Biohydrogen production from rice mill wastes by Clostridium acetobutylicum NCIM 2877

The production of biohydrogen from rice mill wastes, including rice bran and rice mill effluent by Clostridium acetobutylicum NCIM 2877 was investigated in a batch culture system and optimized the temperature and pH conditions. At 35 C-circle with initial pH of 5.2 a yield of 55.7 +/- 0.8 ml with 88.6 +/- 0.3% substrate utilization and at pH 6 the production was 68.7 +/- 0.9 ml with 85 +/- 1.0 % substrate utilization. Addition of metal ions resulted in better yield and substrate utilization efficiency of the bacteria. FeSO4.7H(2)O at a concentration of 50 mg/l gave 79.7 +/- 1.5 ml with 96% of substrate utilization. Cobalt effected the production greatly by giving 96.3 +/- 0.9 ml with 95.3 +/- 0.7% of substrate utilization whereas Nickel didn't showed much effective results by giving only a maximum of 74.7 +/- 1.5 ml production at 25 mg/l concentration. Conclusively, it can be stated that rice mill wastes can be used as a substrate and use of metal ions will play a key role in the enhancement of biohydrogen production.