scholarly journals Defining the Frontiers of Synergism between Cellulolytic Enzymes for Improved Hydrolysis of Lignocellulosic Feedstocks

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1343
Author(s):  
Mpho S. Mafa ◽  
Brett I. Pletschke ◽  
Samkelo Malgas
Keyword(s):  
Value Added ◽  
Product Yield ◽  
Cellulose Hydrolysis ◽  
Cellulolytic Enzymes ◽  
Cellulolytic Enzyme ◽  
Key Factors ◽  
Cellulose Conversion ◽  
Lignocellulosic Feedstocks ◽  
Polysaccharide Monooxygenases ◽  
Hydrolysis Of

Lignocellulose has economic potential as a bio-resource for the production of value-added products (VAPs) and biofuels. The commercialization of biofuels and VAPs requires efficient enzyme cocktail activities that can lower their costs. However, the basis of the synergism between enzymes that compose cellulolytic enzyme cocktails for depolymerizing lignocellulose is not understood. This review aims to address the degree of synergism (DS) thresholds between the cellulolytic enzymes and how this can be used in the formulation of effective cellulolytic enzyme cocktails. DS is a powerful tool that distinguishes between enzymes’ synergism and anti-synergism during the hydrolysis of biomass. It has been established that cellulases, or cellulases and lytic polysaccharide monooxygenases (LPMOs), always synergize during cellulose hydrolysis. However, recent evidence suggests that this is not always the case, as synergism depends on the specific mechanism of action of each enzyme in the combination. Additionally, expansins, nonenzymatic proteins responsible for loosening cell wall fibers, seem to also synergize with cellulases during biomass depolymerization. This review highlighted the following four key factors linked to DS: (1) a DS threshold at which the enzymes synergize and produce a higher product yield than their theoretical sum, (2) a DS threshold at which the enzymes display synergism, but not a higher product yield, (3) a DS threshold at which enzymes do not synergize, and (4) a DS threshold that displays anti-synergy. This review deconvolutes the DS concept for cellulolytic enzymes, to postulate an experimental design approach for achieving higher synergism and cellulose conversion yields.

Blending of cellulolytic enzyme preparations from different fungal sources for improved cellulose hydrolysis by increasing synergism

RSC Advances ◽  
2014 ◽  
Vol 4 (84) ◽  
pp. 44726-44732 ◽  
Author(s):  
Mukund Adsul ◽  
Bhawna Sharma ◽  
Reeta Rani Singhania ◽  
Jitendra Kumar Saini ◽  
Ankita Sharma ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Cellulose Hydrolysis ◽  
Cellulolytic Enzyme ◽  
Enzyme Preparations ◽  
Fungal Enzyme ◽  
Enzyme Cocktail ◽  
Different Types ◽  
Hydrolysis Of

A prepared enzyme cocktail from different fungal enzyme preparations increases the hydrolysis of avicel/wheat straw by increasing synergism between the same or different types of cellulases.

scholarly journals Microbial Cellulose Utilization: Fundamentals and Biotechnology

2002 ◽  
Vol 66 (3) ◽  
pp. 506-577 ◽  
Author(s):  
Lee R. Lynd ◽  
Paul J. Weimer ◽  
Willem H. van Zyl ◽  
Isak S. Pretorius
Keyword(s):  
Consolidated Bioprocessing ◽  
Quantitative Description ◽  
Product Yield ◽  
Cellulose Hydrolysis ◽  
Taxonomic Diversity ◽  
Cellulosic Biomass ◽  
Limiting Factors ◽  
Cellulolytic Enzymes ◽  
Cellulase Enzymes ◽  
Microbial Cellulose

SUMMARY 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.

scholarly journals Eco-friendly consolidated process for co-production of xylooligosaccharides and fermentable sugars using self-providing xylonic acid as key pretreatment catalyst

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Zhou ◽  
Yong Xu
Keyword(s):  
Value Added ◽  
Glucose Production ◽  
Gluconobacter Oxydans ◽  
Fermentable Sugars ◽  
Acid Pretreatment ◽  
Cellulose Conversion ◽  
Xylonic Acid ◽  
Balance Analysis ◽  
High Yields ◽  
Hydrolysis Of

