C. tyrobutyricum ATCC 25755 is an acidogen with butyric and acetic acids as the main fermentation products from glucose and xylose. In the previous study, we have knocked out the acetate kinase in C. tyrobutyricum  and overexpressed an adhE2 gene encoding a bifunctional aldehyde/alcohol dehydrogenase to realize ~10 g/L butanol production. In this study, we constructed three different plasmids expressing a CoA-transferase and transformed in the ack-disrupted strain. It has further improved the performance of butanol production comprehensively. Interestingly, ctfAB overexpression also induced acetone production to a level of 4-7.5 g/L without the existence of a decarboxylase. To conquer the instability problem from heterologous plasmids, integrational mutagenesis is used to insert a non-replicative plasmid within the region of ack gene. Meanwhile, the insertion will also introduce an expression of adhE2 gene on the chromosomal level. This can significantly reduce the segregational instability and growth burden from heterologous plasmids.

Metabolic engineering of <i>Clostridium tyrobutyricum</i> for improved n-butanol production from glucose

245th National Meeting (2013)

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Metabolic engineering of Clostridium tyrobutyricum for improved n-butanol production from glucose