Microbial community composition and dynamics in high-temperature biogas reactors using industrial bioethanol waste as...

Area of Science:

• Biotechnology
• Environmental Science
• Microbiology

Background:

• Stillage, a byproduct of bioethanol production, is a potential feedstock for biogas generation in biorefineries.
• Optimizing biogas production from lignocellulosic biomass requires understanding microbial community dynamics.

Purpose of the Study:

• To investigate the microbial community structure and dynamics in a continuous stirred tank reactor (CSTR) fed with stillage.
• To analyze the impact of process perturbation (acidification) on microbial populations during biogas production.

Main Methods:

• Cultivation of microbial community in a CSTR using thin stillage as a mono-substrate.
• 16S rRNA gene amplicon sequencing (V2-V3 regions) to analyze bacterial and archaeal communities.
• Controlled increase of organic loading rate to induce acidification and observe population shifts.

Main Results:

• Predominance of Bacteria from Thermotogaceae and Elusimicrobiaceae families was observed.
• Dominant methanogens included acetoclastic Methanosaetaceae and hydrogenotrophic Methanobacteriaceae.
• Acidification led to a decrease in bacterial abundance but stable archaeal numbers, with increased Methanosaetaceae and decreased Methanobacteriales.

Conclusions:

• Stillage is a viable substrate for biogas production, supporting specific microbial communities.
• Process acidification can induce persistent shifts in microbial community composition.
• Uncommon bacterial families play significant roles in biogas production processes.