Using of response surface methodology for optimization of biohydrogen production by Clostridium sp. tr2 isolated in Vietnam

Abstract

Biohydrogen is a clean, renewable, sustainable energy resource due to the highest energy density among all fuels and its combustion has no contribution to the environmental pollution and climate change. Biohydrogen production depends on a number of nutritional and environmental variables. The present paper is to determine the optimum condition for enhanced hydrogen production by a fermentative hydrogen-producing bacterium (designated as Clostridium sp. Tr2) isolated from buffalo-dung in Vietnam. The response surface methodology (RSM) was employed to determine the mutual effects of glucose, yeast extract and iron concentration on its hydrogen production in a batch condition. RSM analysis showed that the highest hydrogen production potential (Ps) was obtained under the condition of 10.18 g L^-1 glucose, 2.5 g L^-1 yeast extract and 58 mg L^-1 FeSO₄.7H₂O. All three factors had significant influences on the Ps. Glucose and iron concentration, yeast extract and iron concentration were interdependent or there was a significant interaction on Ps. Glucose and yeast extract concentration was slightly interdependent, or their interactive effect on Ps was not significant. Under optimum conditions, the maximum H₂ volume of 1080 ml (L medium)^-1 were found after 22 h facultative anaerobic fermentation. The experiment results show that the RSM analysis with the central composite design was useful for optimizing the biohydrogen-producing process by newly isolated Clostridium sp. Tr2 in Vietnam.