Biogas production, DOM performance and microbial community changes in anaerobic co-digestion of chicken manure with Enteromorpha and green waste

With the invasion of green tides and the increase of worldwide urban green areas, millions of tons of Enteromorpha (EN) and green waste (GW) needed to be reutilized. In mono-digestion, the low hydrolysis rate of Enteromorpha and green waste limited the biomethane production. In this study, chicken manure (CM), as co substance, was added into EN and GW digestion systems to improve the biomethane production. The maximum biomethane production rate exhibited 49.9% improvement in co-digestion (CM:GW = 1:3). Besides, the heterogeneity of EN and GW induced PARAFAC components variation. The location of humic-like substance and tryptophan-like substance has significantly changed in excitation-emission matrix (EEM) spectra. Moreover, co-digestion significantly enhanced the cellulase activity in EN and GW co-digestion with 234% and 30% enhancement, respectively. Furthermore, the microbial community analysis indicated that co-digestion enriched the hydrogenotrophic methanogens (Methanobacterium). The potential metabolic pathway analysis showed an increasing trend in the methanogenesis encoding enzyme abundance.

Automated summary

This study found that adding chicken manure as a co-substance can improve the biomethane production of Enteromorpha and green waste. It also showed changes in the excitation-emission matrix spectra and enhanced cellulase activity. Microbial community analysis and potential metabolic pathway analysis indicated that co-digestion enriched hydrogenotrophic methanogens.