Optimization for enhanced hydrogen production from Rhodobacter sphaeroides using response surface methodology

Abstract

In the present study, Rhodobacter sphaeroides isolated from sewage water was investigated for photoproduction of hydrogen under different cultural conditions. The variation was done in carbon and nitrogen sources along with growth factors. It was found that lactose promoted more amounts of hydrogen production under anaerobic light conditions followed by mannitol, galactose, and sucrose respectively. Uracil was observed as a better nitrogen source as compared to histidine and thiourea. After screening most appropriate carbon source, nitrogen source and growth factor by the classical approach, statistical optimization technique opted for the enhancement of hydrogen production. The response surface methodology adopted in the present work is an efficient tool for strategic experimental design for optimizing process parameters of a multivariable process. Firstly, experiments were performed according to Box-Behnken design. The model predicted is quadratic with a high value of R2 i.e. 0.9681 and maximum production recorded was 6.8 ml/30 ml. Thereafter, Central composite design based experiments were performed and 7.6 ml/30 ml production was achieved with an R2 value of 0.8848 fitted inthe quadratic model. The work presented here suggests a green approach of enhanced hydrogen production to meet the future demand of clean fuel.