Optimization of biohydrogen production from sugarcane bagasse by mixed cultures using a statistical method

The aim of this study is to determine the optimum condition for biohydrogen production from sugarcane bagasse (SCB) hydrolysate using a central composite design and response surface methodology (RSM). SCB was hydrolyzed with 0.5% (v/v) sulfuric acid at 121 °C, 0.15 MPa for 60 min in an autoclave at a solid to liquid ratio of 1:15 (g:mL). Heat-treated bacterium obtained from a hydrogen producing fermentor was used as the inoculum. The interaction of three factors, i.e., substrate concentration, substrate:buffer ratio and inoculum:substrate ratio on hydrogen production potential (P) were investigated. The results indicated that the substrate concentration, substrate:buffer ratio and inoculum:substrate ratio had a significant influence effect on P. An optimal condition was found at substrate concentration of 22.77 g-total sugar L−1, 4.31 substrate:buffer ratio, and 0.31 inoculum:substrate ratio resulted in a maximum P of 6980 mL H2 L−1. The confirmation experiment results indicated that optimum P was statistically significant, from the predicted value obtained by RSM which suggests that RSM could be efficiently used to optimize a biohydrogen production from SCB hydrolysate using mixed cultures. These results indicates that the SCB hemicellulose hydrolysate is suitable as a fermentation media for producing biohydrogen. This approach will add value to SCB by converting agricultural waste into a safe and clean form of energy.