The esterolytic and lipolytic activities of the Lactobacilli. II. Detection of the esterase system of Lactobacillus helveticus, Lactobacillus bulgaricus. Lactobacillus lactis and Lactobacillus acidophilus

In the present work we report the intraceIlular esterolytic activities of Lactobacillus helveticus, L. bulgaricus, L. lactis and.L. acidophilus using several nitrophenyl derivatives of fatty acids.AIl the tested lactobacilli show activities towards derivatives up to five carbons.P-nitrophenyl derivatives were hydrolysed significantly faster than the O-nitrophenyl derivatives.L. lactis and L. acidophilus strains can be distinguished from the strains of L. bulgaricus and L. helveticus by their higher esterase activities.After electrophoretic separation in 7 % acrylamide gels, zymograms showed three main bands distributed from RF 0.5 to RF 0.3 for L. helveticus.From L. bulgaricus, four bands were distinguished, three of them with electrophoretic mobilities similar to main bands in L. helveticus.Sorne of the L. acidophilus and L. lactis strains were distinguished by the presence of up to three addition al bands of lower electrophoretic mobility.On the other hand, the specifie activity of esterase increased gradually during the growth of L. helveticus.The trend was different for the esterase system of L. bulgaricus since activity was almostsimilar during the different stages of growth.Generally, the optimum temperature for esterase production by the thermophilic lactobaciIli was found to be 40-45° C. Little specifie activity was detected after cell growth either at 35 or 55° C.In conclusion, thermophilic lactobacilli possess a complex esterolytic system.It is specifie towards short chain fatty acids.Unfortunately, difIerences between strains are two little for use of these results as a tool for the taxonomy of Lactobacilli.However, this type of enzymatic activities could be used as an indicator for the detection and the control of strains in mixed lactic acid bacteria cultures.