Lactose hydrolyzing enzymes in Lactobacillus acidophilus strains
1985; Elsevier BV; Volume: 2; Issue: 1 Linguagem: Inglês
10.1016/0740-0020(85)90020-6
ISSN1095-9998
Autores Tópico(s)Enzyme Production and Characterization
ResumoFive Lactobacillus acidophilus strains were examined for lactose hydrolyzing enzymes under several growth conditions. All have both β-galactosidase (β-gal) and phospho-β-galactosidase (P-β-gal) activities. Strains W, ATCC 4356 and NCDO 1748 had different amounts of β-gal activity, but all had 100-fold or more higher than P-β-gal activity. In contrast, in strains ATCC 4962 and ATCC 19992, activities of both enzymes were similar. The β-gal synthesis in strains W, 4356 and 1748 was induced by lactose and galactose, while in strains 4962 and 19992 it appeared not to be inducible. At 45°C in the presence of lactose synthesis of only β-gal occurred in strains 4356, 1748 and W. These differences in lactose hydrolyzing enzymes between the strains could be used, along with other characteristics, for taxonomic differentiation between L. acidophilus strains. Studies with L. acidophilus W indicated that cells have maximum β-gal activity at their early stationary phase of growth and when grown in the presence of an inducer and in the absence of oxgall. Selection of strains, type of carbohydrate in growth medium, growth temperature, culture age, and the absence of oxgall during cell growth should be considered in producing L. acidophilus cultures containing high β-gal activity for use as a dietary adjunct by lactose-intolerant individuals and in the manufacture of acidophilus-fermented dairy products.
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