Phage activity in anaerobic bioreactors

Research Project, 2024 – 2027

Anaerobic, mixed-culture bioreactors are used for production of biogas or carboxylic acids from organic waste streams such as sewage sludge, food waste, and agricultural residues. Prokaryotes (i.e., bacteria and archaea) carry out the key functions in the bioreactors. They constantly interact with phages, which are viruses that infect prokaryotes. Phages are highly abundant in anaerobic bioreactors, but very little is known about them. The goal of this project is to determine which phages are present in anaerobic bioreactors; which prokaryotic hosts they infect; and how reactor design, operation, and environmental conditions affect phage presence and activity. We will combine an explorative sampling campaign of full-scale anaerobic digesters in two countries with hypothesis-driven laboratory experiments. We use metagenomic sequencing to identify active phages and host interactions. Regular sampling of full-scale bioreactors for two years will show temporal variation of phages and the prokaryotic communities. Observations from the sampling campaign will guide laboratory experiments testing environmental and operational triggers of prophage induction in anaerobic prokaryotes. The geographic distribution of phages of relevance in anaerobic bioreactors will be examined by an extensive bioinformatic analysis of sequencing data in public databases. The project results will pave the way for the use of phage therapy for bioreactor control.