Dynamics of microbiome composition during anaerobic digestion of different renewable resources

Abstract BACKGROUND This study, using the whole metagenomic sequencing approach, provides an insight in the microbial dynamics that occurred during the anaerobic digestion of two crop substrates with different lignocellulose composition: cereal grains and grape pomace. RESULTS A total of 15 strains were identified as specifically characterising the two substrates. Among them some strains never detected in biogas reactors were identified: Clostridium isatidis, Methanothermobacter wolfeii and Methanobacter sp MB1 in cereal grains samples and Acetomicrobium hydrogeniformans, Acetomicrobium thermoterrenum in grape pomace samples. CONCLUSIONS The presence of bacteria as Acetomicrobium sp. and P.mucosa, involved in the degradation of lipids and protein-rich substrates, together with Methanosarcina sp. and P.bacterium 1109, able to tolerate high hydrogen pressures and high ammonia concentration derived by aminoacids degradation, suggest that a more complex syntrophic community is established in lignin-cellulose-enriched substrates; this evidence may help the development of new strategies to optimize the anaerobic digestion process of these kind of biomasses.