Improvement of 2,3-Butanediol Production In Enterobacter Aerogenes Via Lactate Dehydrogenase Deletion

Wednesday, October 19, 2011
Exhibit Hall B (Minneapolis Convention Center)
Min-Kyu Oh, Moo-Young Jung and Chiam-Yu Ng, Chemical and Biological Engineering, Korea university, Seoul, South Korea

2,3-Butanediol (2,3-BD) is a promising bulk chemical due to its extensive industrial applications. Through chemical reaction such as dehydration and esterification, 2,3-BD can be converted into various chemical compounds including 1,3-butadiene, diacetyl, methyl ethyl ketone (MEK; butan-2-one). These chemical compounds are used to make highly valued materials such as synthetic rubber, antifreeze agent, flavoring agent. Several microorganism species such as Klebsiella pneumonia, Klebsiella oxytoca and Enterobacter aerogenes are natural producers of 2,3-BD. Among these microorganisms, E. aerogenes is a facultative anaerobe, which is able to produce significant amounts of 2,3-BD in mixed fermentations, while generating a number of soluble and gaseous products. Furthermore, it has a high growth rate, high vitality in different types of environment, and is able to utilize diverse range of carbon sources. First, we performed medium optimization and pH control to obtain the optimal culture condition for high cell growth and high production of 2,3-BD product. In addition, we have successfully performed lactate dehydrogenase (ldh) gene knockout by using the Red lambda recombination method. ldh gene knock out strain showed improved yield of 2,3-BD when compare with wild type. We also overexpressed budA, budB, budC and bdh gene of E.aerogenes 2,3-BD pathway operon separately and the whole operon collectively to characterize the role of each gene and to enhance the production of 2,3-BD.

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