Enzymes, Energy, and the Environment: A Strategic Perspective on the U.S. Department of Energy's Research and Development Activities for Bioethanol

Sheehan, John; Himmel, Michael E.

doi:10.1021/bp990110d

Cited by 187 publications

(84 citation statements)

References 84 publications

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“…Only a fraction of randomly absorbed CBH is believed to be catalytically active (Beldman et al, 1987;Sheehan and Himmel, 1999). If absorption occurs at a location such that the catalytic module is sufficiently close to an accessible cellulose chain end, the enzyme will be catalytically active.…”

Section: Cellobiohydrolasesmentioning

confidence: 99%

A functionally based model for hydrolysis of cellulose by fungal cellulase

Zhang

Lynd

2006

Biotechnol. Bioeng.

204

158

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A new functionally based kinetic model for enzymatic hydrolysis of pure cellulose by the Trichoderma cellulase system is presented. The model represents the actions of cellobiohydrolases I, cellobiohydrolase II, and endoglucanase I; and incorporates two measurable and physically interpretable substrate parameters: the degree of polymerization (DP) and the fraction of b-glucosidic bonds accessible to cellulase, F a (Zhang and Lynd, 2004). Initial enzyme-limited reaction rates simulated by the model are consistent with several important behaviors reported in the literature, including the effects of substrate characteristics on exoglucanase and endoglucanase activities; the degree of endo/exoglucanase synergy; the endoglucanase partition coefficient on hydrolysis rates; and enzyme loading on relative reaction rates for different substrates. This is the first cellulase kinetic model involving a single set of kinetic parameters that is successfully applied to a variety of cellulosic substrates, and the first that describes more than one behavior associated with enzymatic hydrolysis. The model has potential utility for data accommodation and design of industrial processes, structuring, testing, and extending understanding of cellulase enzyme systems when experimental date are available, and providing guidance for functional design of cellulase systems at a molecular scale. Opportunities to further refine cellulase kinetic models are discussed, including parameters that would benefit from further study.

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Section: Cellobiohydrolasesmentioning

confidence: 99%

A functionally based model for hydrolysis of cellulose by fungal cellulase

Zhang

Lynd

2006

Biotechnol. Bioeng.

204

158

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“…Bioconversion of cellulosic materials into fermentable sugars is a biorefining area that has invested enormous research effort, as it is a prerequisite for the subsequent production of bioenergy (Kumar et al 2008). For processing cellulosic biomass using commercial cellulase, the cost of production or purchase of enzymes is seen as a major obstacle to cost competitiveness (Vonsivers and Zacchi 1995;Gregg and Saddler 1997;Sheehan and Himmel 1999;Lynd et al 2001;Fan and Lynd 2007a;2007b). Although recent advances have reduced the cost of production of cellulase, it is still a significant cost component of pulp production at about $0.50 per gallon according to Novozymes (Green Car Congress 2010).…”

Section: Resultsmentioning

confidence: 99%

Potential Application of Ganoderma lucidum in Solid State Fermentation of Primary Sludge and Wheat Straw

Jesus¹,

Sain²,

Jeng³

et al. 2015

BioResources

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aThis study was conducted to investigate the production of lignocellulolytic enzymes and sugars by the fungus Ganoderma lucidum during solid state fermentation (SSF) using primary sludge (PS) and wheat straw (WS) as substrates at different concentration ratios. For fungal growth on SSF, 20 g of each blended substrate was added to Erlenmeyer flasks, which were autoclaved and maintained at room temperature prior to inoculation, whereas for submerged fermentation (SF), flasks containing 25 mL of potato dextrose broth (PDB) were used as standard to check the differences between both methods of growth, and then all flasks were incubated at 25 °C in the dark, during 8 and 16 days. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis from the protein extract obtained from solid state fermentation strongly suggested that G. lucidum could produce lignocellulolytic enzymes to degrade primary sludge and wheat straw. Among the sugars, the production of xylose and mannose was disturbed by adding primary sludge. With the addition of primary sludge, high glucuronic acid content was observed. The results suggest that the combination of primary sludge and wheat straw, at concentration ratios of 1:1 to 1:3, respectively, can be used as a raw material in the production of lignocellulolytic enzymes and the bioconversion of other types of biomass by G. lucidum.

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“…The alcoholic fermentation processes using agroindustrial products present a great challenge given the inconveniences that could arise when using raw material for human consumption or edible vegetable crops for the production of ethanol, and, on the other hand, the change in the use of land destined for the cultivation of vegetables that will be used to produce ethanol and bioethanol, which would sometimes lead to deforestation, food shortages, increase of desert regions and greater inability of soils to retain water, thus disrupting the balance of the hydrological cycle [4].…”

Section: Use Of Agroindustrial Waste In Fermentation Processesmentioning

confidence: 99%

Potential Production of Ethanol by Saccharomyces cerevisiae Immobilized and Coimmobilized with Zymomonas mobilis: Alternative for the Reuse of a Waste Organic

Ruiz-Marín¹,

Lopez²,

Narváez-García³

et al. 2017

Yeast - Industrial Applications

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Fermentation technologies have been developed to improve the production of ethanol and an alternative is the immobilization technology, which ofers the possibility of eiciently incorporating symbiotic bacteria in the same matrix. This study analyzes the potential use of immobilized and coinmobilized systems on beads of calcium alginate for ethanol production used mango waste (Mangifera indica) by Zymomonas mobilis and Saccharomyces cerevisiae compared with free cells culture and evaluate the efect of glucose concentration on productivity in coimmobilized system using a Chemostat reactor Ommi Culture Plus. For free cell culture, the productivity was higher for Z. mobilis ). The conversion of glucose to ethanol for coimmobilized system was higher (6.91 mol ethanol) with 50 g L -1 of glucose compared to 200 g L -1 of glucose (5.82 mol ethanol); suggesting the immobilized and coimmobilized cultures compared with free cells ofer an opportunity for the reuse of organic residues and high alcohol production.

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Enzymes, Energy, and the Environment: A Strategic Perspective on the U.S. Department of Energy's Research and Development Activities for Bioethanol

Cited by 187 publications

References 84 publications

A functionally based model for hydrolysis of cellulose by fungal cellulase

A functionally based model for hydrolysis of cellulose by fungal cellulase

Potential Application of Ganoderma lucidum in Solid State Fermentation of Primary Sludge and Wheat Straw

Potential Production of Ethanol by Saccharomyces cerevisiae Immobilized and Coimmobilized with Zymomonas mobilis: Alternative for the Reuse of a Waste Organic

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