Abstract Background Obtaining high-value products from lignocellulosic biomass is central for the realization of industrial biorefinery. Acid pretreatment has been reported to yield xylooligosaccharides (XOS) and improve enzymatic hydrolysis. Moreover, xylose, an inevitable byproduct, can be upgraded to xylonic acid (XA). The aim of this study was to valorize sugarcane bagasse (SB) by starting with XA pretreatment for XOS and glucose production within a multi-product biorefinery framework. Results SB was primarily subjected to XA pretreatment to maximize the XOS yield by the response surface method (RSM). A maximum XOS yield of 44.5% was achieved by acid pretreatment using 0.64 M XA for 42 min at 154 °C. Furthermore, XA pretreatment can efficiently improve enzymatic digestibility, and achieved a 90.8% cellulose conversion. In addition, xylose, the inevitable byproduct of the acid-hydrolysis of xylan, can be completely converted to XA via bio-oxidation of Gluconobacter oxydans (G. oxydans). Subsequently, XA and XOS can be simultaneously separated by electrodialysis. Conclusions XA pretreatment was explored and exhibited a promising ability to depolymerize xylan into XOS. Mass balance analysis showed that the maximum XOS and fermentable sugars yields reached 10.5 g and 30.9 g per 100 g raw SB, respectively. In summary, by concurrently producing XOS and fermentable sugars with high yields, SB was thus valorized as a promising feedstock of lignocellulosic biorefinery for value-added products.

scholarly journals Valorization of waste forest biomass toward the production of cello-oligosaccharides with potential prebiotic activity by utilizing customized enzyme cocktails

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Anthi Karnaouri ◽  
Leonidas Matsakas ◽  
Eleni Krikigianni ◽  
Ulrika Rova ◽  
Paul Christakopoulos
Keyword(s):  
Enzymatic Hydrolysis ◽  
Scale Up ◽  
Forest Biomass ◽  
Value Added ◽  
Point Of View ◽  
Forest Residues ◽  
Cellulose Conversion ◽  
Enzyme Recycling ◽  
Glucose Ratio ◽  
Hydrolysis Of

Abstract Background Production of value-added materials from lignocellulosic biomass residues is an emerging sector that has attracted much attention as it offers numerous benefits from an environmental and economical point of view. Non-digestible oligosaccharides represent a group of carbohydrates that are resistant to gastrointestinal digestion, and therefore, they are considered as potential prebiotic candidates. Such oligosaccharides can derive from the biomass cellulose fraction through a controlled enzymatic hydrolysis that eliminates the yield of monomers. Results In the present study, hydrolysis of organosolv-pretreated forest residues (birch and spruce) was tested in the presence of four cellulases (EG5, CBH7, CBH6, EG7) and one accessory enzyme (LPMO). The optimal enzyme combinations were comprised of 20% EG5, 43% CBH7, 22% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of birch and 35% EG5, 45% CBH7, 10% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of spruce, leading to 22.3% and 19.1 wt% cellulose conversion into cellobiose, respectively. Enzymatic hydrolysis was applied on scale-up reactions, and the produced oligosaccharides (consisted of > 90% cellobiose) were recovered and separated from glucose through nanofiltration at optimized temperature (50 °C) and pressure (10 bar) conditions, yielding a final product with cellobiose-to-glucose ratio of 21.1 (birch) and 20.2 (spruce). Cellobiose-rich hydrolysates were tested as fermentative substrates for different lactic acid bacteria. It was shown that they can efficiently stimulate the growth of two Lactobacilli strains. Conclusions Controlled enzymatic hydrolysis with processive cellulases, combined with product recovery and purification, as well as enzyme recycling can potentially support the sustainable production of food-grade oligosaccharides from forest biomass.

Enzymatic Hydrolysis of Lignocellulosic Oil Palm Empty Fruit Bunch (EFB)

2015 ◽  
Vol 1113 ◽  
pp. 305-310
Author(s):  
Qadly Ameen Pahlawi ◽  
Nazlee Faisal Ghazali ◽  
Khairilanuar Mohd Hanim ◽  
Nik Azmi Nik Mahmood
Keyword(s):  
Enzymatic Hydrolysis ◽  
Enzymatic Reaction ◽  
Cellulose Hydrolysis ◽  
Enzyme Concentration ◽  
Empty Fruit Bunch ◽  
Enzyme Adsorption ◽  
Enzyme Loading ◽  
Cellulose Conversion ◽  
Hydrolysis Process ◽  
Hydrolysis Of

A preliminary study was performed on enzymatic hydrolysis process for treating empty fruit bunch (EFB) fibre. The bioconversion of cellulose hydrolysis was carried out with soluble cellulase from Trichodermareesei as the biocatalyst. Crucial trends such as substrate and enzyme loading influencing the enzymatic reaction were also studied in order to enhance the cellulose conversion. The results indicate that as the enzyme loading was increased, the EFB conversion also increased until it reached 115.63 FPU/g of enzyme concentration, beyond this values, the reverse occurred. On the other hand, as the substrate loading was increased the conversion decreased. Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing conversion at increasing enzyme loading and substrate loading.

