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Enhanced hydrolysis of lignocellulosic biomass: Bi‐functional enzyme complexes expressed in Pichia pastoris improve bioethanol production from Miscanthus sinensis
Author(s) -
Shin Sang Kyu,
Hyeon Jeong Eun,
Kim Young In,
Kang Dea Hee,
Kim Seung Wook,
Park Chulhwan,
Han Sung Ok
Publication year - 2015
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201500081
Subject(s) - lignocellulosic biomass , clostridium thermocellum , pichia pastoris , chemistry , fermentation , xylose , pentose , biochemistry , biomass (ecology) , hemicellulose , cellulase , hydrolysis , ethanol fuel , pichia stipitis , biofuel , food science , microbiology and biotechnology , biology , recombinant dna , agronomy , gene
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.