| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 70012 | Journal of Molecular Catalysis B: Enzymatic | 2013 | 9 Pages |
Bacterial β-glucosidase (BGL), as a major component of the cellulase system, is a rate limiting factor during enzymatic hydrolysis of cellulose. In an effort to obtain thermostable BGLs desirable for application in the conversion of cellulose to glucose, we report a novel recombinant BGL from the thermophile Caldicellulosiruptor bescii (CbBgl1A). CbBgl1A could cleave a range of cellooligosaccharides and aryl-β-glycosides and showed a substrate preference for 4-nitrophenyl β-d-glucopyranoside (pNPGlc) with a kcat/Km value of 84.0 s−1 mM−1. The difference in catalysis efficiency for cellobiose with pNPGlc was mainly caused by the weak binding ability as analyzed by kinetic assay and molecular modeling. The enzyme could tolerate a high concentration of glucose with a Ki value of 113.8 mM. CbBgl1A synergistically works with several endo- or exoglucanases. The highest synergy value of 2.6 was obtained for the hydrolysis of regenerated amorphous cellulose using a combination of cellobiohydrolase CbCbh48A from C. bescii and CbBgl1A at a molar ratio of 1:5, where the complete conversion of oligosaccharides to glucose was obtained in 2 h.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Cloning and overexpression of a novel thermophilic β-glucosidase (CbBgl1A) from Caldicellulosiruptor bescii. ► High tolerance of CbBgl1A against both high concentrations of substrate and product. ► High synergism of CbBgl1A with exocellulases in the hydrolysis of cellulose.
