Analysis of microbial community composition in a lab-scale membrane distillation bioreactor

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Membrane distillation bioreactors (MDBRs) are suitable for industrial wastewater treatment, especially with available waste heat.
• The role of microorganisms in MDBR performance remains largely undetermined.

Purpose of the Study:

• To investigate the microbial community structure and diversity within thermophilic MDBRs.
• To understand the relationship between microbial communities and operational parameters in MDBRs.

Main Methods:

• Bacterial, archaeal, and eukaryotic 16S/18S rRNA gene tag-encoded pyrosequencing of sludge DNA.
• Taxonomy-independent and taxonomy-dependent analyses of microbial communities.
• Correlation analysis between microbial community composition and operational parameters like conductivity, total nitrogen, and bound extracellular polymeric substances (EPS).

Main Results:

• Thermophilic MDBR microbial communities comprised low-diversity bacteria and high-diversity eukaryotes; no archaea were detected.
• Bacterial community composition correlated with conductivity, total nitrogen, and bound EPS.
• Eukaryotic community composition and the abundance of Candida correlated with bound EPS.

Conclusions:

• MDBR microbial communities are characterized by low bacterial and high eukaryotic diversity, with no archaea.
• These communities exhibit low resilience to operational changes, with nutrient composition strongly influencing dominant species.
• Understanding MDBR microbial diversity is crucial for optimizing reactor performance.