Abstract

Lactobacilli are important organisms used in several lactic acid fermentations. Lactobacilli cultured in milk perform activities like breaking down of lactose to simple sugars, proteolysis, lipolysis and lactic acid production. Lactobacillusdepends on proteolytic system for degradation of protein – casein in milk from which they get their complex nutrient requirements for growth. This complex proteolytic system consists of proteinases, peptidases and amino and peptide carriers. Yogurt fermented milk having increased nutritive value, is more palatable, easily digestible and assimilable than milk. It has been observed that many people are sensitive to milk and cannot digest it easily. In developing nations this is an important cause for concern as such sensitive people suffers from protein-energy deficiency, more so if they are from the economically weaker section of the society. In this study an attempt has been made to understand the proteinase system from Lactobacillus plantarum NCIM 2083. The enzyme was found to be cell wall bound. It was active optimally at 30°C at pH 7.0. The peptides obtained after proteolysis were studied using SDS- PAGE, HPLC techniques and Liquid chromatography mass spectrometry (LCMS).

Key words: Proteinase, lactobacillus, yogurt, casein, peptides.