Producing 2,3-butanediol from agricultural waste using an indigenous Klebsiella sp. Zmd30 strain

Abstract

This study aimed to develop a low cost and high efficiency process for 2,3-butanediol (2,3-BDO) production by using Klebsiella sp. Zmd30 isolated from a hydrogen-producing anaerobic sludge. First, the effects of glucose concentration and nitrogen source on 2,3-BDO production with the Zmd30 strain were examined. The results show that the productivity and concentration of 2,3-BDO reached the highest values of 0.92g/l/h and 58g/l, respectively, when the glucose concentration was in the range of 160–180g/l. Urea was a better nitrogen source when considering both the 2,3-BDO production performance and the cost. Next, medium composition for the growth of the Zmd30 strain was optimized using the response surface methodology (RSM) to enhance 2,3-BDO production. Based on the RSM analysis, the optimal composition of glucose, urea and MnCl2·4H2O, H3BO3 and CoCl2·6H2O was 160, 2.28, 7.01×10−4, 1.49×10−4 and 5.70×10−3g/l, respectively. With this optimal medium, the 2,3-BDO productivity was improved to 1.15g/l/h. To reduce the production cost, bagasse and rice straw were used as feedstock for 2,3-BDO production. It was found that using hydrolyzed rice straw resulted in better productivity than using hydrolyzed bagasse, as the highest productivity (2.08g/l/h) and yield (62%) were obtained at an initial rice straw concentration of 150g/l.