具有降低牛乳中β-乳球蛋白抗原性能力的乳酸菌的筛选及性质研究

Study on screening and characteristics of lactic acid bacteria with potential to reduce antigenic response of β-lactoglobulin in skim milk

以乳清蛋白为唯一氮源改良MRS培养基,从生牛乳中分离得到一株降解β-乳球蛋白抗原性能力较好的乳酸菌株,最高降解率达到87%,经形态观察和16S rDNA序列分析,该菌被鉴定为干酪乳杆菌L.casei WPC09。L.casei WPC09菌株的最低生长温度为20℃,最高生长温度为45℃,最适生长温度为35～37℃;最低和最高生长起始pH分别为pH4.0和9.0,最适起始生长pH为6.4～6.5。菌株6h左右进入对数生长期,16h达到稳定生长期,24h后进入衰亡期。菌株的胆盐最高耐受浓度为质量分数0.09%;NaCl最高耐受浓度为质量分数10%。

A strain of lactic acid bacteria with high reduction of the β-lg antigenity of skim milk was isolated from raw milk,and it could reduce 87% of β-lg antigenity. The morphology, 16S rDNA sequence of strain WPC09 were studied and the results showed that characteristics of this strain were essentially consistent with Lactobacillus casei.The minimum growth temperature of the strain L.casei WPC09 was 20℃,the maximal growth temperature was 45℃,and the optimum was 35-37℃, as to the pH, the minimum and the maximal were pH 4.0 and 9.0, and the optimum was 6.4~6.5.The growth curve of L.casei WPC09 showed that the lag phase ranges from 0-6h,and then enters exponential phase till 16h when it reaches the stationary phase, finally, the death phase after 24h.And the maximal growth concentration of bible salt was 0.09% ,and that of the NaCl was 10%.