一株乳酸菌的鉴定、生物学特性与发酵培养基优化研究

Indentification of a Strain of Lactic Acid Bacteria and Study on Its Biological Properties and Optimization of Fermentation Medium

对一株饲用乳酸菌菌种SJ2-2进行菌株的16S rDNA分子生物学鉴定及生物学特性研究,进而采用响应面法优化其菌体生长培养基。结果表明,该菌为干酪乳杆菌,能够耐受2.5 g/L的牛胆盐和7%的NaCl,在pH为2.5～4.5的环境中仍然能够生长,且耐热能力较强。响应面优化分析得到的最优培养基组成为:工业葡萄糖36g/L,玉米浆50.4 mL/L,无水乙酸钠10.42 g/L,MgSO4 7H2O为0.2 g/L,MnSO4 H2O为0.01 g/L,FeSO4 7H2O为0.01 g/L,NaCl为0.01 g/L,吐温80为1 mL/L。在此最优条件下,干酪乳杆菌菌体生物量OD600值达到3.686,比优化前提高了81.8%。

A strain of lactic acid bacteria SJ2-2 applied in feed was identified by 16S rDNA sequencing and its biological characteristics were studied, then its culture medium for biomass growth was optimized by response surface methodology （RSM）. The results show that the Lactobacillus casei can tolerate a 2.5 g/L of bile salt and 7% NaCl, it still grow in theenvironment of pH 2.5-4.5. It has strong high temperature tolerance. The optimal medium for biomass growth by RSM was industrial glucose 36 g/L, corn steep liquor 50.4 mL/L, NaAc 10.42 g/L, MgSO4·7 H2O 0.2 g/ L, MnSO4·H2O 0.01 g/L, FeSO4·7 H2O 0.01 g/L, NaCl 0.01 g/L, lmL/L Tween-80. Under the optimal condition, the biomass 006oo of Lactobacillus casei SJ2-2 reaches 3.686, increased by 81.8% compared to the culture with original medium.