Isobutanol Production from Cellulose

Higashide, W., Li, Y., Yang, Y, and Liao, J.C. (2011) Metabolic engineering of Clostridium cellulolyticum for production of isobutanol from cellulose. Appl EnvirorL Microbiol., 77, 2727—2733. 

The direct conversion of cellulose to biofuels would be more favorable under high temperatures to favor cellulose hydrolysis and reduce the chance of contamination. Lin et al. [96] were successful in the production of isobutanol using the cellulytic thermophile C. thermocellum. They also confirmed that an alternative pathway to kivd existed in this organism a ferrodoxin-dependent oxidoreductase that decarboxylased a-ketoisovalerate to produce isobutyl-CoA and then reduced to isobutanol. Their best result showed a titer of 5.4gU of isobutanol from cellulose at 50 °C within 75 h and at 41% of the theoretical yield [96]. 

In addition to cellulose, cellobionic acid is another carbon feedstock that is commonly found in lignocellulose hydrolysate. Desai et al. [97] demonstrated that cellobionic acid could be used as a sole carbon source for the growth and production of isobutanol in E. coli. They were able to produce 2.7 gl of isobutanol from 10.4 gl of commercial cellobionic acid [97]. 

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