Graphical abstract

Methanobacterium formicicum (Methanobacteriaceae family) is an endosymbiotic methanogenic Archaean found in the digestive tracts of ruminants and elsewhere. It has been significantly implicated in global CH 4 emission during enteric fermentation processes. In this review, we discuss current genomic and metabolic aspects of this microorganism for the purpose of the discovery of novel veterinary therapeutics. This microorganism encompasses a typical H 2 scavenging system, which facilitates a metabolic symbiosis across the H 2 producing cellulolytic bacteria and fumarate reducing bacteria. To date, five genome-scale metabolic models (iAF692, iMG746, iMB745, iVS941 and iMM518) have been developed. These metabolic reconstructions revealed the cellular and metabolic behaviors of methanogenic archaea. The characteristics of its symbiotic behavior and metabolic crosstalk with competitive rumen anaerobes support understanding of the physiological function and metabolic fate of shared metabolites in the rumen ecosystem. Thus, systems biological characterization of this microorganism may provide a new insight to realize its metabolic significance for the development of a healthy microbiota in ruminants. An in-depth knowledge of this microorganism may allow us to ensure a long term sustainability of ruminant-based agriculture.

No abstract

Biomethane is an environment-friendly, economic, and alternative energy resource for a clean and green future. In the present study, we have evaluated the biomethanation potential of acetate-utilizing methanogenic culture (AUMC) and gelatin-enriched mixed culture (GEMC) with Clostridium acetobutylicum NCIM 2841 (GEMC-CA.) on gelatin as a sole carbon and nitrogen source. Methods: We conducted experiments for examining the specific-methanogenic activity of these cultures in the metabolic assay media containing 1% gelatin. The produced methane and consumed gelatin were quantified by standard experimental methods. Exchange metabolites produced by these cultures were qualitatively analyzed by mass spectrometry. Results: Results of our study show that the growth-associated amino acid catabolism partially or completely supported the methanogenesis of these defined cultures. AUMC and GEMC found to be suitable for enhanced methanogenic activity on gelatin but a rapid degradation of amino acid was attributed by GEMC-CA. The ammonia released from these cultures was directly proportional to gelatin degradation. Mass spectral data analysis identified some key exchange metabolites from acidogenic culture and methanogenic culture for confirming the growth-associated methanogenesis. Conclusion: The biomethanation potential of these cultures on gelatin is coupled with the Stickland reactionsdirected methanogenesis in a syntrophic manner. The present study provides the importance for the development of a starter culture for the biomethanation of protein-based industrial wastes in effective ways.

No abstract