Hydrogen production from agriculture waste by dark fermentation

Abstract

Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. Potential biomass that could be the substrates for biohydrogen generation include food waste, agricultural waste, dairy wastes, palm oil mill effluent (POME) and municipal solid waste. The objective of this research was to maximize the biohydrogen production in a waste medium (molasses). In this research, a biohydrogen producing bacteria, Clostridium butyricum was isolated from FERMPRO wastewater sludge (molasses) by using a heat-shock as a pre-treatment method for inoculum preparation. The cultivation and inoculum preparation was done using the Reinforced Clostridium Media (RCM). Pre-settled waste (molasses) with COD composition of 75 mg/L was used as a medium. Gas and hydrogen production was modelled using modified Gompertz equation. Study on the effect of inoculum activity showed that older inoculum will significantly increase the period of lag phase and also reduce the total of gas production. The absence of a lag phase made the gas production cease in 15 hours, which translate to a fast kinetic of gas production. Experiments were also conducted to study the effect of pH on gas production. The optimum condition of pH is pH 8.0 which the highest yield of hydrogen production obtained is 40 mL H2/L-medium at the constant temperature, 37 °C. Based on the result in this study, optimization of the culture condition for Clostridium butyricum provides highest potential for biohydrogen production.