Enhanced phenyllactic acid production from grass carp viscera hydrolysate using engineered Pediococcus acidilactici

Area of Science:

• Biotechnology
• Microbial Engineering
• Metabolic Engineering

Background:

• Phenyllactic acid (PLA) is a valuable compound with diverse applications.
• Lactic acid bacteria (LAB) are promising hosts for microbial production of PLA.
• Improving PLA yield in LAB is crucial for cost-effective industrial production.

Purpose of the Study:

• To enhance phenyllactic acid (PLA) production in Pediococcus acidilactici.
• To investigate the role of aromatic amino acid transaminase (araT) and l-lactate dehydrogenase (ldhL) genes in PLA biosynthesis.
• To optimize fermentation conditions for maximizing PLA yield.

Main Methods:

• Cloning and expression of araT and ldhL genes in Pediococcus acidilactici.
• Construction of plasmid-based and chromosomal integration expression strains.
• Quantitative analysis of PLA production using modified MRS and G2EH media.
• Optimization of medium composition and fermentation parameters using response surface methodology.

Main Results:

• Overexpression of araT and ldhL genes significantly increased PLA yield in engineered LAB strains.
• The La52TL strain achieved a PLA yield of 616.62 mg/L in modified MRS medium, an 11.56% increase.
• PLA production in G2EH medium using the La52TL strain was 24.94% higher than the parental strain.
• Response surface methodology optimization led to a further increase in PLA yield to 337.86 mg/L.

Conclusions:

• Overexpression of araT and ldhL is an effective strategy to enhance PLA production in LAB.
• Engineered LAB strains show potential for efficient PLA biosynthesis.
• This study provides a promising approach for the valorization of fish processing by-products into PLA.