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Propionic acid production from corn stover hydrolysate by Propionibacterium acidipropionici
Xiaoqing Wang1, Davinia Salvachúa1, Violeta Sànchez I Nogué1
1National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA.
Biotechnology for Biofuels
|August 22, 2017
Summary
This study optimized propionic acid (PA) production from corn stover hydrolysate using Propionibacterium acidipropionici. Fermentation strategies significantly increased PA titers and productivity, demonstrating its feasibility for biorefineries.
Area of Science:
- Biotechnology
- Industrial Microbiology
- Sustainable Chemistry
Background:
- Economic viability of biorefineries relies on producing value-added chemicals from lignocellulosic hydrolysates.
- Propionic acid (PA) is a key C3 building block chemical with significant industrial applications.
Purpose of the Study:
- To investigate and optimize the production of propionic acid (PA) from corn stover hydrolysate.
- To enhance PA titer, rate, and yield using the bacterium Propionibacterium acidipropionici.
Main Methods:
- Optimization of fermentation parameters including gas sparging (N2 vs. CO2), hydrolysate concentration, nitrogen sources (yeast extract), and neutralization agents (NH4OH).
- Evaluation of batch and fed-batch fermentation strategies, including continuous vs. pulsed feeding.
- Implementation of high cell density fed-batch fermentation to maximize productivity.
Main Results:
- Optimized batch fermentation achieved 30.8 g/L PA titer with 0.40 g/L/h productivity, minimizing lactic acid.
- Fed-batch fermentation with continuous hydrolysate feeding and high yeast extract concentrations increased PA titers to 62.7 g/L.
- High cell density fed-batch fermentation yielded peak PA titers of 64.7 g/L with 2.35 g/L/h productivity during the batch phase.
Conclusions:
- Media composition and fermentation strategy are crucial for improving propionic acid production from lignocellulosic biomass.
- This study confirms the feasibility of producing propionic acid from corn stover hydrolysate, supporting biorefinery development.
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