Production of Bioethanol from Palm Oil Mill Effluent using Starter Cultures

Abstract

Palm Oil Mill Effluent (POME) has great potential as a substrate for acetone, butanol and ethanol fermentation because it contains a mixture of carbohydrates including starch, hemicellulose, sucrose and other carbohydrates that can be utilized by microorganisms. Hence microorganisms were isolated from spontaneously fermenting POME, the predominant strains were selected as starters and the effect of starters singly and in combination for bioethanol production was evaluated/determined. POME was spontaneously fermented for 21 days from which samples were taken every 3 days for analyses of pH, microbial quality, ethanol content, free fatty acid and lipase activity. Microorganisms isolated were characterized and identified. Moulds isolated were strains of Aspergillus and Penicillum genera, yeast were Yarrowia lipolytica, Saccharomyces cerevisiae and Candida spp., while bacteria were strains of Bacillus spp. and Micrococus sp. Sterile palm oil mill effluent was fermented with the starter cultures for 12 days and analyzed every 3 days for bioethanol production. Saccharomyces cerevisiae, while used singly, produced the highest bioethanol (3.70%) concentration. Statistical analysis shows that bioethanol and percentage free fatty acid production by single and combined starter fermented POME is significantly different (P ≤0.05) while lipase production was not significantly different (P≥0.05). The study reveals that fermentation of POME for 12days at room temperature (30+20C) using Saccharomyces cerevisiae singly gives the highest bioethanol concentration. Therefore, the use of starter cultures for fermentation of POME for the production of bioethanol is a potential solution for the control of pollution generated from the annual disposal of POME.