreatment.

  15. Isolation of microorganisms for biological detoxification of lignocellulosic hydrolysates.

    PubMed

    López, M J; Nichols, N N; Dien, B S; Moreno, J; Bothast, R J

    2004-03-01

    Acid pretreatment of lignocellulosic biomass releases furan and phenolic compounds, which are toxic to microorganisms used for subsequent fermentation. In this study, we isolated new microorganisms for depletion of inhibitors in lignocellulosic acid hydrolysates. A sequential enrichment strategy was used to isolate microorganisms from soil. Selection was carried out in a defined mineral medium containing a mixture of ferulic acid (5 mM), 5-hydroxymethylfurfural (5-HMF, 15 mM), and furfural (20 mM) as the carbon and energy sources, followed by an additional transfer into a corn stover hydrolysate (CSH) prepared using dilute acid. Subsequently, based on stable growth on these substrates, six isolates--including five bacteria related to Methylobacterium extorquens, Pseudomonas sp, Flavobacterium indologenes, Acinetobacter sp., Arthrobacter aurescens, and one fungus, Coniochaeta ligniaria--were chosen. All six isolates depleted toxic compounds from defined medium, but only C. ligniaria C8 (NRRL 30616) was effective at eliminating furfural and 5-HMF from CSH. C. ligniaria NRRL 30616 may be useful in developing a bioprocess for inhibitor abatement in the conversion of lignocellulosic biomass to fuels and chemicals.

  16. Enzymatic Hydrolysis of Cellulosic Biomass

    SciTech Connect

    Yang, Bin; Dai, Ziyu; Ding, Shi-You; Wyman, Charles E.

    2011-08-22

    Biological conversion of cellulosic biomass to fuels and chemicals offers the high yields to products vital to economic success and the potential for very low costs. Enzymatic hydrolysis that converts lignocellulosic biomass to fermentable sugars may be the most complex step in this process due to substrate-related and enzyme-related effects and their interactions. Although enzymatic hydrolysis offers the potential for higher yields, higher selectivity, lower energy costs, and milder operating conditions than chemical processes, the mechanism of enzymatic hydrolysis and the relationship between the substrate structure and function of various glycosyl hydrolase components are not well understood. Consequently, limited success has been realized in maximizing sugar yields at very low cost. This review highlights literature on the impact of key substrate and enzyme features that influence performance to better understand fundamental strategies to advance enzymatic hydrolysis of cellulosic biomass for biological conversion to fuels and chemicals. Topics are summarized from a practical point of view including characteristics of cellulose (e.g., crystallinity, degree of polymerization, and accessible surface area) and soluble and insoluble biomass components (e.g., oligomeric xylan, lignin, etc.) released in pretreatment, and their effects on the effectiveness of enzymatic hydrolysis. We further discuss the diversity, stability, and activity of individual enzymes and their synergistic effects in deconstructing complex lignocellulosic biomass. Advanced technologies to discover and characterize novel enzymes and to improve enzyme characteristics by mutagenesis, post-translational modification, and over-expression of selected enzymes and modifications in lignocellulosic biomass are also discussed.

  17. Use of a microbe to mitigate inhibitors in biomass fermentations

    USDA-ARS?s Scientific Manuscript database

    The presence of inhibitory compounds in biomass sugars is a significant hurdle to conversion of biomass to fuels and chemicals. The fibrous nature of lignocellulosic biomass necessitates physical-chemical pretreatment to deconstruct plant cell walls and render cellulose accessible to enzymatic dige...

  18. Rheological modification of corn stover biomass at high solids concentrations

    Treesearch

    Joseph R. Samaniuk; C. Tim Scott; Thatcher W. Root; Daniel J. Klingenberg

    2012-01-01

    Additives were tested for their ability to modify the rheology of lignocellulosic biomass. Additive types included water-soluble polymers (WSPs), surfactants, and fine particles. WSPs were the most effective rheological modifiers, reducing yield stresses of concentrated biomass by 60–80% for additive concentrations of 1–2 wt. % (based on mass of dry biomass solids)....

