传统发酵豆腐酸浆中高产酸乳酸菌的分离鉴定及特性分析

该研究从采集于全国具有代表性的6大豆腐产地的7种豆腐酸浆老汤中分离筛选各样品中高产酸乳酸菌，通过形态观察及分子生物学技术对其进行鉴定，并对其产酸特性、耐酸特性及耐盐特性进行研究。结果表明，分离筛选到7株产酸性能优良的乳酸菌，并鉴定菌株L2-03、L3-01、L6-07与L7-01为玉米乳杆菌（Lactobacillus zeae），菌株L1-02、L8-03与L10-01为副干酪乳杆菌（Lactobacillus paracasei）。除菌株L6-07外，6株乳酸菌均能产草酸、酒石酸、丙酮酸、乳酸、乙酸、富马酸及琥珀酸共7种有机酸，其中乙酸与乳酸为主要有机酸。产酸能力方面，菌株L6-07产酸量最高，达25.69 g/L，产酸能力最强；耐酸性方面，菌株L6-07在pH 2.5的酸性条件下仍能保持生长，耐酸性最好；耐盐性方面，菌株L1-02在5%NaCl条件下表现出较强的耐受性，耐盐性最强，菌株L6-07次之。

Isolation,identification and characterization of high yield acid-producing lactic acid bacteria from traditionally fermented soy-whey

The high yield acid-producing lactic acid bacteria were isolated and screened from 7 fermented soy-whey collected from 6 representative tofu producing areas in China, and identified by morphological observation and molecular biological technique. At the same time, the acid-producing characteristics, acid and salt tolerance ability of the selected strains were studied. The results showed that 7 strains of lactic acid bacteria with excellent acid-producing performance were isolated, the strain L2-03, L3-01, L6-07 and L7-01 were identified as Lactobacillus zeae, and the strain L1-02, L8-03 and L10-01 were identified as Lactobacillus paracasei. In addition to strain L6-07, all the 6 strains of lactic acid bacteria could produce 7 kinds of organic acids, including oxalic acid, tartaric acid, pyruvate, lactic acid, acetic acid, fumaric acid and succinic acid, among which acetic acid and lactic acid were the main organic acids. In terms of acid production capacity, the strain L6-07 had the highest acid-producing capacity, and reached 25.69 g/L. In terms of acid tolerance ability, the strain L6-07 had the strongest acid resistance, which could still maintain growth under the acidic condition with pH 2.5. In terms of salt tolerance, the strain L1-02 had the strongest salt tolerance, which showed strong tolerance under 5% NaCl condition, followed by the strain L6-07.