1-Butanol production from glycerol by engineered Klebsiella pneumoniae

To utilize the by-product of biodiesel production, Klebsiella pneumoniae, a well-known glycerolfermenting microorganism, was engineered to produce 1-butanol. The modified CoA-dependent and 2-keto acid pathways were established by expressing the genes ter-bdhB-bdhA and kivd, respectively. The 1-butanol titer and specific BuOH yield were 15.03 mg L-1 and 27.79 mg-BuOH per g cell in KpTBB (K. pneumoniae overexpressing the genes ter-bdhB-bdhA), and 28.7 mg L-1 and 51.58 mg-BuOH per g cell in Kp-kivd (K. pneumoniae overexpressing the gene kivd), respectively. Moreover, the native products in K. pneumoniae fermentation were down regulated using the antisense RNA strategy. The resulting yield of 1,3-propanediol and 2,3-butanediol was reduced by 81% and 15%, respectively. This work reports a new strain, K. pneumoniae, for 1-butanol production and the application of an antisense RNA strategy as an effective method for reducing the main by-products.