초록
<P>A newly isolated bacterium, designated as Klebsiella oxytoca M1, produced 2,3-butanediol (2,3-BDO) or acetoin selectively as a major product depending on temperature in a defined medium. K. oxytoca M1 produced 2,3-BDO mainly (0.32~0.34 g/g glucose) at 30 C while acetoin was a major product (0.32~0.38 g/g glucose) at 37 C. To investigate factors affecting product profiles according to temperature, the expression level of acetoin reductase (AR) that catalyzes the conversion of acetoin to 2,3-BDO was analyzed using crude protein extracted from K. oxytoca M1 grown at 30 and 37 C. The AR expression at 37 C was 12.8-fold lower than that at 30 C at the stationary phase and reverse transcription PCR (RT-PCR) analysis of the budC (encoding AR) was also in agreement with the AR expression results. When AR was overexpressed using K. oxytoca M1 harboring pUC18CM-budC, 2,3-BDO became a major product at 37 C, indicating that the AR expression level was a key factor determining the major product of K. oxytoca M1 at 37 C. The results in this study demonstrate the feasibility of using K. oxytoca M1 for the production of not only 2,3-BDO but also acetoin as a major product.</P>