title: Direct cellobiose production from cellulose using sextuple beta-glucosidase gene deletion Neurospora crassa mutants.
abstract: Direct cellobiose production from cellulose by a genetically modified fungus-Neurospora crassa, was explored in this study. A library of N. crassa sextuple beta-glucosidase (bgl) gene deletion strains was constructed. Various concentrations of cellobiose were detected in the culture broth of the N. crassa sextuple beta-glucosidase (bgl) gene deletion strains when grown on Avicel without exogenous cellulase addition. The sextuple bgl deletion strains expressing one of the three basally transcribed bgl genes are the best cellobiose producers. For most sextuple strains, the multiple bgl gene deletion has no negative effect on the production of other cellulases. The induction of major endoglucanases and exoglucanases on Avicel in most of the sextuple bgl deletions strains was as fast as or faster than that of the wild type, except for strain F4. The best cellobiose producing strain, F5, produced 7.7 g/L of cellobiose from 20 g/L of Avicel in four days and utilized the Avicel as fast as did the wild type (even in the presence of high cellobiose concentration). The cellobiose yield from cellulose was about 48.3%.
authors: Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors: Weihua
authors: W
authors: Wu
authors: Amanda
authors: A
authors: Hildebrand
authors: Takao
authors: T
authors: Kasuga
authors: Xiaochao
authors: X
authors: Xiong
authors: Zhiliang
authors: Z
authors: Fan
mesh_terms: D002475:Cellobiose / Q000096:biosynthesis*; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D003433:Crosses, Genetic; D004790:Enzyme Induction; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005800:Genes, Fungal; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D013045:Species Specificity; D001617:beta-Glucosidase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D002475:Cellobiose; D002482:Cellulose; D001617:beta-Glucosidase; D002480:Cellulase