Microbial community signature of high-solid content methanogenic ecosystems

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Background:

• Anaerobic digestion (AD) is a key process for organic waste treatment and biogas production.
• High solid content in AD can influence microbial community structure and function.
• Understanding microbial dynamics is crucial for optimizing AD efficiency.

Purpose of the Study:

• To investigate the shifts in bacterial and archaeal communities during anaerobic digestion at high solid contents.
• To identify microbial biomarkers associated with methanogenesis activity and inhibition.
• To correlate microbial community structure with process performance under varying total solids (TS).

Main Methods:

• Batch tests were conducted across a range of total solids (TS) from 10% to 35%.
• Bacterial and archaeal community structures were analyzed using molecular techniques.
• Methanogenic activity and volatile fatty acids (VFAs) accumulation were monitored.

Main Results:

• High methanogenic activity was observed between 10% and 25% TS, with no distinct bacterial community structure.
• Methanogenesis was inhibited at 30% and 35% TS, linked to VFA accumulation.
• A specific bacterial signature, including Clostridium sp., emerged at high TS.
• Archaeal communities shifted from Methanobacterium sp. to Methanosarcina sp. with increasing TS.
• Specific bacterial and archaeal species were identified as biomarkers for methanogenesis inhibition.

Conclusions:

• Total solids content significantly impacts bacterial and archaeal communities in anaerobic digestion.
• High TS concentrations can lead to methanogenesis inhibition, characterized by VFA accumulation and specific microbial shifts.
• Identified microbial biomarkers can aid in monitoring and optimizing high solid anaerobic digestion processes.