Metabolic Engineering of Thermoanaerobacterium thermosaccharolyticum for Increased n-Butanol Production

Abstract

Thermoanaerobacterium\rthermosaccharolyticum shows promise as a host for\rn-butanol production since it natively has the required genes involved in the\rn-butanol biosynthetic pathway. Overexpression of the natively occurring bcs operon containing the genes thl, hbd, crt, bcd, etfA, and etfB responsible for the formation of butyryl CoA increased the n-butanol\rproduction by 180% compared to the wild type from a n-butanol titer of 1.8 mM to\r5.1 mM. The deletion of one of the six alcohol dehydrogenase genes\rconfirmed that it was the primary gene responsible for ethanol and n-butanol\rproduction from acetyl CoA and butyryl CoA respectively.