Klebsiella oxytoca cellobiose

Csllobiose and Cellulose Fermentation Although some wild-type strains of E. coli can utilize cellobiose as a sole carbon source, its metabolism has not been careMly examined (Moniruzzaman et al., 1997). To confer the ability to ferment cellobiose, the casAB operon from Klebsiella oxytoca was introduced into E. coli. Klebsiella oxytoca contains a PTS, which enables it to utilize cellobiose. The K. oxytoca casAB operon, which encodes an enzyme II cellobiose and a phospho-p-glucosidase, was expressed in E. coli KOI 1. Unfortunately, expression was very poor. However, spontaneous mutants with 15-fold higher specific activities for cellobiose utilization were isolated. The best mutant produced 45 g/L ethanol with 94% of the theoretical yield. Two of the mutants were tested for their ability to produce ethanol from mixed waste office paper. The engineered strain produced 32.7 g/L ethanol with 72% of the theoretical yield. 

Wood BE, Ingram LO (1992) Ethanol production from cellobiose, amorphous cellulose, and crystalline cellulose by recombinant Klebsiella oxytoca containing chromosomally integrated Zymomonas mobilis genes for ethanol production and plasmids expressing thermostable cellulase genes from Clostridium thermocellum. Appl Environ Microbiol 58 2103-2110... 

Golias H, Dumsday GJ, Stanley GA, Pamment NB (2002) Evaluation of a recombinant Klebsiella oxytoca strain for ethanol production from cellulose by simultaneous saccharification and fermentation comparison with native cellobiose-utilising yeast strains and performance in co-culture with thermotolerant yeast and. Zymomonas mobilisJ Biotechnol 96(2) 155-168... 

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