  19. Lignocellulosic ethanol production by starch-base industrial yeast under PEG detoxification

    PubMed Central

    Liu, Xiumei; Xu, Wenjuan; Mao, Liaoyuan; Zhang, Chao; Yan, Peifang; Xu, Zhanwei; Zhang, Z. Conrad

    2016-01-01

    Cellulosic ethanol production from lignocellulosic biomass offers a sustainable solution for transition from fossil based fuels to renewable alternatives. However, a few long-standing technical challenges remain to be addressed in the development of an economically viable fermentation process from lignocellulose. Such challenges include the needs to improve yeast tolerance to toxic inhibitory compounds and to achieve high fermentation efficiency with minimum detoxification steps after a simple biomass pretreatment. Here we report an in-situ detoxification strategy by PEG exo-protection of an industrial dry yeast (starch-base). The exo-protected yeast cells displayed remarkably boosted vitality with high tolerance to toxic inhibitory compounds, and with largely improved ethanol productivity from crude hydrolysate derived from a pretreated lignocellulose. The PEG chemical exo-protection makes the industrial S. cerevisiae yeast directly applicable for the production of cellulosic ethanol with substantially improved productivity and yield, without of the need to use genetically modified microorganisms. PMID:26837707

  20. Lignocellulosic ethanol production by starch-base industrial yeast under PEG detoxification

    NASA Astrophysics Data System (ADS)

    Liu, Xiumei; Xu, Wenjuan; Mao, Liaoyuan; Zhang, Chao; Yan, Peifang; Xu, Zhanwei; Zhang, Z. Conrad

    2016-02-01

    Cellulosic ethanol production from lignocellulosic biomass offers a sustainable solution for transition from fossil based fuels to renewable alternatives. However, a few long-standing technical challenges remain to be addressed in the development of an economically viable fermentation process from lignocellulose. Such challenges include the needs to improve yeast tolerance to toxic inhibitory compounds and to achieve high fermentation efficiency with minimum detoxification steps after a simple biomass pretreatment. Here we report an in-situ detoxification strategy by PEG exo-protection of an industrial dry yeast (starch-base). The exo-protected yeast cells displayed remarkably boosted vitality with high tolerance to toxic inhibitory compounds, and with largely improved ethanol productivity from crude hydrolysate derived from a pretreated lignocellulose. The PEG chemical exo-protection makes the industrial S. cerevisiae yeast directly applicable for the production of cellulosic ethanol with substantially improved productivity and yield, without of the need to use genetically modified microorganisms.

  1. Effect of lignocellulosic composition and structure on the bioethanol production from different poplar lines.

    PubMed

    Duan, Xiaojian; Zhang, Changbo; Ju, Xuehai; Li, Qiongcui; Chen, Shouyi; Wang, Jingan; Liu, Zhongqi

    2013-07-01

    Branches from three transgenic poplar lines and their wild type line 107 were used to study the effect of lignocellulosic composition and structure on the production of glucose and ethanol. Experimental results showed that the transgenic line 18-1 had the high cellulose content and amorphous fibril structure. After poplar meals were pretreated with 10% NaOH and a mixture of hydrogen peroxide and acetic acid, their lateral order index decreased significantly. The highest glucose yield in enzymatic hydrolysis and ethanol yield from the substrate of 18-1 was much higher than that from feedstock of 107 by 192.7% and 108.7%, respectively. Scanning electron microscopy images confirmed that lignocellulose from the 18-1 could be destroyed by chemicals more easily than those from other lines. These results demonstrated that changing lignocellulose structure could be more effective on improving the digestibility and enzymatic hydrolysis of poplar biomass than increasing the cellulose content in biomass.

  2. Phenolic compounds: Strong inhibitors derived from lignocellulosic hydrolysate for 2,3-butanediol production by Enterobacter aerogenes.

