title: Heterogeneous Expression and Functional Characterization of Cellulose-Degrading Enzymes from Aspergillus niger for Enzymatic Hydrolysis of Alkali Pretreated Bamboo Biomass.
abstract: Enzymatic hydrolysis of cellulosic biomass has caught much attention because of modest reaction conditions and environment friendly conditions. To reduce the cost and to achieve good quantity of cellulases, a heterologous expression system is highly favored. In this study, cellulose-degrading enzymes, GH3 family β-glucosidase (BGL), GH7 family-related cellobiohydrolases (CBHs), and endoglucanase (EG) from a newly isolated Aspergillus niger BE-2 are highly expressed in Pichia pastoris GS115. The strain produced EG, CBHs, and BGL enzymatic concentration of 0.56, 0.11, and 22 IU/mL, respectively. Mode of actions of the recombinant enzymes for substrate specificity and end product analysis are verified and found specific for cellulose degradation. Bamboo biomass saccharification with A. niger cellulase released a high level of fermentable sugars. Hydrolysis parameters are optimized to obtain reducing sugars level of 3.18 g/L. To obtain reducing sugars from a cellulosic biomass, A. niger could be a good candidate for enzymes resource of cellulase to produce reducing sugars from a cellulosic biomass. This study also facilitates the development of highly efficient enzyme cocktails for the bioconversion of lignocellulosic biomass into monosaccharides and oligosaccharides.
authors.affiliation: School of Life Science, Xiamen University, Xiamen, 361005, People's Republic of China, nasir.biotech@yahoo.com.
authors.forename: Nasir
authors.initials: N
authors.lastname: Ali
authors.forename: Zhang
authors.initials: Z
authors.lastname: Ting
authors.forename: Hailong
authors.initials: H
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Xue
authors.forename: Lihui
authors.initials: L
authors.lastname: Gan
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Minnan
authors.initials: M
authors.lastname: Long
mesh_terms: D000468:Alkalies / Q000737:chemistry; D001234:Aspergillus niger / Q000201:enzymology*; D018533:Biomass; D050260:Carbohydrate Metabolism; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000378:metabolism; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D000468:Alkalies; D002482:Cellulose; D001617:beta-Glucosidase; D002480:Cellulase; D043366:Cellulose 1,4-beta-Cellobiosidase