Using a combined oxygen‐supply and substrate‐feeding strategy to improve 2,3‐butanediol production by metabolically engineered Klebsiella oxytoca KMS005

BACKGROUND There is much demand for and extensive application for 2,3‐butanediol (2,3‐BD) in various fields, and micro‐aerobic and substrate‐feeding conditions greatly affect microbial growth and production. The theoretical maximum of 2,3‐BD fermentative yield has rarely been reported. Therefore, our study aimed to develop an efficient combined oxygen‐supply and substrate‐feeding strategy to improve 2,3‐BD production yield in metabolically engineered Klebsiella oxytoca KMS005. RESULTS The optimized oxygen consumption for 2,3‐BD production by strain KMS005 was demonstrated at 9.2 g for 1 L working volume corresponding to KLa of 25.2 h −1 . During fed‐batch, a glucose feeding rate of 2 g h −1 starting at the end of the growth phase for 48 h followed by a final batch phase of 40 h was found likely to be satisfactory for 2,3‐BD production by the strain KMS005. A final 2,3‐BD concentration was obtained at 74.7 g L −1 with few by‐products formation. A theoretical maximum of 2,3‐BD production yield of 0.5 g g −1 substrate used was also approached. CONCLUSION Our oxygen‐supply strategy with the specific feeding pattern developed in this study allowed the highest fermentative production yield of 2,3‐BD ever reported. The KMS005 strain may be used as a biocatalyst for cost‐effective 2,3‐BD production from renewable substrates. In addition, the outcome might bring a message for further developments of simple fed‐batch fermentation under micro‐aeration conditions into larger scales for 2,3‐BD production by K. oxytoca KMS005 or even other microorganisms. © 2017 Society of Chemical Industry