柿子醋醪中优良乳酸菌的筛选及其耐受性和功能性分析

Screening of Superior Lactic Acid Bacteria in Persimmon Vinegar Broth and Analysis of Its Tolerance and Function

为了从柿子醋醪中获得适合植物基质发酵的具有产酸能力强、耐受性能好和功能性强的乳酸菌。以自然发酵的柿子醋醪为目标乳酸菌供体,采用MRS液体培养基培养、溶钙圈法初步筛选,分离得到5株乳酸菌菌株。通过对菌株的产酸能力、耐受性、抗氧化能力以及产β-葡萄糖苷酶水平进行测定,对综合性能较强的两株乳酸菌菌株进行形态学及16S rDNA分析。结果表明:经筛选鉴定得到的两株优良乳酸菌为嗜酸乳杆菌(Lactobacillus acidophilus)和植物乳杆菌(Lactobacillus plantarum)。两株乳酸菌菌株产酸能力分别为2.00、2.24 g/100 mL;最低耐受p H均为1.5;最高耐受乙醇浓度均为10%;胆盐耐受性均为1%、最高耐受NaCl浓度均为7%;对ABTS^(+)、DPPH、O^(2-)自由基清除能力分别为65.12%和62.26%,77.42%和68.89%,93.76%和87.89%;产β-葡萄糖苷酶能力分别为26.37,30.27 IU/L。本文从柿子醋醪中获得用于植物基质发酵的具有较强生物学性能的两株乳酸菌菌株,该菌株为益生菌的开发提供了菌种资源。

In order to obtain lactic acid bacteria(LAB)with a strong acid production capacity,good tolerance,and high function from persimmon vinegar broth,which is suitable for plant substrate fermentation.Using the persimmon vinegar broth naturally fermented as a source of lactic acid bacteria,five strains were isolated using MRS liquid culture medium and calcium-dissolving circle methods.The abilities of producing acid,tolerance,antioxidant andβ-glucosidase production of the 5 LABs were measured,the morphology and 16S rDNA identification of the screened two LABs with stronger comprehensive performance were analyzed.Based on the results of the screening,Lactobacillus acidophilus and Lactobacillus plantarum were identified as two excellent strains of lactic acid bacteria.Both lactic acid bacteria produced acid at a rate of 2.00 and 2.24 g/100 mL,respectively.Among the pH tolerances,the lowest was 1.5,the highest was 10%for ethanol,1%for bile salts,and 7%for NaCl.The scavenging abilities of screened two LABs on ABTS^(+),DPPH,O^(2-)free radicals were 65.12%and 62.26%,77.42%and 68.89%,93.76%and 87.89%,respectively.The production ofβ-glucosidase were 26.37 and 30.27 IU/L.In this paper,the two LABs strains with strong biological properties were obtained from persimmon vinegar broth for plant substrate fermentation,which could provide strain resources for the development of probiotics.