Journal ArticleDOI
Effects of Substrate Loading on Enzymatic Hydrolysis and Viscosity of Pretreated Barley Straw
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TLDR
The reactions subjected to gradual loading of substrate or substrate plus enzymes to increase the substrate levels from 5 to 15% w/w DM, consistently provided lower concentrations of glucose after 72 h of reaction; however, the initial rates of conversion varied in the different reactions.Abstract:
In this study, the applicability of a “fed-batch” strategy, that is, sequential loading of substrate or substrate plus enzymes during enzymatic hydrolysis was evaluated for hydrolysis of steam-pretreated barley straw. The specific aims were to achieve hydrolysis of high substrate levels, low viscosity during hydrolysis, and high glucose concentrations. An enzyme system comprising Celluclast and Novozyme 188, a commercial cellulase product derived from Trichoderma reesei and a β-glucosidase derived from Aspergillus niger, respectively, was used for the enzymatic hydrolysis. The highest final glucose concentration, 78 g/l, after 72 h of reaction, was obtained with an initial, full substrate loading of 15% dry matter weight/weight (w/w DM). Conversely, the glucose yields, in grams per gram of DM, were highest at lower substrate concentrations, with the highest glucose yield being 0.53 g/g DM for the reaction with a substrate loading of 5% w/w DM after 72 h. The reactions subjected to gradual loading of substrate or substrate plus enzymes to increase the substrate levels from 5 to 15% w/w DM, consistently provided lower concentrations of glucose after 72 h of reaction; however, the initial rates of conversion varied in the different reactions. Rapid cellulose degradation was accompanied by rapid decreases in viscosity before addition of extra substrate, but when extra substrate or substrate plus enzymes were added, the viscosities of the slurries increased and the hydrolytic efficiencies decreased temporarily.read more
Citations
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Journal ArticleDOI
A review of lignocellulose bioconversion using enzymatic hydrolysis and synergistic cooperation between enzymes--factors affecting enzymes, conversion and synergy.
J.S. Van Dyk,Brett I. Pletschke +1 more
TL;DR: This review examines the enzymes required to degrade various components of lignocellulose and the impact of pretreatments on the lignosic substrates and the enzyme required for degradation and the effect of and interaction between different hemicellulases on complex substrates.
Journal ArticleDOI
Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose
TL;DR: Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass.
Journal ArticleDOI
Enzymatic hydrolysis of biomass at high-solids loadings – A review
Alicia A. Modenbach,Sue E. Nokes +1 more
TL;DR: In this article, the authors provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis, including a brief discussion of the limitations, such as a lack of available water, difficulty with mixing and handling, insufficient mass and heat transfer, and increased concentration of inhibitors, associated with the use of high solids.
Journal ArticleDOI
Reactor design for minimizing product inhibition during enzymatic lignocellulose hydrolysis: I. Significance and mechanism of cellobiose and glucose inhibition on cellulolytic enzymes.
TL;DR: The data show that new strategies that place the bioreactor design at the center stage are required to alleviate the product inhibition and in turn to enhance the efficiency of enzymatic cellulose hydrolysis.
Journal ArticleDOI
Impact of microalgae characteristics on their conversion to biofuel. Part II: Focus on biomethane production.
TL;DR: This review summarizes information regarding anaerobic digestion of different microalgae species and covers the so‐claimed similarities of microalgal biomass and activated sludge as a substrate for anaer aerobic digestion.
References
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Journal ArticleDOI
Features of promising technologies for pretreatment of lignocellulosic biomass.
Nathan S. Mosier,Charles E. Wyman,Bruce E. Dale,Richard T. Elander,Y. Y. Lee,Mark T. Holtzapple,Michael R. Ladisch +6 more
TL;DR: This paper reviews process parameters and their fundamental modes of action for promising pretreatment methods and concludes that pretreatment processing conditions must be tailored to the specific chemical and structural composition of the various, and variable, sources of lignocellulosic biomass.
Journal ArticleDOI
Hydrolysis of lignocellulosic materials for ethanol production: a review.
Ye Sun,Jiayang Cheng +1 more
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.
Journal ArticleDOI
Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.
Teodoro Espinosa-Solares,John Bombardiere,Mark Chatfield,Max Domaschko,Michael Easter,David A. Stafford,Saul Castillo-Angeles,Nehemias Castellanos-Hernandez +7 more
TL;DR: Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance, and a modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost.
Journal ArticleDOI
Inhibition of cellulase, xylanase and β-glucosidase activities by softwood lignin preparations
Alex Berlin,Mikhail Yu. Balakshin,Neil R. Gilkes,John F. Kadla,Vera Maximenko,Satoshi Kubo,John N. Saddler +6 more
TL;DR: This study examines the inhibition of seven cellulase preparations, three xylanase preparations and a beta-glucosidase preparation by two purified, particulate lignin preparations derived from softwood using an organosolv pretreatment process followed by enzymatic hydrolysis.
Journal ArticleDOI
Adsorption of Trichoderma reesei CBH I and EG II and their catalytic domains on steam pretreated softwood and isolated lignin
TL;DR: The results indicate that the cellulose binding domain has a significant role in the unspecific binding of cellulases to lignin.