Effects of pH and fermentation strategies on 2,3-butanediol production with an isolated Klebsiella sp. Zmd30 strain

Abstract

This study examined the effects of pH-controlled and fermentation strategies on 2,3-butanediol (2,3-BDO) production by an isolated Klebsiella sp. Zmd30 strain. The pH value of 6.0 was found to be optimal among the investigated range of 4.5-9.0. In batch fermentation, the concentration, productivity and yield of 2,3-BDO were 57.17 g/l, 1.59 g/l/h and 82%, respectively. The 2,3-BDO production by Klebsiella sp. Zmd30 was found to be growth-associated. Higher 2,3-BDO concentration (110 g/l) and yield (94%) was obtained by using fed-batch operation, but the productivity was lower (0.88 g/l/h) as compared to that when using batch operation. The highest 2,3-BDO productivity of 2.81 g/l/h was obtained with the continuous culture at a hydraulic retention time (HRT) of 12h. The results suggest that fed-batch operation might be most suitable for commercialized 2,3-BDO production, due to obtaining a high concentration and yield.