scispace - formally typeset

Topic

Cellulase

About: Cellulase is a(n) research topic. Over the lifetime, 16172 publication(s) have been published within this topic receiving 479592 citation(s). The topic is also known as: cellulase.
Papers
More filters

Journal ArticleDOI
Ye Sun1, Jiayang Cheng1Institutions (1)
TL;DR: Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis, thereby increasing the cost of ethanol production from lignocellulosic materials.
Abstract: Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy source for the limited crude oil. There are mainly two processes involved in the conversion: hydrolysis of cellulose in the lignocellulosic biomass to produce reducing sugars, and fermentation of the sugars to ethanol. The cost of ethanol production from lignocellulosic materials is relatively high based on current technologies, and the main challenges are the low yield and high cost of the hydrolysis process. Considerable research efforts have been made to improve the hydrolysis of lignocellulosic materials. Pretreatment of lignocellulosic materials to remove lignin and hemicellulose can significantly enhance the hydrolysis of cellulose. Optimization of the cellulase enzymes and the enzyme loading can also improve the hydrolysis. Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis.

5,503 citations


Journal ArticleDOI
Abstract: Chairman: 1981—83 H. Deliweg (FRG); 1983—85 C. L. Cooney (USA); Vice-Chairman: 1981—83 C. L. Cooney (USA); 1983—85 M. Ringpfeil (GDR); Secretary: 1981—83 R. C. Righelato (UK); 1983—85 G. G. Stewart (Canada); Titular and Associate Members: H. T. Blachère (France; Titular 1981—83); V. K. Eroshin (USSR; Associate 1981—83); A. Fiechter (Switzerland; Associate 1981—83); T. K. Ghose (India; Titular 1981—85); P. P. Gray (Australia; Associate 1983—85); J. Holló (Hungary; Titular 1981—83); A. E. Humphrey (USA; Associate 1981—83); M. Linko (Finland; Associate 1983—85); R. C. Righelato (UK; Associate 1983—85); G. G. Stewart (Canada; Associate 1981—83); J. Takahashi (Japan; Titular 1981—83); J. E. Zajic (USA; Associate 1981—83); National Representatives: R. J. Ertola (Argentina; 1981—85); P. P. Gray (Australia; 1981—83); H. J. G. Wutzel (Austria; 1981—85); W. Borzani (Brazil; 1981—85); M. Moo-Young (Canada; 1983—85); B. Sikyta (Czechoslovakia; 1981—85); K. Von Meyenburg (Denmark; 1981—85); H. Dellweg (FRG; 1983—85); M. Linko (Finland; 1981—83); L. Penasse (France; 1983—85); M. Ringpfeil (GDR; 1981—83); J. Holló (Hungary; 1983—85); V. Jagannathan (India; 1983—85); L. Goldstein (Israel; 1983—85); F. Parisi (Italy; 1983—85); S. Fukui (Japan; 1981—85); B. G. Yeoch (Malaysia; 1983—85); 0. Ilnicka-Olejiniczak (Poland; 1981—83); E. Galas (Poland; 1983—85); A. Fiechter (Switzerland; 1983—85); V. Johanides (Yugoslavia; 1981—85).

5,307 citations


Journal ArticleDOI
TL;DR: A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.
Abstract: Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

4,494 citations


Journal ArticleDOI
Sunkyu Park1, Sunkyu Park2, John O. Baker2, Michael E. Himmel2  +2 moreInstitutions (2)
TL;DR: Four different techniques incorporating X-ray diffraction and solid-state 13C nuclear magnetic resonance (NMR) were compared using eight different cellulose preparations and it was found that the simplest method, which is also the most widely used, and which involves measurement of just two heights in the X- Ray diffractogram, produced significantly higher crystallinity values than did the other methods.
Abstract: Although measurements of crystallinity index (CI) have a long history, it has been found that CI varies significantly depending on the choice of measurement method. In this study, four different techniques incorporating X-ray diffraction and solid-state 13C nuclear magnetic resonance (NMR) were compared using eight different cellulose preparations. We found that the simplest method, which is also the most widely used, and which involves measurement of just two heights in the X-ray diffractogram, produced significantly higher crystallinity values than did the other methods. Data in the literature for the cellulose preparation used (Avicel PH-101) support this observation. We believe that the alternative X-ray diffraction (XRD) and NMR methods presented here, which consider the contributions from amorphous and crystalline cellulose to the entire XRD and NMR spectra, provide a more accurate measure of the crystallinity of cellulose. Although celluloses having a high amorphous content are usually more easily digested by enzymes, it is unclear, based on studies published in the literature, whether CI actually provides a clear indication of the digestibility of a cellulose sample. Cellulose accessibility should be affected by crystallinity, but is also likely to be affected by several other parameters, such as lignin/hemicellulose contents and distribution, porosity, and particle size. Given the methodological dependency of cellulose CI values and the complex nature of cellulase interactions with amorphous and crystalline celluloses, we caution against trying to correlate relatively small changes in CI with changes in cellulose digestibility. In addition, the prediction of cellulase performance based on low levels of cellulose conversion may not include sufficient digestion of the crystalline component to be meaningful.

2,087 citations


Journal ArticleDOI
Yi-Heng Percival Zhang1, Lee R. Lynd1Institutions (1)
TL;DR: It is suggested that it is timely to revisit and reinvigorate functional modeling of cellulose hydrolysis and that this would be highly beneficial if not necessary in order to bring to bear the large volume of information available on cellulase components on the primary applications that motivate interest in the subject.
Abstract: Information pertaining to enzymatic hydrolysis of cellulose by noncomplexed cellulase enzyme systems is reviewed with a particular emphasis on development of aggregated understanding incorporating substrate features in addition to concentration and multiple cellulase components. Topics considered include properties of cellulose, adsorption, cellulose hydrolysis, and quantitative models. A classification scheme is proposed for quantitative models for enzymatic hydrolysis of cellulose based on the number of solubilizing activities and substrate state variables included. We suggest that it is timely to revisit and reinvigorate functional modeling of cellulose hydrolysis, and that this would be highly beneficial if not necessary in order to bring to bear the large volume of information available on cellulase components on the primary applications that motivate interest in the subject.

1,750 citations


Network Information
Related Topics (5)
Fermentation

68.8K papers, 1.2M citations

91% related
Cellulose

59K papers, 1.4M citations

88% related
Starch

50.2K papers, 1M citations

85% related
Saccharomyces cerevisiae

32.1K papers, 1.6M citations

83% related
Enzyme

32.8K papers, 1.1M citations

82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202224
2021568
2020649
2019681
2018716
2017793

Top Attributes

Show by:

Topic's top 5 most impactful authors

John N. Saddler

110 papers, 11.3K citations

Michael E. Himmel

67 papers, 4.7K citations

Arkady P. Sinitsyn

58 papers, 1.9K citations

David Wilson

43 papers, 4.2K citations

Christian P. Kubicek

38 papers, 2.8K citations