Digestates from the co-digestion of cattle rumen and manure improve the methane potential of maize silage

The utilization of lignocellulosic biomasses for biogas production can slow down the biogas generation process. This study aimed to develop an effective inoculant composed of cattle manure rumen for the anaerobic digestion of maize silage. Four different proportions of cattle manure and rumen were tested as inoculants (IN) in this biomass. Biogas characterization, methane production efficiency, and the composition of the microbial community (both in the inoculants and reactors) were evaluated. The addition of IN1 (100 % cattle rumen) was unable to degrade the silage into methane (0.0 L kgVS−1). The final volume of biogas and methane produced by silage inoculated with IN3 (169.6 L kgVS−1) and IN4 (150.8 L kgVS−1) was higher. Analysis of the Archaeal communities in the silage and IN treatments revealed that the number of Amplicon Sequence Variants (ASVs) associated with Bathyarchaeia, Methanosarcinaceae, and Methanomassiliicoccaceae increased with an increase in the content of cattle manure in the inoculants. The findings support the promising potential of biogas and methane production from maize silage.