Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

Abstract

BACKGROUND Anaerobic digestion of food waste is influenced by the selection of an adequate microbial inoculum. In this study, wastewater sludge, a methane (CH4)‐producing landfill solid sample and the combination of both [1:1 volatile solid (VS)] were tested as inocula to treat food waste modelled to the Mexican diet. Hence, biochemical methane potential assays at inoculum to substrate (I:S) ratios of 1–3 and each inoculum metagenome were determined. RESULTS Methane production was optimal at I:S = 1 for sludge and the combined inoculum, whereas for landfill solid sample increasing the proportion of inoculum was beneficial up to I:S = 2. The landfill solid sample produced more CH4 than commonly used sludge (311.5 ± 11.1 and 282.5 ± 18.1 mL CH4 g−1 VS, respectively) but presented an adaptation phase (four days). Combining inocula (I:S = 1) produced a synergistic effect in CH4 yield (374.5 ± 10.5 mL CH4 g−1 VS), biogas quality (58.0 ± 0.3% CH4) and COD removal (90.0 ± 0.6%) without start‐up time. Moreover, an enriched microbial community high in Archaea and Bacteria was observed, probably because of the incorporation of predominant members of each inoculum (Bacteroidetes, Firmicutes and Euryarchaeota in sludge, and Proteobacteria and Actinobacteria in landfill solid sample). Archaea was represented mainly by the genus Methanosaeta (order Methanosarcinales), suggesting that methanogenesis occurred by the acetoclastic pathway. CONCLUSION Food waste from Mexican diet was a suitable feedstock for biogas generation. Optimal conditions were observed when combining both inocula. Further studies on population dynamics during digestion would help understand the synergistic effect for effective industrial application. © 2018 Society of Chemical Industry

Microbial methane cycling in a landfill on a decadal time scale

“…Abbreviated references have been provided and the raw input data used to generate this figure can be found in File S4 . Data obtained from (in chronological order): (7, 11, 14, 15, 17–19, 21, 22, 32, 34, 49, 88–93).…”

Influência de aditivos na geração de biogás proveniente da degradação de resíduos sólidos urbanos: revisão sistemática

“…10, n. 24, p. 171-182. Sillas-Moreno et al (2018) observaram que, ao utilizar lodo de esgoto como inóculo na digestão anaeróbica de resíduos orgânicos provenientes de um aterro sanitário, foi obtido aumento na produção de metano, porém foi verificado uma fase de latência de quatro dias. Essa combinação provocou um efeito sinérgico no rendimento de metano e na qualidade do biogás, fazendo com que fosse proposto que novos estudos sejam realizados para analisar a dinâmica da população microbiana ao decorrer do processo de digestão, ajudando a elucidar o efeito sinérgico entre os inóculos e viabilizar a aplicação em larga escala.…”

A Review of Landfill Microbiology and Ecology: A Call for Modernization With ‘Next Generation’ Technology

“…Research in the area of biogas recovery from MSW landfills has often focused on increasing the efficiency of landfilled waste decomposition while balancing the energy/expenses put into the effort, e.g., 'bioreactor' landfills discussed above (Ge et al, 2016;Zahedi, 2018;Silas-Moreno et al, 2019). For example, Ge et al (2016) showed that an addition of exogenous bacteria (i.e., foreign to the landfills), specifically aerobic bacteria, could enhance the hydrolysis and acidogenesis processes of MSW degradation.…”