State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
College of Food and Biological Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou, China.
Microb Cell Fact. 2022 Sep 19;21(1):194. doi: 10.1186/s12934-022-01912-3.
Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have attracted increasing interest because of their potential as natural bio-preservatives.
We screened a large number of Bacillus thuringiensis strains and isolated one strain (B. thuringiensis P86) with antimicrobial activity against several foodborne pathogens. Three novel leaderless bacteriocins, including thucin A1, thucin A2 and thucin A3, were purified and identified from the culture supernatant of B. thuringiensis P86, whose molecular masses were 5552.02, 5578.07 and 5609.06 Da, respectively. Thucin A1 was then selected as a representative to be tested, and it exhibited potent inhibitory activity against all tested gram-positive bacteria. More importantly, thucin A1 showed stronger antimicrobial activity than nisin A against two important foodborne pathogens Bacillus cereus and Listeria monocytogenes. In addition, thucin A1 exhibited strong acid-base adaptability (pH 2-11), high endurance to heat, good stability to trypsin and pepsin, no hemolysis activity and cytotoxicity, and could effectively inhibit or eliminate Bacillus cereus and Listeria monocytogenes in skim milk.
Our findings indicate that these novel leaderless bacteriocins are potentially promising food biopreservatives.
由于化学防腐剂的有害影响，人们对更安全、更健康和天然的生物防腐剂的需求不断增加。由于其作为天然生物防腐剂的潜力，细菌素引起了越来越多的关注。
我们筛选了大量苏云金芽孢杆菌菌株，并从中分离到一株具有抗几种食源性致病菌活性的菌株（苏云金芽孢杆菌 P86）。从苏云金芽孢杆菌 P86 的培养上清液中纯化并鉴定了三种新型无信号肽细菌素，分别为 thucin A1、thucin A2 和 thucin A3，它们的分子量分别为 5552.02、5578.07 和 5609.06 Da。然后选择 thucin A1 作为代表性物质进行测试，它对所有测试的革兰氏阳性菌均表现出很强的抑制活性。更重要的是，与乳链菌肽 A 相比，thucin A1 对两种重要的食源性致病菌蜡样芽孢杆菌和单核细胞增生李斯特菌表现出更强的抗菌活性。此外，thucin A1 具有较强的酸碱适应性（pH 2-11）、对热的耐受性高、对胰蛋白酶和胃蛋白酶稳定、无溶血活性和细胞毒性，可有效抑制或消除脱脂乳中的蜡样芽孢杆菌和单核细胞增生李斯特菌。
我们的研究结果表明，这些新型无信号肽细菌素具有成为潜在的有前途的食品生物防腐剂的潜力。
