Isolation,Purification and Antibacterial Properties Analysis of Bacteriocins Derived from Lactobacillus acidophilus LA18

LIN Wan-hua; DU Zhe; OU Hao; XUAN Jing-hao; ZHANG Wen; JIANG Shun-jin; HUANG Qin-geng; HUANG Wei

doi:10.13651/j.cnki.fjnykj.2025.10.009

Abstract：In order to solve the issue of diarrhea in farmed animals and develop the green,safe and efficient alternatives to antibiotics in feed additives,Lactobacillus acidophilus LA18(GDMCC 62222),which was isolated and preserved independently,was used as the research object.A bacteriocin was isolated and purified from the fermentation broth of Lactobacillus acidophilus LA18(GDMCC 62222)through specific culture media and fermentation conditions.Then,its molecular weight was determined by using the high-resolution mass spectrometry,and its minimum inhibitory concentration(MIC)and antibacterial spectrum were evaluated by using the microbroth dilution method and the agar diffusion method.Additionally,the stability of the bacteriocin under different pH and temperature conditions was investigated,and its hemolytic activity was detected to assess its biological safety.The results showed that the bacteriocin had a molecular weight of approximately 3320 Da and exhibited significant inhibitory activity against Staphylococcus aureus(MIC:0.4 μg·mL-1),while showing no significant inhibitory effect on the common probiotics such as Bacillus subtilis,Enterococcus faecium,and Lactobacillus plantarum.It maintained good stability under pH conditions＜8.0,but was easily inactivated in strong alkaline environments.It remained stable after treatment at 70℃,80℃,and 90℃for 10 minutes,with a hemolysis rate of less than 5%,showing good environmental tolerance and biological safety.This study provided new ideas for the development of novel feed additives and the improvement of animal gut health by systematically evaluating the biological functions and safety characteristics of the bacteriocin produced by Lactobacillus acidophilus LA18.