Isolation of biohydrogen producing strain from palm oil sludge pond

Abstract

Hydrogen is an environment-friendly source of energy which has the potential to be the alternative fuel to replace the fossil fuels. It is a carbon free fuel which does not provide the greenhouse effect to the environment. Palm oil mill effluent (POME) is an abundant agro-industrial waste in Malaysia which composed of lignocellulosic material. This lignocellulosic biomass can be used as substrate for biogas generation. A biohydrogen producing strain was isolated from submerged palm oil sludge pond. The isolated bacteria was identified by various preliminary test such as Gram stain test, acetone test and gas producing test. The isolated strain was characterized as Gram-positive, rod-shaped and showed a positive result in both acetone test and gas producing test. Tryptone-yeast extract-acetate (TYA) medium was used during biohydrogen production process. The volume of hydrogen produced was measured by water displacement method. The fermentation process was done with the initial glucose concentration of 10 g/L and under anaerobic condition at 37oC. The study resulted in the optimum optical density (OD) of the cell at 1.046 and the residual glucose concentration at 0.2 g/L, where the final pH was at 4.5. The maximum biohydrogen production rate was reached at 46 mL/h when the fermentation period was at 21st hour and it dropped to 33.02 mL/h at 49th hour. Maximum biohydrogen yield was obtained at 292.49 mol-H2/mol-glucose with the highest biogas production and the highest estimation of biohydrogen production was 2,610 mL and 1,618.2 mL respectively. Therefore, this study showed that the locally isolated bacteria had the potential to undergo Acetone-Butanol-Ethanol (ABE) fermentation in order to produce a renewable biofuel.