Production for High-vitality Starter Culture of Lactobacillus plantarum NDC 75017 by High Cell-density Cultivation and Low-temperature Vacuum Drying

With the predominance of producing gamma-aminobutyric acid (GABA) in milk fermentation as basis, the objective of this study was to investigate the production of high-vitality starter cultures by Lactobacillus plantarum NDC 75017. The strain, isolated from traditional yogurt in Inner Mongolia of China, can produce gamma-aminobutyric acid-enriched fermented milk and possesses beneficial properties. In this study, the strain was grown in optimized mMRS media in 3.7 L fully instrumented fermenter to produce biomass. Cells grown in the stationary phase were harvested and freeze dried. The viable cell count was up to 2.22 x 10(11) CFU g(-1) of freeze-dried product upon the addition of 8% w/v trehalose, 4% w/v maltodextrin, 4% w/v L-glutamate sodium salt, and 10% w/v skim milk as cryoprotectants. These freeze dried cells were stored at temperatures of 25 degrees C and 4 degrees C and periodically checked for viability and preparation of fermented milk,which showed a higher cell viability and stability after stored at 4 degrees C in 210 days. Based on our result, the high-viability starter cultures could be easily and economically produced.