自然发酵椰子水中拮抗乳酸菌筛选鉴定及抑菌特性

Screening and Identification of Antagonistic Lactic Acid Bacteria from Fermented Coconut Water and Its Antibacterial Properties

该文以来自于自然发酵椰子水中生长良好的乳酸菌为研究对象,以来自于病死肉鸡的耐药性致病菌为指示菌进行抑菌活性初筛,再进行耐受性复筛,得到一株优良菌株A32,经鉴定为发酵乳杆菌(Lactobacillus fermentum)。A32在椰子水中能保持旺盛生长1 d~4 d,活菌数维持8 lg cfu/mL~9 lg cfu/mL,能大量产酸,最低pH值为3.55、总酸最高达17.09 g/L。蛋白酶和高温处理对其抑菌活性几乎不产生影响,上调pH值至5.0时其抑菌活性消失。抑菌活性与其总酸含量呈显著正相关(p<0.05),推测A32所产抑菌物质主要为有机酸类,具体种类有苹果酸、柠檬酸和乳酸等,其中苹果酸比例达64%以上。推测菌株A32在椰子水中高活性抑菌作用可能与其较低的pH值、较高的总酸和苹果酸含量有关。

In this study,well growing lactic acid bacteria from naturally fermented coconut water were used as the research test material,and drug-resistant pathogens from dead broilers were used as the indicator bacteria for primary screening of antibacterial activity and re-screening of tolerance.A superior strain A32,which was identified as Lactobacillus fermentum,was obtained.A32 could grow vigorously in coconut water from 1 to 4 days,and viable bacteria count was maintained at 8 lg cfu/mL-9 lg cfu/mL.Large amount of acid,with the lowest pH of 3.55 and the highest total acid of 17.09 g/L,was produced.Protease and high temperature treatments had little antibacterial effect,and antibacterial activity disappeared when pH value was raised to 5.0.There was a significant positive correlation between antibacterial activity and total acid content(p<0.05).Therefore,it was inferred that the main antibacterial substances produced by A32 were organic acids,and they include malic acid,citric acid,and lactic acid,among which the proportion of malic acid was more than 64%.It was speculated that the high antibacterial activity of A32 in coconut water might be related to its low pH value,high total acid and malic acid contents.