title: Cloning of thermostable cellulase genes of Clostridium thermocellum and their secretive expression in Bacillus subtilis.
abstract: Screening for the powerful cellulase genes with improved activities remains a challenge for the biorefinery research. In this study, five cellobiohydrolase genes and one endoglucanase gene sourced from Clostridium thermocellum DSM 1237, cbhA, celK, celO, cel48Y, cel48S, and celA were cloned into a newly established tool vector pP43JM2 and expressed in two Bacillus subtilis strains, B. subtilis WB600 and B. subtilis WB800, respectively. Most of the cellulases produced in the B. subtilis recombinants were efficiently secreted into the culture medium. These secreted soluble proteins showed distinct cellulase activities using phosphoric acid swollen cellulose (PASC) as the substrate and they also demonstrated strong synergistic effects for PASC, Avicel cellulose, and the dilute acid pretreated corn stover. The current work provided a quick secretive cloning method for screening cellulase genes and may provide a host strain for constructing a consolidated bioprocessing platform with the capacity of secretive expression of multiple cellulases.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Liu
authors.forename: Xiu-Juan
authors.initials: XJ
authors.lastname: Xin
authors.forename: Chun-Xiu
authors.initials: CX
authors.lastname: Li
authors.forename: Jian-He
authors.initials: JH
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Bao
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D044602:Cellulases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D003001:Cloning, Molecular; D048013:Acetivibrio thermocellus / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005822:Genetic Vectors; D006358:Hot Temperature; D006868:Hydrolysis; D007700:Kinetics; D010756:Phosphoric Acids; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010756:Phosphoric Acids; D011994:Recombinant Proteins; D002482:Cellulose; C030242:phosphoric acid; D044602:Cellulases