Symbiotic Bacteroides and Clostridium-rich methanogenic consortium enhanced biogas production of high-solid anaerobic digestion systems

Abstract The high-solid anaerobic digestion (AD) for anaerobic co-digestion of palm oil mill effluent (POME) and oil palm empty fruit bunches (EFB) has low degradation efficiency. The enhancement of biogas production and EFB degradation efficiency by Bacteroides and Clostridium-rich methanogenic consortium was investigated. A Bacteroides and Clostridium-rich methanogenic consortium have xylanase, FPase, endo-glucanase, and exo-glucanase activity of 9.2, 1.3, 2.1, and 1.5 IU·mL−1, respectively with EFB degradation efficiency of 57.5%. Methane production (79 m3-CH4·tonne−1-EFB) by Bacteroides and Clostridium-rich methanogenic consortium augmentation was increased by 67.2%. The real application of bioaugmentation in the feedstock mixing tank before a feed to the AD reactor significantly increased methane yield (376.7 mL-CH4·g-1-VS−) by 85.5%. Bioaugmentation of Bacteroides and Clostridium-rich methanogenic consortium increased the number of hydrolytic bacteria and strengthened symbiotic relationships with indigenous microorganisms resulting in high biogas production, accelerated hydrolysis, and reduced solids accumulation of the high-solid AD process.