Characterization of the antimicrobial substances produced by Bacillus pumilus D5 against bacterial aquaculture pathogens

10.29822/JFST.202209_49(3).0003

Mei-Ying Huang；Chia-Yi Shen；Hsuan-Ju Lin；Hong-Ting Victor Lin

Aquaculture ； antibacterial activity ； extracellular substances ； Bacillus ； antimicrobial peptides ； cell membrane

臺灣水產學會刊

49卷3期（2022 / 09 / 01）

173 - 183

英文

Bacterial infections have caused numerous diseases in the aquaculture industry, with Vibrios and Streptococci being the predominant pathogens, and the use of microorganisms, particularly Bacillus species, for the biocontrol of pathogens in aquaculture has gained significant attention. The extracellular substances of Bacillus pumilus D5 were shown to inhibit the growth the aquaculture pathogens Streptococcus agalactiae, Streptococcus iniae, Vibrio harveyi, and Vibrio parahaemolyticus. The extracellular antibacterial substances with the best antibacterial inhibition activity were harvested at the mid-stage stationary phase of B. pumilus D5 cultivation. The purified antibacterial substances were stable at pH 6-8, and the heat treatment at 80°C showed a limited reduction of their antimicrobial activity. Fluorescence microscopy analyses showed that the antimicrobial mechanism of the purified antibacterial substance from B. pumilus D5 might involve the disruption of bacterial cell membrane.