Microbial analysis in biogas reactors suffering by foaming incidents.

Area of Science:

• Biotechnology
• Environmental Microbiology
• Anaerobic Digestion

Background:

• Foam formation in biogas plants can cause process failure.
• Understanding the microbial drivers of foaming is crucial for stable biogas production.

Purpose of the Study:

• To investigate the correlation between foaming incidents and microbial community structure in biogas reactors.
• To identify specific microorganisms associated with foam formation.

Main Methods:

• Microbial ecology analysis using 16S rRNA gene sequencing.
• Characterization of continuous fed digesters overloaded with proteins, lipids, and carbohydrates.
• Comparison of microbial diversity in liquid and foam layers.

Main Results:

• Increased relative abundance of genera known for biosurfactant production or surface tension reduction after foaming.
• Identification of a microorganism similar to known foaming bacteria (e.g., Nocardia, Desulfotomaculum) that increased in abundance during foam events.
• Distinct microbial communities observed between liquid and foam layers.

Conclusions:

• Specific microorganisms, including those producing biosurfactants and those similar to known foaming bacteria, are strongly associated with foam formation in biogas reactors.
• The findings suggest a direct link between microbial ecology and foaming, necessitating further investigation for mitigation strategies.