Isolation of a Strain from Bacillus spp. with Broad Spectrum of Antimicrobial Activity and Structural Identification of Bioactive Compounds as well as their Biopreservative Application

• Main Authors: Jen -Ni Chen, 陳珍妮
• Other Authors: Chin-Shuh Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/89773999585102681384

博士 === 國立中興大學 === 食品暨應用生物科技學系所 === 103 === Recently, drugs and chemical preservatives are generally used in food products resulting in many serious problems in food safety. In addition, antibiotics overuse lead to evolution of Multiple drugs-resistant strains such as Methicillin-resistant Staphylococcus Aureus (MRSA) and Vancomycin-resistant strains. Futhermore, molds are able to proliferate in food to produce mycotoxin such as alpha-toxin. Many studies have demonstrated that mycotoxin can induce cell mutation leading to induction of hepatic tumor. At present, many studies focused on natural products to replace chemical preservatives against bacteria and molds. The three Bacillus lipopeptides, surfactins, iturins and fengycins, have broad anti-pathogens activities including bacteria and molds. Today, our study successfully purified non-toxic biopreservative from GRAS Bacillus. In addition, our study added the non-toxic biopreservative in food and cosmetics to develop a natural biopreservative and skin-care products. In this study, candidate strain isolated from chicken intestines was cocultured with Asp. niger by using spot on the lawn method, and the candidate bacteria strain with anti-molds activity were analyzed and isolated. Furthermore, the candidate bacterial strain and its antimicrobial gene were identified by PCR method. Next, we extracted the antimicrobial lipopeptides by aicd precipitation , then analyzed the lipopeptide structure by using LC-ESI-Mass/Mass. After that, the antimicrobial spectrum of the CFS products produced from bacillus amyloliquefaciens JN68 were determined by various indicators. The preservative activities of food and cosmetics containing CFS crude extracts were futher analyzed in this study. Our results showed that CFS extracts successfully inhibit growh of various bacteria and molds including MRSA、Vancomycin-resistant E.coli, EIEC, alpha-toxin producing molds、Helicobacter pylori、pathogen、food spoilage bacteria、clinical skin dermatophyte. On the other hand, the gene and structure analysis data showed that the activity compounds from CFS crude extracts are classified into three lipopeptides families，surfactin，iturin and fengycin. Importantly, food and skin-care products with this CFS extracts have obvious biopreservative activities. Therefore, our results indicated that CFS extracts produced from Bacillus amyloliquefaciens JN68 have great potential to replace chemical preservative to act as biopreservative.