Glucose fermentation with biochar-amended consortium: microbial consortium shift

Area of Science:

• Microbiology
• Biotechnology
• Environmental Science

Background:

• Biochar, derived from various biomass sources, is explored for its potential applications in microbial processes.
• Understanding microbial community dynamics in fermentation is crucial for optimizing bioprocesses and product yields.

Purpose of the Study:

• To investigate the impact of different biochar types (rice husk, white popinee, bamboo, coconut) on microbial communities in glucose fermentation.
• To identify key microbial species enriched on biochar biofilms and their roles in fermentation pathways.

Main Methods:

• Glucose fermentation was conducted with the addition of four distinct biochar types.
• Microbial community analysis focused on identifying species enriched within the biofilms formed on biochar particles.
• Assessment of acid-producer and homoacetogen populations and their interactions was performed.

Main Results:

• Biochars served as effective biofilm carriers, enriching specific bacteria including *Sporolactobacillus spathodeae* and various *Clostridium sensu stricto* species.
• Fermentation significantly increased acid-producer populations within the biofilm.
• Homoacetogens (*Clostridium carboxidivorans*, *Clostridium drakei*) were identified, with biochars facilitating electron transfer in early fermentation stages.
• In long-term fermentation, heterotrophic bacteria dominated the biofilm, outcompeting acid-producers.

Conclusions:

• Biochar addition can modulate microbial community structure and enhance acid production in fermentation.
• Biochar acts as a crucial electron conductor, supporting homoacetogenesis in initial fermentation phases.
• Long-term microbial dynamics are influenced by competitive interactions, with heterotrophic bacteria eventually dominating.