【作者】 王旎； 袁磊； 赵慧莹； 何国庆；

【Author】 Wang Ni;Yuan Lei;Zhao Huiying;He Guoqing;College of Biosystems Engineering and Food Science,Zhejiang University;

【机构】 浙江大学生物系统工程与食品科学学院；

【摘要】 奶粉加工过程中由嗜热菌形成的生物膜结构是令全世界乳制品行业棘手的难题,它不仅会损害乳制品品质,还会造成食品安全问题。目前,革兰氏阴性菌生物膜信号分子的研究较为成熟,但革兰氏阳性菌的相关研究非常匮乏,而市售奶粉产品中分离出的嗜热菌均为革兰氏阳性菌。本文以奶粉产品中分离出的33株嗜热芽孢菌为研究对象,对其可能产生的群体感应信号分子的种类进行了探究。以根癌农杆菌A136为报告菌株进行平板划线,并经HPLC-MS检测,发现各菌株均不产生N-酰基高丝氨酸内酯类(AHLs)信号分子。以哈氏弧菌BB170为报告菌株检测菌液荧光强度,发现各菌株均可产生不同活性的种间交流AI-2类信号分子,其中一株嗜热脂肪土芽孢杆菌(Geobacillus stearothermophilus)的相对活性最高,达24.33%±2.95%。经Superdex peptide10/300 GL凝胶过滤层析柱分离,发现一株地衣芽孢杆菌(Bacillus licheniformis)发酵液中6 kD左右的组分,使其新鲜菌液的生物膜形成能力提高了65.75%,这可能与嗜热菌分泌到胞外的自诱导肽类(AIP)信号分子的作用有关。更多还原

【Abstract】 The biofilm formed by thermophilic aerobic sporeforming bacteria in the processing of milk powder is a worldwide difficult problem to the dairy industry.It will not only ruin the quality of dairy products,but also cause food safety problems.At present,researches on biofilm autoinducers of Gram-negative bacteria are relatively abundant,but very scarce on Gram-positive bacteria,moreover,all of the thermophilic bacteria we isolated from commercially available milk powder products are Gram-positive.In this study,the types of possible autoinducers of 33 thermophilic bacteria strains isolated from milk powder were investigated.Using Agrobacterium tumefaciens A136 as a reporter strain,tested by spreading plates and HPLC-MS method,it is found that none of the strains produced N-acylhomoserine lactone(AHLs) signaling molecules.Luminescence intensities of the zymotic fluid were determined with the exist of Vibrio Harveyi BB170 as a reporter strain,and it is indicated that all the strains could produce interspecific communication signaling molecule AI-2 with different activity,among which,a Geobacillus stearothermophilus strain had the highest relative activity,reaching 24.33%±2.95%.After separation by Superdex peptide 10/300 GL gel filtration chromatography column,it showed the 6 kD composition in the zymotic fluid of a Bacillus licheniformis strain increased the biofilm formation ability of its own fresh bacterial fluid by 65.75%,which may be related to the autoinducing peptide(AIP) signaling molecules secreted by the thermophilic bacteria cells.更多还原