Bioaugmentation in anaerobic digesters: a systematic review

Area of Science:

• Microbiology
• Environmental Engineering
• Biotechnology

Background:

• Bioaugmentation, introducing specific microbes into anaerobic digestion (AD) systems, can improve methane production and resilience.
• AD systems often face suboptimal performance, necessitating strategies like bioaugmentation.
• A systematic literature review (SLR) is crucial for understanding current bioaugmentation research in AD.

Purpose of the Study:

• To systematically review and analyze research on bioaugmentation in anaerobic digestion (AD).
• To critically compare control methods used in AD bioaugmentation studies.
• To categorize bioaugmentation strains based on the four phases of anaerobic digestion.

Main Methods:

• Conducted a systematic literature review (SLR) following a predefined research protocol.
• Included search, appraisal, synthesis, and analysis of relevant studies.
• Grouped bioaugmentation microbes according to the hydrolysis, acidogenesis, acetogenesis, and methanogenesis phases of AD.

Main Results:

• Identified a diverse range of microbes used for bioaugmentation, with Clostridiaceae, Pseudomonadaceae, and Syntrophomonadaceae families being prominent.
• Most studies focused on the hydrolysis phase; acidogenesis studies were mainly linked to dark fermentation.
• Studies on acetogenesis, especially syntrophic propionate and butyrate oxidation (SPO and SBO), were significantly underrepresented.

Conclusions:

• Bioaugmentation is a promising strategy for enhancing AD performance.
• There is a critical need for more research into bioaugmentation strains for the acetogenesis phase, particularly SPO and SBO.
• Standardized control methods are essential for robust bioaugmentation studies in AD.