一株海洋源细菌素产生菌筛选及细菌素性质研究

Screening for bacteriocin-producing bacteria and study of its bacteriocin properties

化学食品防腐剂潜在的副作用使其使用受到越来越严峻的挑战,微生物产天然食品防腐细菌素成为关注的热点。本研究以L.monocytogenes、E.coli、S.aureus、B.subtilis、V.parahemolyticus、A.niger为指示菌,以牛津杯法评价抗菌活性,以南海海洋动物肠道作为分离材料,通过抗菌作用的排酸实验、过氧化氢排除实验以及蛋白酶敏感实验进行细菌素产生菌的筛选,并进行了细菌素物质的热稳定性与酸稳定性的研究。筛选出1株具有抗菌活性强,抗菌谱广的细菌素产生菌A0705,其发酵液在-20～100℃处理30 min后,再在pH2.5～11.5的范围内37℃温浴2 h,仍保持较稳定的抗菌活性,经16S r DNA序列同源性比对及系统发育树分析,鉴定菌株A0705为芽孢杆菌（Bacillus sp）,该菌是1株值得进一步研究与开发的海洋源细菌素产生菌。

The use of chemical food preservatives are facing more and more severe challenges due to their potential side effects on human health. The bacteriocin produced from microbes,as the natural food preservative,has attracted widespread attention. Therefore,the study was carried out on the screening for bacteriocin- producing bacteria from marine environment. The experiment empolyed L. monocytogenes,E. coli,S. aureus,B. subtilis,V. parahemolyticus,and A. niger as indicator bacteria,used Oxford cup method to determine the antimicrobial activity,and adopted marine animals intestinal from the south China sea as microbial isolation materials. The screening of bacteriocin producing bacteria were performed by eliminating inhibitory effects of organic acid and H_2O_2,and observing bacteriocin sensitivity to protease. Moreover,the bacteriocin stabilities to thermal,acid and alkali were also studied. A bacteriocin- producing strain A0705 with high antibacterial activity and broad spectrum inhibition for indicator bacteria was obtained. Its culture supernatant still remained strong antibacterial activity after heating treatment at- 20 ～ 100 ℃ for 30 min,and then acid and alkali treatments at pH 2. 5 ～ 11. 5 for 2 h at 37 ℃. Strain A0705 was identified as Bacillu sp. by comparative analysis of 16 SrDNA gene sequence homology and phylogenetic tree. Strain A0705 will be a potential bacteriocin producing bacteria for using as a food bio- preservative.