Meta-Omics-Supervised Characterization of Respiration Activities Associated with Microbial Immigrants in Anaerobic...

Area of Science:

• Microbial Ecology
• Environmental Microbiology
• Biogeochemistry

Background:

• Immigration shapes microbial community structure in various ecosystems.
• The role of immigrant microbes in local biochemical processes is not well understood.

Purpose of the Study:

• To characterize the activities and ecological impact of immigrant microbes in anaerobic sludge digesters.
• To investigate the potential of immigrants to engage in anaerobic respiration.

Main Methods:

• Meta-omics (metagenomics, 16S rRNA sequencing, metatranscriptomics) were used to analyze microbial communities.
• Batch tests were conducted with added electron acceptors (nitrate, nitrite, sulfate, elemental sulfur).
• Full-scale digesters in wastewater treatment plants were also assessed.

Main Results:

• Immigrants constituted the majority of respiration-capable populations in digesters.
• Up to 91% of added electron acceptors were consumed in batch tests.
• Respiration-capable immigrants were stimulated by electron acceptors, with upregulated respiration gene expression and suppressed methanogenesis.

Conclusions:

• Immigrant microbes possess the capability for anaerobic respiration in digesters.
• While present, the ecological role of immigrant anaerobic respiration may be minor in full-scale digesters compared to methanogenesis.