Effects of bacterial bio-augmentation on the methane potential from facultative digestion of palm oil mill effluent and empty fruit bunch

• Main Authors: Chin, Kit Ling, Mohd Yaakob, Nurliyana, H'ng, Paik San, Lee, Chuan Li, Go, Wen Ze, Khoo, Pui San, Raja Nazrin, Raja Ahmad, Siti Nurul Ashikin
• Format: Article
• Language: English
• Published: Springer 2019
• Online Access: http://psasir.upm.edu.my/id/eprint/79575/1/Effects%20of%20bacterial%20bio-augmentation%20on%20the%20methane%20potential%20.pdf; http://psasir.upm.edu.my/id/eprint/79575/; https://link.springer.com/article/10.1007/s12649-019-00680-3

The methane productivity and biodegradability of facultative single- and co-digestion samples with palm oil mill wastes was evaluated on the effect of bacterial bio-augmentation. The single- and co-digestion substrates were bio-augmented with Bacillus subtillis and a methanogenic mixed culture of anaerobic microorganisms at different loading percentage. The highest methane production was recorded at 0.95 LCH4 from co-digestion sample augmented with 10% (v/v) B. subtilis while the highest methane yield of 0.7 mLCH4/g volatile solid, attained by single-digestion of palm oil mill effluent with addition of mixed methanogens at 5% (v/v). Cumulative methane production for single-digestion increased from 0.17 LCH4 to 0.32 LCH4 in response to the bio-augmentation treatment with 5% mixed methanogens. Conversely, additional mixed methanogens to co-digestion substrate resulted 75% reduction in methane production compared to non-augmented co-digestion substrate. Addition of B. subtilis into co-digestion was more beneficial than mixed methanogens due to the cellulolytic degradation ability of B. subtilis to digest the lignocellulolytic substances in empty fruit bunch.