Research of growth factors in high cell-density culture of Lactobacillus reuteri LT018

Lactobacillus reuteri LT018 which separated from the faeces of centenarians living in Bama is an excellent probiotic.In order to achieve its high cell-density growth,in this study,on the basis of TPY fermentation,a certain fermentation components of the LT018 was developed through single factor,which could be illustrated as follows:tryptone,yeast powder,malt sugar,citric acid,sodium citrate,tomato juice and L-cysteine. The Plackett-Burman experiment was used to find that tryptone,citric acid and L-cysteine had significant impact on probiotic's growth,then steepest ascent was designed to approach optimum area fast,and the response surface analysis was used to optimize the combination of significant factor,and the optimum conditions were tryptone of 12.13 g / L,citric acid of0.4 g / L,L-cysteine of 0.6 g / L. Under this condition,the culture conditions was determined as follows: 4% of inocula,37 ℃,initial p H6.7 and statically cultured. The result showed that the viable count of LT018 was 7.13 ×1010cfu / m L,which was 10.7 times that of the count before optimization.