Spo0A Gene Deficiency in Clostridium pasteurianum Results in Increased Butanol Production

Clostridium pasteurianum can produce butanol from glycerol, a waste product of biodiesel production. Nicholas R. Sandoval and his colleagues from the University of Delaware in the United States aim to couple butanol fermentation with biodiesel production to improve the economic viability of biofuels. However, crude glycerol contains growth-inhibiting by-products which inhibit production.

A culture of wild-type C. pasteurianum (ATCC 6013) was chemically-mutated, and the resulting population underwent selection in increasing concentrations of crude glycerol. The best-performing mutant, M150B, showed a 91% increase in butanol production compared to wild-types.

Mutations were identified in the M150B genome including a deletion mutation in the gene of the master transcriptional regulator of sporulation, Spo0A. A spo0A-single gene knockout strain was then developed and showed similar tolerance to crude glycerol as the evolved mutant strain M150B.

Growth-associated butanol production shows C. pasteurianum to be an attractive option for further engineering as it could be a good candidate for butanol production.