Study On Fermentation Technology Of Lactobacillus Buchneri IMAU80233

Twenty Lactobacillus buchneri strains were isolated from naturally fermented dairy products,and were used for screening of strains with acid and bile salt tolerance in this paper.The fermentation technology of L.buchneri IMAU80233 strain with excellent acid and bile salt tolerance was optimized.The results were as follows:(1)The results of acid and bile salt tolerance screening test showed that the survival rate of L.buchneri IMAU80233 in simulated artificial gastric intestinal fluid was 53.21%,and the growth delay in MRS medium containing bovine bile salt was 0.24 h.(2)On the basis of MRS medium,the maximum specific growth rate was used as the main index,and the components of L.buchneri IMAU80233 growth and multiplication medium were optimized by single factor test and response surface optimization test.The static medium was determined as follows:fructose 50.78 g/L,soybean peptone 23.90 g/L,yeast powder 11.90 g/L,citric acid 1.59 g/L,sodium citrate 20.06 g/L,MnSO4·5H2O 0.09 g/L,MgSO4·7H2O 0.60 g/L,Tween-80 1.00 g/L,arginine 0.50 g/L.The optimum static culture conditions of L.buchneri IMAU80233 were determined by single factor test on the optimized static medium:culture temperature 37?,initial pH 6.5 and inoculation volume 7%.After optimization,the maximum specific growth rate of L.blchneri IMAU80233 was 0.43 h-1,and the number of viable bacteria could reach 1.13 ×109 CFU/mL,which was 5.4 times higher than that in the MRS after 20 h culture.(3)A small-scale experiment was carried out in 5L×3 fermentor.The fructose content in the fermentation medium was 80.00 g/L.The optimum fermentation conditions were determined as follows:the neutralizer 25%of ammonia,constant pH 5.9,and keeping nitrogen pressure to the end of fermentation.After optimization,the number of viable bacteria in fermentation broth reached 3.81 × 109 CFU/mL,which was 18.3 times higher than that in MRS medium.Through optimizing the fermentation technology of L.buchneri IMAU80233,the preparation technology of L.buchneri IMAU80233 with low cost and high viable count was obtained.These data can provide theoretical guidance for the development of L.buchneri IMAU80233 microecological agents.