Optimizing Garvicin Q Bacteriocin Production Using Corynebacterium glutamicum
Bacteriocins, antimicrobial peptides used in food preservation and as alternatives to antibiotics, have garnered interest for their potential as microbiome modulators.
Recently, researchers at the University of Ulm, led by Dr. Christian U. Riedel, established Corynebacterium glutamicum as an effective host for producing various bacteriocins, including garvicin Q (GarQ).
Initially, GarQ production by C. glutamicum reached approximately 7 mg/L in early fermentations, limited by peptide adsorption to the bacterial envelope under neutral pH conditions. To enhance production, the team introduced CaCl2 and Tween 80 supplements, reducing adsorption and boosting GarQ yield to about 15 mg/L. However, Tween 80's use also reduced GarQ activity over time.
Further optimization involved transferring production to a HtrA-deficient C. glutamicum strain, nearly quadrupling GarQ titers to close to 40 mg/L. Low-aeration conditions further improved yields to approximately 100 mg/L, a significant enhancement over previous methods.
Moreover, synthetic variants of GarQ, such as GarQM5F (methionine to phenylalanine substitution at position 5), demonstrated increased efficacy against pathogens like Lactococcus lactis and Listeria monocytogenes.
Dr. Riedel will present an overview on the identification, production and application of bacteriocins at the Targeting Microbiota 2024 conference. Learn more about Dr. Riedel's talk.
