Efficient caproate production from lignocellulose via single-step electro-fermentation platform without organic...

Area of Science:

• Biotechnology
• Environmental Microbiology
• Sustainable Chemistry

Background:

• Microbial caproate production faces challenges with sterile conditions and organic electron donors.
• Sustainable and eco-friendly bioproduction methods are in high demand.

Purpose of the Study:

• To develop a single-step electro-fermentation process for caproate production directly from rice straw.
• To optimize the electro-fermentation process using a neutral red mediator and bioaugmentation.

Main Methods:

• Utilized a single-step electro-fermentation (EF) process with a mixed microbial culture.
• Investigated the effect of applied potential (-0.8 V) and neutral red (NR) mediation.
• Employed bioaugmentation with a chain-elongation microbial consortium.

Main Results:

• Achieved 2.4 g/L caproate at 0.2 g/g yield and 26.6% selectivity in the NR-mediated EF system.
• Long-term operation in EF+NR system increased caproate to 5.3 g/L (0.2 g/g yield, 34.2% selectivity).
• Bioaugmented EF+NR system yielded 9.1 g/L caproate (0.3 g/g yield, 41.5% selectivity).

Conclusions:

• Electro-fermentation offers a sustainable route for caproate production from waste biomass.
• Bioaugmentation enhances microbial community function, electron transfer, and caproate production efficiency.
• This approach provides a cost-effective strategy for caproate bioproduction.