新疆哈族奶酪中产蛋白酶非发酵剂乳酸菌的筛选及其系统发育分析

Screening of protease-producing non-starter lactic acid bacteria from Xinjiang Kazak cheese and its phylogenetic analysis

以采集10份新疆塔城地区哈萨克族牧民自制的奶酪为原料,用改良的ROGOSA和MRS两种培养基对其分离纯化,共筛选出43株菌种,其中球菌32株,杆菌11株。对筛选出的菌株进行产蛋白酶和菌株自溶能力测定,结合生理生化特性和16S r DNA序列同源分析和建立系统发育树分析,对挑选出的10株优势菌进行了菌株分子生物学鉴定,鉴定结果表明:菌株R6-6自溶度最高,为42.32%;而自溶度最低的菌株为R4-4,达到6.21%;菌株R2-2、R4-2、R4-7为表皮葡萄球菌(Staphylococcus epidermidis);菌株R3-5、R10-6为乳酸片球菌(Pediococcus acidilactici);菌株R3-2为戊糖片球菌(Pediococcus pentosaceus);菌株R6-6为干酪乳杆菌(Lactobacillus casei);菌株R9-5、R9-6为鼠李糖乳杆菌(Lactobacillus rhamnosus)。其中产蛋白酶的最优势非发酵剂乳酸菌(NSLAB)菌株为乳酸片球菌(P.acidilactici)。

A total of 43 strains were screened from 10 pieces of the Kazak homemade cheese in Xinjiang Tacheng prefecture by improved ROGOSA and MRS medium, in which 32 strains were Coccus and 11 strains were Bacillus. The ability of protease-producing and autolysis of strains were determined. Combined with physiological and biochemical characteristics, 16S rDNA sequence homology and phylogenetic tree analysis, the 10 dominant strains selected were identified by molecular biology method. The results showed that the autolysis rate of strain R6-6 was the highest of 42.32%, and the autolysis rate of strain R4-4 was the lowest of 6.21%. Strain R2-2, R4-2 and R4-7 were identified as Staphylococcus epidermidis, strain R3-5 and R10-6 were identified as Pediococcus acidilactici, strain R3-2 was indentified as Pediococcus pentosaceus, strain R6-6 was indentified as Lactobacillus casei, and strain R9-5 and R9-6 were identified as Lactobacillus rhamnosus, in which the non-starter lactic acid bacteria （NSLAB） with high protease-producing was identified as P. acidilactici.