抗菌活性乳酸菌的篩選、優(yōu)化及其抗菌物質理化特性的研究.pdf

1、具有共生關系的酵母菌乳酸菌的篩選及對產信號分子 AI-2 的影響抗菌活性乳酸菌的篩選、優(yōu)化及其抗菌物質理化特性的研究Study on Screening and Optimation ofLactic acid bacteria and Charateristics of the bacteriocin申 請 人： 蘇日娜學科門類： 工 學學科專業(yè)： 食品科學研究方向： 食品生物技術指導教師： 雙全 教授論文提交日期：二〇一五年六月分類

2、號 TS252.1U D C 579學校代碼 10129學 號 2012209031Study on Screening and Optimation of Lactic acidbacteria and Charateristics of the bacteriocinAbstractThis experiment is to obtain a bacteriocin with a strong inhibitory effect a

3、ndbroad-spectrum through isolation and screening of lactic acid bacteria from fermentedfoods and the physiochemical charaterisitics of the bacteriocin was investigated andoptimized the fermentation conditions of the stra

4、in, discusses its application in feed. Theresults as follows.1. Strains with inhibitory effect from the test of 20 lactic acid bacteria isolated byDouble agar diffusion method, by which S1-4 was selected because of its s

5、ignificantinhibitory effect. The exhibited inhibitory activity against part of the Gram-positivebacteria and Gram-negative bacteria. And antibacterial spectrum was wide. 16S rDNAmolecular identification results shown tha

6、t the S1-4 was Lactobacillus pentosus(similarity of 99.7%).2. The characteristics of antibacterial substances of Lactobacillus pentosus S1-4,were tested for Escherichia coli 3301 as the indicator by the Double agar diffu

7、sionmethod. The results showed that the antibacterial activity of strain S1-4 was notdestroyed after treatment with papain, but destroyed after treatment with pepsin andtrypsin. This antibacterial substances of Lactobaci

8、llus pentosus S1-4 showed goodthermal stability and stable antibacterial activity under acidic conditions in pH 3.5~5.5.The inhibitory activity of this strain fermentation supernatant was not affected by somechemical age

9、nts and ultraviolet irradiation treatment.3. By single factor experiments and orthogonal experiments ， the optimalfermentation condition of antibacterial substance produced by Lactobacillus pentosusS1-4 and antibacterial

10、 spectrum of antibacterial compounds was studied. The resultshowed that the optimum inoculation quantity was 2%, initial fermentation pHwas5.5,culturing at 30 ℃ for 26 hours. The diameter of inhibitory activity ofLactoba

11、cillus pentosus under the optimum broth was (30.08±0.69) mm , the optimizedbacteriostatic activity increased 1.19 times.4. The purification of the antibacterial substances of Lactobacillus pentosus S1-4showed that t