复合益生菌发酵培养基与冻干保护剂的筛选

Screening of compound probiotic fermentation medium and freeze-drying protective agents

为实现对枯草芽孢杆菌(Bacillus subtilis)、格式乳球菌(Lactococcus garvieae)、施氏假单胞菌(Pseudomonas stutzeri)和酵母菌(Yeast)4株水产养殖益生菌菌株的共发酵培养,进行了单一无机盐去除实验和冻干保护剂筛选实验.结果显示:①4株益生菌复合发酵培养基的具体成分包括葡萄糖20 g、蛋白胨10 g、牛肉浸粉5 g、酵母粉5 g,硫酸镁0.1 g、柠檬酸氢二铵2 g、磷酸氢二钾2 g、硫酸锰0.05 g、吐温801 mL、蒸馏水1000 mL;②枯草芽孢杆菌只有在去除乙酸钠的培养基中才会生长,去除乙酸钠对其余菌株生长影响不显著;③当柠檬酸氢二铵、硫酸镁、磷酸氢二钾和硫酸锰4种无机盐在共发酵培养基中分别去除时均会对某些菌株的生长造成抑制,所以4种无机盐在共发酵培养基中的添加十分必要;④复合益生菌的最佳吸附剂为玉米粉,最佳冻干保护剂为脱脂奶粉,最佳使用质量分数为16%.

In order to realize the co-fermentation culture of four aquaculture probiotic strains including Bacillus subtilis,Lacto-coccus garvieae,Pseudomonas stutzeri and Yeast,the single inorganic salt removal experiment and freeze-drying protective agent screening experiment were carried out.The results were as follows:①The specific components of the four-strain compound fermentation medium included glucose 20 g,peptone 10 g,beef extract powder 5 g,yeast powder 5 g,MgSO40.1 g,diammo-nium hydrogen citrate 2 g,K2HPO42 g,MnSO40.05 g,tween 801 mL and distilled water 1000 mL.②Bacillus subtilis can only grow in medium with sodium acetate removed,and the removal has no significant effect on the growth of the remaining strains.③When the four inorganic salts,i.e.diammonium hydrogen citrate,magnesium sulfate,dipotassium hydrogen phosphate and manganese sulfate were removed respectively in the co-fermentation medium,they would inhibit the growth of some strains,so the addition of the four inorganic salts in the co-fermentation medium was very necessary.④Through the comparative screening experiment of adsorbents and protective agents,it is determined that the best adsorbent for composite probiotics was corn flour,and the compound probiotic freeze-drying protective agent was skimmed milk powder,the best mass fraction of which was 16%.