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Alpha-glactosidase activity of lactobacilli
Applied Microbiology
|November 1, 1973
Summary
Lactobacillus species possess alpha-galactosidase enzymes that break down specific sugars. These enzymes are constitutive, soluble, and show optimal activity within a defined pH and temperature range.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Lactobacilli are common bacteria found in various environments.
- Alpha-galactosidases are enzymes that hydrolyze alpha-linked galactose residues in oligosaccharides.
- Understanding the enzymatic capabilities of Lactobacillus species is crucial for applications in food science and biotechnology.
Purpose of the Study:
- To investigate the presence and characteristics of alpha-galactosidase activity in cell-free extracts of several Lactobacillus species.
- To determine the substrate specificity and optimal conditions for these enzymes.
- To explore potential transgalactosylase activity in Lactobacillus cellobiosis.
Main Methods:
- Enzyme assays were performed on cell-free extracts of Lactobacillus fermenti, L. brevis, L. buchneri, L. cellobiosis, and L. salivarius subsp. salivarius.
- Substrate hydrolysis was measured using melibiose, raffinose, and stachyose.
- Enzyme activity was characterized by varying pH and temperature.
- Transgalactosylase activity was assessed by incubating Lactobacillus cellobiosis extract with melibiose.
Main Results:
- Alpha-galactosidase activity was detected in all tested Lactobacillus species, indicating the enzyme is constitutive and soluble.
- The enzymes efficiently hydrolyzed melibiose and other alpha(1 --> 6) linked galactose oligosaccharides.
- Optimal activity for alpha-galactosidases was observed between pH 5.2-5.9, with varying optimal temperatures for each species.
- Lactobacillus cellobiosis extract exhibited transgalactosylase activity, producing manninotriose from melibiose.
Conclusions:
- The studied Lactobacillus species possess functional alpha-galactosidases with specific substrate preferences.
- These enzymes are active under physiological conditions and could play a role in carbohydrate metabolism within the host or in food fermentation.
- The identification of transgalactosylase activity suggests potential for oligosaccharide synthesis by these bacteria.