Characterization of Enzyme Profiles of Lactobacillus casei Species by a Rapid API ZYM System

Abstract

Lactobacilli have gained much attention recently due to their strong peptidase and esterase activities, which are of great importance in the accelerated maturation and enzyme modification of cheese. Twenty strains of Lactobacillus casei (ssp. casei, ssp. rhamnosus, and ssp. pseudoplantarum) were compared for their enzyme profiles. Specificity and specific activity studies were carried out on 19 hydrolytic enzymes for each strain using the microenzyme API ZYM system. Typical Lactobacillus casei enzyme profile indicated the presence of weak proteinase and high peptidase and esterase-lipase activities. The API ZYM method has been modified to evaluate and compare closely related Lactobacillus casei strains and also to identify the location of their enzymes (extracellular, cytoplasmic, cell wall, and membrane bound). The peptidase and most of the esterases and carbohydrases were intracellular, but the phosphatases were mostly cell wall and membrane associated. The API ZYM method offers a simple and convenient way for quick assessment of the hydrolytic enzymes of starter strains for both the industrial and research purposes. © 1990, American Dairy Science Association. All rights reserved.