Determination of viability and proteolytic activity of freeze dried Lactobacilli at various temperatures during storage

A laboratory experiment was undertaken with an objective to check the viability and proteolytic activity of freeze dried Lactobacillus at various temperatures during storage. The experiment was laid out in completely randomized design with fifteen treatments and three replications. The Lactobacilli were isolated from curd sample and tested with catalase test and gram staining test Lactobacilli dehydrated by placing at-20°C for 12 hrs and rehydrated by sterilized water. Lactobacilli incubated on MRS agar with 5% lyo-protectant such as Lactose, galactose, maltose and sucrose. The grown Lactobacilli colonies showed good response to sucrose 4°C and less response to maltose 40°C. The Lactobacilli incubated on milk agar could not digest casein protein indicating that Lactobacilli was not proteolytic in nature.