    PubMed

    Lee, Sang Jun; Lee, Ju Hun; Yang, Xiaoguang; Kim, Sung Bong; Lee, Ja Hyun; Yoo, Hah Young; Park, Chulhwan; Kim, Seung Wook

    2015-12-01

    Lignocellulosic biomass are attractive feedstocks for 2,3-butanediol production due to their abundant supply and low price. During the hydrolysis of lignocellulosic biomass, various byproducts are formed and their effects on 2,3-butanediol production were not sufficiently studied compared to ethanol production. Therefore, the effects of compounds derived from lignocellulosic biomass (weak acids, furan derivatives and phenolics) on the cell growth, the 2,3-butanediol production and the enzymes activity involved in 2,3-butanediol production were evaluated using Enterobacter aerogenes ATCC 29007. The phenolic compounds showed the most toxic effects on cell growth, 2,3-butanediol production and enzyme activity, followed by furan derivatives and weak acids. The significant effects were not observed in the presence of acetic acid and formic acid. Also, feasibility of 2,3-butanediol production from lignocellulosic biomass was evaluated using Miscanthus as a feedstock. In the fermentation of Miscanthus hydrolysate, 11.00 g/L of 2,3-butanediol was obtained from 34.62 g/L of reducing sugar. However, 2,3-butanediol was not produced when the concentration of total phenolic compounds in the hydrolysate increased to more than 1.5 g/L. The present study provides useful information to develop strategies for biological production of 2,3-butanediol and to establish biorefinery for biochemicals from lignocellulosic biomass.

  3. Genome sequence of the lignocellulose-bioconverting and xylose-fermenting yeast Pichia stipitis

    Treesearch

    Thomas W. Jeffries; Igor V. Grigroriev; Jane Grimwood; Jose M. Laplaza; Andrea Aerts; Asaf Salamov; Jeremy Schmutz; Erika Lindquist; Paramvir Dehal; Harris Shapiro; Yong-Su Jin; Volkmar Passoth; Paul M. Richardson

    2007-01-01

    Xylose is a major constituent of plant lignocellulose, and its fermentation is important for the bioconversion of plant biomass to fuels and chemicals. Pichia stipitis is a well-studied, native xylose-fermenting yeast. The mechanism and regulation of xylose metabolism in P. stipitis have been characterized and genes from P. stipitis have been used to engineer xylose...

  4. In planta expression of hyperthermophilic enzymes as a strategy for accelerated lignocellulosic digestion.

    PubMed

    Mir, Bilal Ahmad; Myburg, Alexander A; Mizrachi, Eshchar; Cowan, Don A

    2017-09-13

    Conversion of lignocellulosic biomass to biofuels and biomaterials suffers from high production costs associated with biomass pretreatment and enzymatic hydrolysis. In-planta expression of lignocellulose-digesting enzymes is a promising approach to reduce these cost elements. However, this approach faces a number of challenges, including auto-hydrolysis of developing cell walls, plant growth and yield penalties, low expression levels and the limited stability of expressed enzymes at the high temperatures generally used for biomass processing to release fermentable sugars. To overcome these challenges we expressed codon-optimized recombinant hyperthermophilic endoglucanase (EG) and xylanase (Xyn) genes in A. thaliana. Transgenic Arabidopsis lines expressing EG and Xyn enzymes at high levels without any obvious plant growth or yield penalties were selected for further analysis. The highest enzyme activities were observed in the dry stems of transgenic lines, indicating that the enzymes were not degraded during stem senescence and storage. Biomass from transgenic lines exhibited improved saccharification efficiency relative to WT control plants. We conclude that the expression of hyperthermophilic enzymes in plants is a promising approach for combining pretreatment and enzymatic hydrolysis processes in lignocellulosic digestion. This study provides a valid foundation for further studies involving in planta co-expression of core and accessory lignocellulose-digesting enzymes.

  5. Techniques for the evolution of robust Pentose-fermenting yeast for bioconversion of Lignocellulose to Ethanol

    USDA-ARS?s Scientific Manuscript database

    Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol and other bio-products via the processing steps of pretreatment, enzyme hydrolysis and microbial conversion. Traditional industrial yeasts do not ferment xylose and are not able to grow, survi...

  6. Rheology measurements of a biomass slurry : an inter-laboratory study

    Treesearch

    Jonathan J. Stickel; Jeffrey S. Knutsen; Matthew W. Liberatore; Wing Luu; Douglas W. Bousfield; Daniel J. Klingenberg; Tim Scott; Thatcher W. Root; Max R. Ehrhardt; Thomas O. Monz

    2009-01-01

    The conversion of biomass, specifically lignocellulosic biomass, into fuels and chemicals has recently gained national attention as an alternative to the use of fossil fuels. Increasing the concentration of the biomass solids during biochemical conversion has a large potential to reduce production costs. These concentrated biomass slurries have highly viscous, non-...