Effect of Rhodococcus sp. pretreatment on cellulose hydrolysis of corn stalk

2020 ◽  
pp. 1-7
Author(s):  
Pan Hu ◽  
Huanan Li ◽  
Wenjing Xiao ◽  
Xiaohang Xie ◽  
Yuxian Yang ◽  
...  
Keyword(s):  
Cellulose Hydrolysis ◽  
Corn Stalk ◽  
Hydrolysis Of ◽  
Rhodococcus Sp

scholarly journals Generation of highly amenable cellulose-Iβ via selective delignification of rice straw using a reusable cyclic ether-assisted deep eutectic solvent system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chiranjeevi Thulluri ◽  
Ravi Balasubramaniam ◽  
Harshad Ravindra Velankar
Keyword(s):  
Enzymatic Hydrolysis ◽  
Rice Straw ◽  
Deep Eutectic Solvent ◽  
Solvent System ◽  
Cyclic Ether ◽  
Cellulolytic Enzymes ◽  
Ammonium Bromide ◽  
Selective Delignification ◽  
Cellulose Iβ ◽  
Hydrolysis Of

AbstractCellulolytic enzymes can readily access the cellulosic component of lignocellulosic biomass after the removal of lignin during biomass pretreatment. The enzymatic hydrolysis of cellulose is necessary for generating monomeric sugars, which are then fermented into ethanol. In our study, a combination of a deep eutectic (DE) mixture (of 2-aminoethanol and tetra-n-butyl ammonium bromide) and a cyclic ether (tetrahydrofuran) was used for selective delignification of rice straw (RS) under mild conditions (100 °C). Pretreatment with DE-THF solvent system caused ~ 46% delignification whereas cellulose (~ 91%) and hemicellulose (~ 67%) recoveries remained higher. The new solvent system could be reused upto 10 subsequent cycles with the same effectivity. Interestingly, the DE-THF pretreated cellulose showed remarkable enzymatic hydrolysability, despite an increase in its crystallinity to 72.3%. Contrary to conventional pretreatments, we report for the first time that the enzymatic hydrolysis of pretreated cellulose is enhanced by the removal of lignin during DE-THF pretreatment, notwithstanding an increase in its crystallinity. The current study paves way for the development of newer strategies for biomass depolymerization with DES based solvents.

Promotion effects of Pd on tungsten carbide catalysts: physiochemical properties and cellulose conversion performance

RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87756-87766 ◽  
Author(s):  
Glauco F. Leal ◽  
Silvia F. Moya ◽  
Debora M. Meira ◽  
Dean H. Barrett ◽  
Erico Teixeira-Neto ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Tungsten Carbide ◽  
Value Added ◽  
Aldol Reactions ◽  
One Pot ◽  
Cellulose Conversion ◽  
Physiochemical Properties ◽  
Conversion Performance

A multi-functional catalyst, which is able to perform both retro-aldol reactions followed by hydrogenation, is required to convert cellulose into value-added chemicals such as ethylene glycol (EG) in a one-pot reaction.

scholarly journals Oxidative Power: Tools for Assessing LPMO Activity on Cellulose

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1098
Author(s):  
Federica Calderaro ◽  
Loes E. Bevers ◽  
Marco A. van den Berg
Keyword(s):  
Experimental Design ◽  
Mode Of Action ◽  
Data Interpretation ◽  
Electron Donors ◽  
Cellulolytic Enzymes ◽  
Inhibiting Factors ◽  
Lytic Polysaccharide Monooxygenases ◽  
Polysaccharide Monooxygenases ◽  
Power Tools ◽  
Reliable Methods

Lytic polysaccharide monooxygenases (LPMOs) have sparked a lot of research regarding their fascinating mode-of-action. Particularly, their boosting effect on top of the well-known cellulolytic enzymes in lignocellulosic hydrolysis makes them industrially relevant targets. As more characteristics of LPMO and its key role have been elucidated, the need for fast and reliable methods to assess its activity have become clear. Several aspects such as its co-substrates, electron donors, inhibiting factors, and the inhomogeneity of lignocellulose had to be considered during experimental design and data interpretation, as they can impact and often hamper outcomes. This review provides an overview of the currently available methods to measure LPMO activity, including their potential and limitations, and it is illustrated with practical examples.

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