Proteolytic enzymes of lactic acid bacteria

Abstract

Abstract The proteolytic system of lactic acid bacteria is very important for the production of fermented milk products. Especially during the ripening of cheese, the proteolytic degradation of casein is an important event, since low molecular peptides and amino acids play a key role in formation of cheese flavor. In contrast to lactococci, which are widely used as cheese starter, not much is known about the proteolytic system of other lactic acid bacteria. Recently, 169 Lactobacillus strains of 12 species have been investigated for their proteolytic enzyme profile and as a result 5 highly proteolytic Lactobacillus strains were selected [1]. In a further study, the proteolytic enzymes of the selected Lactobacillus strains were compared with those of lactococci in Western blotting experiments by using antibodies raised against the purified proteolytic enzymes from Lc. lactis. In addition, the electrophoretic differences of the enzymes have been investigated by using specific zymogram staining method [2]. The results indicate that most of the proteolytic enzymes in lactobacilli are immunologically and electrophoretically different from those in lactococci.