Context. Wet anaerobic digestion is a promising technology for organic waste treatment and energy recovery. Diverse microorganisms are the basis of anaerobic biological treatment process, which sequentially shift under the selective pressure induced by operation parameter and environmental factors.
Gap. The underlying metabolic mechanisms in wet anaerobic digestion systems are still unclear due to the co-existing of diverse microorganisms and complex organic matters, which hinder the directional regulation of waste decomposition and resources recycling.
Aim. In this study, bench-top anaerobic digestion experiments of food waste (FW) were carried out for 3 months to explore the interactions between microorganisms and dissolved organic matter (DOM).
Methods. Temporal patterns of microbial and DOM succession were obtained by high-throughput sequencing and fourier transform ion cyclotron resonance mass spectrometry, respectively. Inter-domain ecological network method was adopted to visualize the changes in the interactions between microorganisms and DOM during the anaerobic digestion.
Findings. The results showed that microbial composition and diversity, as well as chemodiversity of DOM significantly changed over time. The environmental factors highly related to these changes included NH4+-N, s-carbohydrate, s-protein, alcohol and volatile fatty acids. Inter-domain network result showed that a few bacteria belong to Clostridiales, Synergistales, Sphaerobacterales, Lactobacillales and Caldilineales were identified as keynodes and associated to the majority of DOM molecular compositions, indicating rich material choices for microbial metabolism.
Utilization. These findings provide novel theoretical support for further research on the metabolic mechanism of wet anaerobic digestion of FW as well as directional regulation and control of engineering system.