  7. A review of enzymes and microbes for lignocellulosic biorefinery and the possibility of their application to consolidated bioprocessing technology.

    PubMed

    Hasunuma, Tomohisa; Okazaki, Fumiyoshi; Okai, Naoko; Hara, Kiyotaka Y; Ishii, Jun; Kondo, Akihiko

    2013-05-01

    The biorefinery manufacturing process for producing chemicals and liquid fuels from biomass is a promising approach for securing energy and resources. To establish cost-effective fermentation of lignocellulosic biomass, the consolidation of sacccharification and fermentation processes is a desirable strategy, but requires the development of microorganisms capable of cellulose/hemicellulose hydrolysis and target chemical production. Such an endeavor requires a large number of prerequisites to be realized, including engineering microbial strains with high cellulolytic activity, high product yield, productivities, and titers, ability to use many carbon sources, and resistance to toxic compounds released during the pretreatment of lignocellulosic biomass. Researchers have focused on either engineering naturally cellulolytic microorganisms to improve product-related properties or modifying non-cellulolytic organisms with high product yields to become cellulolytic. This article reviews recent advances in the development of microorganisms for the production of renewable chemicals and advanced biofuels, as well as ethanol, from lignocellulosic materials through consolidated bioprocessing.

  8. Biotechnological strategies to overcome inhibitors in lignocellulose hydrolysates for ethanol production: review.

    PubMed

    Parawira, W; Tekere, M

    2011-03-01

    One of the major challenges faced in commercial production of lignocellulosic bioethanol is the inhibitory compounds generated during the thermo-chemical pre-treatment step of biomass. These inhibitory compounds are toxic to fermenting micro-organisms. The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds formed or released during thermo-chemical pre-treatment step such as acid and steam explosion. This review describes the application and/or effect of biological detoxification (removal of inhibitors before fermentation) or use of bioreduction capability of fermenting yeasts on the fermentability of the hydrolysates. Inhibition of yeast fermentation by the inhibitor compounds in the lignocellulosic hydrolysates can be reduced by treatment with enzymes such as the lignolytic enzymes, for example, laccase and micro-organisms such as Trichoderma reesei, Coniochaeta ligniaria NRRL30616, Trametes versicolor, Pseudomonas putida Fu1, Candida guilliermondii, and Ureibacillus thermosphaericus. Microbial and enzymatic detoxifications of lignocellulosic hydrolysate are mild and more specific in their action. The efficiency of enzymatic process is quite comparable to other physical and chemical methods. Adaptation of the fermentation yeasts to the lignocellulosic hydrolysate prior to fermentation is suggested as an alternative approach to detoxification. Increases in fermentation rate and ethanol yield by adapted micro-organisms to acid pre-treated lignocellulosic hydrolysates have been reported in some studies. Another approach to alleviate the inhibition problem is to use genetic engineering to introduce increased tolerance by Saccharomyces cerevisiae, for example, by overexpressing genes encoding enzymes for resistance against specific inhibitors and altering co-factor balance. Cloning of the laccase gene followed by

  9. Enhancement of lignocellulose-carbon nanotubes composites by lignocellulose grafting.

    PubMed

    Huang, Jintian; Zhang, Shaobo; Zhang, Feiran; Guo, Zhiqing; Jin, Liping; Pan, Yefei; Wang, Yu; Guo, Tongcheng

    2017-03-15

    Lignocellulose (LNC) multi-walled carbon nanotubes (MWCNTs) composites were synthesized by covalently grafting a natural polymer, lignocellulose, onto MWCNTs in an ionic liquid, 1-allyl-3-methylimidazolium chloride (AmimCl). Furthermore, the grafting of LNC facilitated the dispersion of the MWCNTs in AmimCl and MWCNTs/LNC films. The elongation at break and tensile strength of grafted-MWCNTs/LNC films with 3wt% of MWCNTs content were 12.2% and 106.7MPa respectively, which was almost 93.7% and 10.7% higher than those of the pristine MWCNTs/LNC films. This finding clearly revealed that the mechanical properties of grafted-MWCNTs/LNC films were dramatically superior to those of the MWCNTs/LNC films.

