Methods for freeze drying lactiplantibacillus plantarum BS25 (lp BS25)

Abstract

The present invention provides a method for freeze-drying Lactiplantibacillus plantarum BS25 (LPBS25) to produce a lyophilized probiotic powder with high cell viability and extended shelf life. The method involves suspending LPBS25 cells in a cryoprotectant solution comprising 2.184% sorbitol, 5.112% trehalose, and 1.036% inulin, followed by a multi-step freezing process at -18°C and -80°C, and vacuum desiccation for six hours. Response Surface Methodology (RSM) was employed to optimize the cryoprotectant combination, achieving a survival rate of 96.37% and viable counts of 2.06×1011 CFU / g. The lyophilized powder maintains viability above 1.0×109 CFU / g during storage at -18°C or 4°C for up to one month and demonstrates suitability for probiotic applications. The present invention further includes methods for assessing cell viability, calculating survival rates, and evaluating shelf life to ensure the efficacy and stability of the probiotic product.