Efficient butyrate production from rice straw in an optimized cathodic electro-fermentation process.

Area of Science:

• Biotechnology
• Renewable Energy
• Biorefining

Background:

• Butyrate production from renewable biomass offers a sustainable alternative to fossil fuels, addressing climate change.
• Lignocellulosic biomass, like rice straw, is an abundant and underutilized resource for chemical production.

Purpose of the Study:

• To optimize key operational parameters for efficient butyrate production from rice straw using cathodic electro-fermentation (CEF).
• To evaluate the performance of CEF in both batch and fed-batch modes for maximizing butyrate yield and concentration.

Main Methods:

• Optimization of cathode potential, pH, and initial substrate dosage for the CEF process.
• Fermentation experiments conducted in batch and fed-batch modes using a mixed microbial culture.
• Microbial community analysis to identify key butyrate-producing bacteria.

Main Results:

• Optimal conditions for batch CEF were determined as -1.0 V (vs Ag/AgCl), pH 7.0, and 30 g/L rice straw, yielding 12.50 g/L butyrate.
• Fed-batch operation significantly increased butyrate production to 19.66 g/L, with a yield of 0.33 g/g-rice straw.
• Enrichment of butyrate-producing bacteria (Clostridium clusters XIVa and IV) to 58.75% contributed to high butyrate levels.

Conclusions:

• Cathodic electro-fermentation is a viable and promising approach for efficient butyrate production from lignocellulosic biomass.
• Further improvements in butyrate selectivity are needed for enhanced process efficiency.
• The study highlights the potential of CEF in sustainable chemical production from renewable resources.