Production of 2,3-Butanediol from Crude Glycerol by Engineered Klebsiella oxytoca

2,3-Butanediol (2,3-BDO), a promising chemical due to its industrial applications, can be sourced from the biodiesel-derived crude glycerol. However, the formation of 1,3-propanediol (1,3-PDO), a by-product that may cause purity issues, as well as the low concentration, efficiency, and yield of 2,3-BDO from crude glycerol limits its use.

The team of Sukhyeong Cho from the Korea Institute of Science and Technology studied the production of 2,3-BDO from crude glycerol using the engineered Klebsiella oxytoca M3. The modified Klebsiella oxytoca M3 had two genes deleted: pduC, which encodes glycerol dehydratase large subunit, and ldhA, which encodes lactate dehydrogenase. These were deleted to reduce the formation of 1,3-PDO and lactic acid.

When the modified K. oxytoca M3 was used in fermentation with pure glycerol, cell growth and glycerol consumption were significantly enhanced and 2,3-BDO production was significantly higher than the parent strain. Notably, when crude glycerol was supplied, the engineered strain showed high 2,3-BDO production, efficiency, and yield without the formation of 1,3-PDO.

2,3-BDO production from glycerol was dramatically enhanced by disruption of two genes in K. oxytoca. 2,3-BDO production without 1,3-PDO was also achieved by using the engineered strain and crude glycerol.