Biogas starter from genome-scale data for methanogenic bioprocessing of protein waste

• Published in: Systems Microbiology and Biomanufacturing 2024-04, Vol.4 (2), p.542-563
• Main Authors: Chellapandi, P., Saranya, S.
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Food Microbiology; Life Sciences; Metabolomics; Microbiology; Review
• ISSN: 2662-7655; 2662-7663
• DOI: 10.1007/s43393-023-00191-2

Biogas reactors operating with protein-based biomass have a high methane potential and industrial value. Protein-rich materials, including gelatin processing and ossein factory waste, are suitable feedstocks for use in ammonia-tolerant biogas digesters. However, the anaerobic digestion of these materials is limited by the accumulation of ammonia, hydrogen sulfide, and lactic acid. A stable biogas starter is required for efficient biogas production from protein-based mass and process performance. Hence, various ammonia-tolerant biogas inocula, immobilization carriers used, culture formulations, and stater stability are comprehensively summarized in this review. We also discuss engineered methanogens and mutants to improve methane productivity. The genera Methanoculleus and Methanosarcina are the dominant ammonia-tolerant methanogens studied in different biogas plants; however, their ammonia-tolerant molecular mechanisms remain unclear. Recent advances in omics technologies, systems, and synthetic biology of methanogens have been reviewed and discussed for the design and development of methanogenic inocula. We described the genome-centric characteristics of methanogenic consortia to improve the process efficiency under the desired environmental conditions. We also focus on the perspective of methanogenic culture development for the co-production of acetone–butanol–ethanol and methane as well as odor control strategies. A novel metabolic scaffold “Protein Catabolism-Directed Methanogenesis” was discovered from a methanogenic culture using a systems biology approach. This review offers new insights into the feasibility of ammonia-tolerant biogas starters and engineering synthetic pathways for recycling gelatin processing waste into biofuels in the energy sector.