Characterization and production optimization of a broad-spectrum bacteriocin produced by Lactobacillus casei KLDS 1.0338 and its application in soybean milk biopreservation

Abstract

This study aimed at characterization, production optimization, and assessing the biopreservative potential of a broad antimicrobial spectrum bacteriocin produced by Lactobacillus casei KLDS 1.0338, isolated from fermented sourdough in Northeast region of China. Ammonium sulfate precipitation and SP Sepharose TM fast flow were adopted to purify the bacteriocin, which resulted in a 7.43-fold purification and its molecular mass was estimated as 6.8 kDa. The bacteriocin was active over a wide pH range (2.0-12.0) and 2-12% NaCl and was heat and cold resistant (121°C for 30 min, and −20°C for 30 days). Optimization of culture conditions by response surface methodology indicated that the bacteriocin production was significantly enhanced than that of control (P < 0.05). Moreover, the lyophilized antimicrobial substance inhibited the growth of Staphylococcus aureus and Penicillium sp. in fermented soybean milk during storage at 4°C for 21 days. These results demonstrated that the bacteriocin from L. casei KLDS 1.0338 is a potential candidate for controlling microbial contamination and extending the shelf life of food products. ARTICLE HISTORY

Antimicrobial Activity of Bacteriocin Produced By a New Lactobacillus Curvatus sp.LAB-3H Isolated From Traditional Yogurt

“…A lag phase from zero to 4 h was observed, and the bacterium reaches the end of the exponential phase after 20 h of incubation, the strongest antimicrobial activities against S. aureus ATCC 25923 and E. coli ATCC 25922 was observed in the stationary phase at 24h of incubation. The approximate molecular mass of the bacteriocin produced by this strain was 6.8 kDa (Ma et al, 2020).…”

“…Jiaje Ma et al 2020 studied the growth dynamics and antimicrobial activity of L. casei KLDS 1.0338 against indicator strains. A lag phase from zero to 4 h was observed, and the bacterium reaches the end of the exponential phase after 20 h of incubation, the strongest antimicrobial activities against S. aureus ATCC 25923 and E. coli ATCC 25922 was observed in the stationary phase at 24h of incubation.…”

Growth Promoting Activity of Annona muricata L. Leaf Extracts on Lactobacillus casei

“…The demand for probiotics, such as L. casei , is increasing rapidly due to their impact on consumers’ health, so satisfying demand is a challenge [ 6 ]. Additionally, extracellular metabolic by-products of L. casei have been used as antagonist bacteria, bio-preservative, production of bacteriocin, and enzymes as clarification of juice [ 7 , 8 , 9 , 10 ].…”

A refined medium to enhance the antimicrobial activity of postbiotic produced by Lactiplantibacillus plantarum RS5

“…Fractional factorial design [FFD] and response surface methodology (RSM) are experimental strategies that gather the statistical techniques for designing experiments, evaluating the effects of independent variables and searching for the optimum conditions of variables to achieve a desirable goal 36 , 37 . This method has been successfully applied for the optimisation of metabolite production by microorganisms 34 , 38 , 39 , conditions of enzymatic hydrolysis 40 , amino acid productions 40 – 44 and parameters for food preservation and fermentation processes 45 . This study aimed to enhance the antimicrobial activity of the postbiotic RS5 by improving the culture density of L. plantarum RS5 and reduce the cost of the growth medium.…”