Identification and cultivation of hydrogenotrophic methanogens from palm oil mill effluent for high methane production

• Published in: International journal of energy research Vol. 44; no. 13; pp. 10058 - 10070
• Main Authors: Woraruthai, Thamonwan, Kunno, Jadsada, Pongsopon, Mattana, Yansakon, Kanokwan, Phoopraintra, Pattamaporn, Chantiwas, Rattikan, Leartsakulpanich, Ubolsree, Chaiyen, Pimchai, Wongnate, Thanyaporn
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 25-10-2020; Hindawi Limited
• Subjects: Alternative energy sources; Anaerobic digestion; Anaerobic processes; Anaerobic treatment; Bacteria; Biogas; Biorefineries; biorefinery; Consortia; Cultivation; Digestion; Effluent treatment; Effluents; Genes; hydrogenotroph; Identification; Incubation period; Lagoons; Methane; Methanoculleus; methanogen; Methanogenic bacteria; microbial community; Microorganisms; Oil; Oil and gas industry; Organic acids; Palm oil; palm oil mill effluent; Primers; Refuse as fuel; rRNA 16S; Substrates; Vegetable oils; Wastewater pollution; Wastewater treatment; Water pollution
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.5618

Summary
By means of biorefinery, biogas production through anaerobic digestion is one of the most common treatments of wastewater in the palm oil industry. After biogas production, the treated palm oil mill effluent (POME) is generally discharged into the environment. However, certain level of hazardous compounds still exists in the treated wastewater, which can lead to the pollution of water bodies. In this study, we have investigated the dynamics of volatile organic acids dwelling in consecutive POME treatment lagoons as well as identified, and categorized, microbial species responsible for the treatment process. Bacteria and methanogens, both hydrogenotrophic and acetoclastic, related to methane production were identified using mcrA and 16S rRNA genes specific primers. Two hydrogenotrophic methanogens, Methanoculleus marisnigri and Methanoculleus chikugoensis, were found abundant in accordance with high formate concentration throughout the process of anaerobic digestion. This study has also isolated eight consortia of microbes that yielded different methane productions by utilizing formate as the substrate in the synthetic medium. The consortia of a group, containing M. marisnigri, M. chikugoensis, uncultured bacteria, Aminobacterium sp., and Ruminobacillus xylanolyticum, produced the highest methane yield of 259 mL/g COD after 25 days of incubation in the laboratory. The findings from this study are contributing to optimize and increase biogas production in POME, which will allow higher efficiency in palm oil mill wastewater treatment.
The investigation of volatile organic acids dynamics throughout the treatment process of palm oil mill effluent (POME) had led to the isolation of potential formate utilizing microbial consortia. After 25 days of culturing in formate synthetic medium, the consortium containing hydrogenotrophic methanogens; Methanoculleus marisnigri and Methanoculleus chikugoensis, uncultured bacteria, Aminobacterium sp., and Ruminobacillus xylanolyticum could produce the highest methane yield of 259 mL/g COD. The findings, here, can contribute to higher efficiency in palm oil mill wastewater treatment.