Optimizing Fermentation Conditions for bioH2 Production with Clostridium Butyricum CGS2 Using Statistical Experimental Design

摘要

As the global temperature keeps rising, the demand for reliable and effective energy alternatives is increasingly urgent. Among the developing alternative energy resources, hydrogen is recognized as a clean and recyclable energy carrier and is considered one of the major energy sources in the future. Hydrogen fermentation is a non-pollutant way of producing H2. Among fermentative H2 production processes, the H2 production rate by dark fermentation is higher than photo fermentation, thereby having higher viability for commercial applications. In this study, an indigenous isolate Clostridium butyricum CGS2 able to convert sugar (such as glucose, fructose, sucrose and xylose) into hydrogen was used the bacterial H2 producer. Using sucrose as the carbon source in a batch process, C. butyricum CGS2 gave a maximum H2 production rate (vH2) and H2 yield (YH2) of 262.2 ml/h/l and 2.26 mol H2/mol sucrose, respectively. Response surface methodology (RSM) was employed to identify the optimal conditions for hydrogen production of C. butyricum CGS2 using sucrose concentration, temperature and pH as the primary operation parameters. With a performance index of Yh2, the optimum condition predicted from RSM analysis was: pH, 5.2; temperature, 35.1 °C; sucrose concentration, 22.5 g COD/I. Under this condition, the hydrogen content in the biogas was 58.5%, LH2 was 0.54 l/h/l, total hydrogen production was 7.2 I, and YH2 was 2.91 mol H2/mol sucrose. On the other hand, when ; H2 was used as the performance index, the optimum condition was: pH, 5.36; temperature, 35.1 °C; sucrose concentration, 26.1 g COD/I. This condition gave a hydrogen content of 63.3%, a YH2 of 3.26 mol H2/mol sucrose, a total hydrogen production of 10.5 I, and a H2 of 0.50 l/h/l. The validity of RSM predictions was confirmed by additional experiments, suggesting that using RSM design could attain an optimal culture condition for C. butyricum CGS2 to enhance its hydrogen production performance.