From mesophilic to thermophilic digestion: the transitions of anaerobic bacterial, archaeal, and fungal community structures in sludge and manure samples

Abstract

The shift of microbial communities during a transition from mesophilic anaerobic digestion (MAD) to thermophilic anaerobic digestion (TAD) was characterized in two treatments. One treatment was inoculated with sludge and the other was inoculated with manure. In this study, methane was produced both in MAD and TAD, but TAD has slightly more methane produced than MAD. A broad phylogenetic spectrum of bacterial, archaeal, and fungal taxa at thermophilic conditions was detected. Coprothermobacter, Bacillus, Haloplasma, Clostridiisalibacter, Methanobacterium, Methanothermobacter, Saccharomycetales, Candida, Alternaria, Cladosporium, and Penicillium were found almost exclusively in TAD, suggesting their adaptation to thermophilic conditions and ecological roles in digesting the organic compounds. The characterization of the lesser-known fungal community revealed that fungi probably constituted an important portion of the overall community within TAD and contributed to this process by degrading complex organic compounds. The shift of the microbial communities between MAD and TAD implied that temperature drastically affected the microbial diversity in anaerobic digestion. In addition, the difference in microbial communities between sludge and manure indicated that different source of inoculum also affected the microbial diversity and community.

Effect of Seasonal Temperature on the Performance and on the Microbial Community of a Novel AWFR for Decentralized Domestic Wastewater Pretreatment

“…In addition, VadinBC27_wastewater-sludge_group was also observed throughout the operation period. It might be participating in the degradation of amino acids and some refractory organic matters [56][57][58]. The genus Smithella, which could degrade propionate to acetate [42,59], was dominant in start-up (3.13%) and winter (3.5%), and this was probably one of the reasons of acetate accumulation.…”

Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion

“…compared to the rate in mesophilic systems(37 °C) (Sun et al, 2015). The high rate of reaction enhances the system's load bearing capacity and the productivity of thethermophilic system compared to the mesophilic system.…”

Temperature regulates methane production through the function centralization of microbial community in anaerobic digestion

“…In AD systems, thermodynamic equilibrium of the biochemical reactions (Wilson et al, 2008) and microbial community structure, activities and diversity (Gannoun et al, 2016;Gunnigle et al, 2015;Sun et al, 2015) can be influenced by temperature. For example, methanogens show higher growth rates at thermophilic condition, which may induce efficient methane production (Sun et al, 2015;Weiland, 2010). An increase of hydrogenotrophic methanogens at 55°C compared to 35°C (Tian et al, 2015), may result in alternative methanogenic pathways in AD Pap et al, 2015).…”