The enrichment of anaerobic fungi and methanogens showed higher lignocellulose degrading and methane producing ability than that of bacteria and methanogens.

In this study, rumen content was used to obtain three enrichments of anaerobic fungi and methanogens (F + M enrichment), bacteria and methanogens (B + M enrichment), and whole rumen content (WRC enrichment), to evaluate their respective ability to degrade lignocellulose and produce methane. Among the treatments, F + M enrichment elicited the strongest lignocellulose degradation and methane production ability with both rice straw and wheat straw as substrates. Quantitative real-time PCR analysis and diversity analyses of methanogens in the three enrichment treatments demonstrated that F + M had larger number of 16S rRNA gene copies of methanogens and higher relative abundance of Methanobrevibacter, the predominant methanogen found in all enrichments. Caecomyces was the main anaerobic fungal genus for co-culturing to provide substrates for methanogens in this enrichment. Importantly, the F + M enrichment was stable and could be maintained with transfers supplied every 3 days, confirming its potential utility in anaerobic digestion for lignocellulose degradation and methane production.