  10. Lignocellulose Degradation Mechanisms Across the Tree of Life

    DOE PAGES

    Cragg, Simon M.; Beckham, Gregg T.; Bruce, Neil C.; ...

    2015-11-14

    Organisms use diverse mechanisms involving multiple complementary enzymes, particularly glycoside hydrolases (GHs), to deconstruct lignocellulose. Lytic polysaccharide monooxygenases (LPMOs) produced by bacteria and fungi facilitate deconstruction as does the Fenton chemistry of brown-rot fungi. Lignin depolymerisation is achieved by white-rot fungi and certain bacteria, using peroxidases and laccases. Meta-omics is now revealing the complexity of prokaryotic degradative activity in lignocellulose-rich environments. Protists from termite guts and some oomycetes produce multiple lignocellulolytic enzymes. We found that the Lignocellulose-consuming animals secrete some GHs, but most harbour a diverse enzyme-secreting gut microflora in a mutualism that is particularly complex in termites. Shipworms however,more » house GH-secreting and LPMO-secreting bacteria separate from the site of digestion and the isopod Limnoria relies on endogenous enzymes alone. Moreover, the omics revolution is identifying many novel enzymes and paradigms for biomass deconstruction, but more emphasis on function is required, particularly for enzyme cocktails, in which LPMOs may play an important role.« less

  11. Lignocellulose degradation mechanisms across the Tree of Life.

    PubMed

    Cragg, Simon M; Beckham, Gregg T; Bruce, Neil C; Bugg, Timothy D H; Distel, Daniel L; Dupree, Paul; Etxabe, Amaia Green; Goodell, Barry S; Jellison, Jody; McGeehan, John E; McQueen-Mason, Simon J; Schnorr, Kirk; Walton, Paul H; Watts, Joy E M; Zimmer, Martin

    2015-12-01

    Organisms use diverse mechanisms involving multiple complementary enzymes, particularly glycoside hydrolases (GHs), to deconstruct lignocellulose. Lytic polysaccharide monooxygenases (LPMOs) produced by bacteria and fungi facilitate deconstruction as does the Fenton chemistry of brown-rot fungi. Lignin depolymerisation is achieved by white-rot fungi and certain bacteria, using peroxidases and laccases. Meta-omics is now revealing the complexity of prokaryotic degradative activity in lignocellulose-rich environments. Protists from termite guts and some oomycetes produce multiple lignocellulolytic enzymes. Lignocellulose-consuming animals secrete some GHs, but most harbour a diverse enzyme-secreting gut microflora in a mutualism that is particularly complex in termites. Shipworms however, house GH-secreting and LPMO-secreting bacteria separate from the site of digestion and the isopod Limnoria relies on endogenous enzymes alone. The omics revolution is identifying many novel enzymes and paradigms for biomass deconstruction, but more emphasis on function is required, particularly for enzyme cocktails, in which LPMOs may play an important role. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Sustainable Biomass Supply Systems

    SciTech Connect

    Erin Searcy; Dave Muth; Erin Wilkerson; Shahab Sokansanj; Bryan Jenkins; Peter Titman; Nathan Parker; Quinn Hart; Richard Nelson

    2009-04-01

    The U.S. Department of Energy (DOE) aims to displace 30% of the 2004 gasoline use (60 billion gal/yr) with biofuels by 2030 as outlined in the Energy Independence and Security Act of 2007, which will require 700 million tons of biomass to be sustainably delivered to biorefineries annually. Lignocellulosic biomass will make an important contribution towards meeting DOE’s ethanol production goals. For the biofuels industry to be an economically viable enterprise, the feedstock supply system (i.e., moving the biomass from the field to the refinery) cannot contribute more that 30% of the total cost of the biofuel production. The Idaho National Laboratory in collaboration with Oak Ridge National Laboratory, University of California, Davis and Kansas State University are developing a set of tools for identifying economical, sustainable feedstocks on a regional basis based on biorefinery siting.