Two-year microbial adaptation during hydrogen-mediated biogas upgrading process in a serial reactor configuration

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Background:

• Biogas upgrading is crucial for producing high-quality methane.
• Stable operation of biogas reactors can lead to microbial community shifts.
• Acetate accumulation can indicate specific microbial activities like homoacetogenesis.

Purpose of the Study:

• To explore microbial dynamics in a biogas upgrading system over two years.
• To investigate the impact of stable operating conditions on microbial communities.
• To understand the reasons behind acetate accumulation and its effect on the microbiome.

Main Methods:

• 16S rRNA amplicon sequencing was used to analyze microbial community composition.
• Monitoring of biogas upgrading performance, including methane content.
• Analysis of microbial adaptation trends based on relative abundance.

Main Results:

• Biogas upgrading achieved 99% methane content after long-term operation.
• Significant acetate accumulation was observed, suggesting increased homoacetogenic activity.
• The dominant archaeal species shifted from Candidatus Methanoculleus thermohydrogenotrophicum to Methanothermobacter thermautotrophicus.

Conclusions:

• Long-term stable operation enhances biogas upgrading efficiency but can alter microbial communities.
• Homoacetogenic activity plays a significant role in acetate accumulation.
• Methanothermobacter thermautotrophicus is a key species in adapted biogas upgrading microbiomes.