泡菜中抑菌性芽孢杆菌的筛选及其细菌素理化特性

目的:本文旨在从传统发酵泡菜中筛选有抑菌活性的芽孢杆菌。方法:采用热处理和抑菌板双重筛选出具有抑菌活性的芽孢杆菌,通过生理生化反应和16S rDNA序列分析鉴定分离菌株,研究蛋白酶、温度和pH对芽孢杆菌无细胞上清液抑菌活性的影响。结果:从泡菜中筛选出具有较强抑菌活性的芽孢杆菌PC-2,经鉴定为蜡样芽孢杆菌(Bacillus cereus)。PC-2无细胞上清液对木瓜蛋白酶、胰蛋白酶、链霉蛋白酶敏感,对淀粉酶和脂肪酶不敏感;经70、80、90℃处理30 min后,对大肠杆菌和酵母菌的拮抗活性基本不变;在pH2.0~8.0范围内保持其抑菌活性;对大肠杆菌、金黄葡萄球菌、酵母菌及链霉菌具有广泛的抑菌作用;结论:从泡菜中筛选出的蜡样芽孢杆菌PC-2对革兰氏阳性菌和革兰氏阴性菌具有较强抑制作用,初步分析抑菌活性物质为细菌素类,为生物保鲜新品种的开发奠定基础。

Screening of Bacillus with Antimicrobial Activity from Pickles and Physicochemical Characteristics of Bacteriocin

Objective:To screen Bacillus strain with antimicrobial activity from traditional fermented pickles. Methods:Bacillus strains with antimicrobial ability were double screened by heat treatment and bacterial culture plates. The strain was identified by biochemical tests and 16S rDNA sequence analysis. The antimicrobial activity substance from Bacillus was analyzed using protease sensitivity test,thermal treatment test and acid and alkaline test. Results:Strain PC-2 with outstanding antimicrobial activity from pickles was identified as Bacillus cereus. The cell-free supernatants from Bacillus was sensitive to papain,trypsin,prenase,but not to amylase and lipase. The antimicrobial activity to Escherichia coli and Streptomyces was stable after heat treatment 30 min with 70,80,90℃,and was effective within pH2.0~8.0. The cell-free supernatants from Bacillus PC-2 had broad spectrum of inhibition against Escherichia coli,Staphylococcus aureus,Saccharomycete and Streptomyces. Conclusion:Bacillus cereus PC-2 with strong antimicrobial activity against gram-positive bacterium and gram-negative bacterium was screened from fermented pickles. The antibacterial substance produced by strain PC-2 was preliminarily determined as bacteriocins. It lays the foundation for the development of new varieties of biological preservation.