Effect of chemical pretreatments on de-oiled rice bran for fermentative biohydrogen production

Increased demand of fossil fuels has lead to its shortfall and also for an urge for the search of alternative source of energy, which is non-polluting. Biohydrogen is an ideal fuel of future as it can be produced from different types of wastes, solids or liquids,  rich in organic matter and it does not produce any types of green house gases when combusted. Present work was carried out to enhance the biohydrogen production from de-oiled rice bran by pretreatment methods. Presence of high amount of carbohydrate (39% cellulose and 31% hemicellulose) and less lignin (4%) makes it an attractive feedstock for conversion into a variety of value-added products. De-oiled rice bran was taken as substrate and Clostridium acetobutylicum NCIM 2877 was used as seed culture for the fermentative biohydrogen production. Substrate was pretreated with different concentrations of acids and alkali. 1.5% H2SO4 pretreated de-oiled rice bran hydrosylate gave maximum of 97.5 ± 2.5 ml volumetric biohydrogen with conversion efficiency of 87.27 ± 0.84 % whereas maximum production of 130 ± 1.5 ml with a conversion efficiency of 65.66 ± 0.08 % was achieved at 0.25% of HCL. Among alkali, 0.1% NaOH pretreated de-oiled rice bran hydrosylate gave 99.0 ± 3.0 ml production with conversion efficiency of 83.36 ± 0.91 % and  0.75 % Ca(OH )2 pretreated de-oiled rice bran hydrosylate gave maximum production of  73.78 ± 7.4 ml. Therefore, by pretreatment of various complex biomasses, production of biohydrogen can be enhanced.