Co-Fermentation and Genomic Insights into Lactic Acid Bacteria for Enhanced Propionic Acid Production Using a Non-GMO...

Area of Science:

• Microbiology
• Biotechnology
• Biochemical Engineering

Background:

• Propionic acid (PA) is a valuable organic acid with diverse industrial applications.
• Current PA production relies heavily on petrochemical processes, driving demand for sustainable alternatives.
• Microbial biosynthesis offers a greener route, with lactic acid bacteria (LAB) showing promise.

Purpose of the Study:

• To develop a sustainable co-fermentation strategy for enhanced propionic acid (PA) biosynthesis using LAB.
• To investigate the 1,2-propanediol (PDO) pathway for PA production through metabolic cooperation.
• To identify and characterize LAB strains with complementary metabolic functions for PA and PDO synthesis.

Main Methods:

• Genome-based screening of LAB strains for PDO and PA pathway capabilities.
• Phenotypic assays to assess glycerol metabolism and acid tolerance.
• Co-culture fermentation trials using a fructose-sorbitol-glucose medium.

Main Results:

• Identified distinct LAB roles: some produce PDO (e.g., Carnobacterium maltaromaticum IBB3447), others convert PDO to PA (e.g., Levilactobacillus brevis IBB3735).
• Discovered novel PDO biosynthesis capability in C. maltaromaticum IBB3447.
• Achieved highest PA concentration (6.87 mM) and PDO accumulation (13.13 mM) in co-culture, demonstrating essential metabolic cooperation.

Conclusions:

• A novel LAB-based bioprocess for sustainable PA and PDO production was established.
• The process relies on cross-feeding interactions and valorization of waste streams.
• Findings support future optimization for circular bioeconomy applications.