Isolation and characterization of hydrogen producing bacteria from palm oil mill effluent (POME)

Abstract

Hydrogen gas and its usage in electricity generation and transportation is attracting wider interests nowadays. This is because it possesses a high-energy yields (122 kJ g–1), it is a renewable energy source, and does not contribute to the greenhouse effect. In Malaysia, 15.2 million tons of wastewater is generated annually by the palm oil industry. The wastewater is known as Palm Oil Mill Effluent (POME). This study is focused on the isolation and characterization of hydrogenproducing bacteria from POME. Samples were taken from the sludge and raw waste of palm oil processing effluent. Bacterial isolation was performed to isolate facultative anaerobes and strict anaerobes. The isolated colonies of bacteria were identified and characterized by microbiological analysis and biochemical tests (catalase, indole, nitrate reduction, urea, TSI and citrate test). From TSI test, it was found that one facultative anaerobe (out of 13 colonies altogether) produced gas; and all strict anaerobes produced gas (8 colonies altogether). The gas-producing colonies were then cultivated at 37°C for 24 hours in a synthetic media simulating starch wastewater for screening of hydrogen production. Hydrogen gas production was then analyzed using RGA (Residual Gas Analyzer). Results show that the facultative anaerobe colony did not produce hydrogen gas by starch fermentation; and four colonies obtained via strict anaerobe isolation show hydrogen production. These colonies can be the subject of future studies to optimize hydrogen production from waste materials.