Studies On DVS Starters Of Lactobacillus Rhamnosus GG

Lactobacillus rhamnosus GG(ATTCC53103)was discovered from healthy person. It's a probiotic strain that has attracted most attentions and the best documentated in this field. It can tolerate intestinal conditions and adhere both to intestinal mucus and to epithelial cells. The functional properties of LGG include balance the subjects' intestinal microflora, reduce the risk of diarrhoea, bind and eliminate toxins, lower the risk of dental caries and enhance the immunity. The fermentation productions of lactic acid which are currently commercially available mayor in lactobacillus acidophilus and Bulgaria bacilli, few of lactobacillus rhamnosus. In this study, efficient starter culture is hoped obtained through studies on direct-to-vat of lactobacillus rhamnosus, which provide the lactobacillus rhamnosus yogurt products with direct-to-vat cultures.The research on lactobacillus rhamnosus starter is studied from the following aspects, the main contents as follows:1. First, we begin with optimizing the external culture environment of the basic medium, including optimization in the initial pH, culture temperature, and incubation quantity. Ultimately, the optimum conditions are incubation quantity3%, pH6.5,30～35℃,72h.2. Make a understanding of the growth condition of lactobacillus rhamnosus, master its growth regularity, determine the culture medium of lactobacillus rhamnosus, and draw its growth curve according to OD values.3. The optimum buffer, KH2PO4, is screened through single-factor experiments, and it is beneficial to prolong the proliferation culture time.4. Optimize the medium components, and choose more suitable carbon sources, nitrogen sources, and growth factors for lactobacillus rhamnosus.5.Optimize the centrifugal conditions of lactobacillus rhamnosus culture medium, and the optimal centrifugal conditions,3000rpm,10min, is determined.