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Isolation and basic characterization of a β‐glucosidase from a strain of Lactobacillus brevis isolated from a malolactic starter culture
Author(s) -
Michlmayr H.,
Schümann C.,
Barreira Braz da Silva N.M.,
Kulbe K.D.,
Del Hierro A.M.
Publication year - 2010
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2009.04461.x
Subject(s) - lactobacillus brevis , malolactic fermentation , lactobacillus plantarum , homotetramer , chemistry , oenococcus oeni , biochemistry , lactobacillaceae , fructose , fermentation , lactic acid , biology , food science , lactobacillus , bacteria , genetics , protein subunit , gene
Aims: To study glycosidase activities of a Lactobacillus brevis strain and to isolate an intracellular β‐glucosidase from this strain. Methods and Results: Lactic acid bacteria (LAB) isolated from a commercially available starter culture preparation for malolactic fermentation were tested for β‐glycosidase activities. A strain of Lact. brevis showing high intracellular β‐ d ‐glucosidase, β‐ d ‐xylosidase and α‐ l ‐arabinosidase activities was selected for purification and characterization of its β‐glucosidase. The pure glucosidase from Lact. brevis has also side activities of xylosidase, arabinosidase and cellobiosidase. It is a homotetramer of 330 kDa and has an isoelectric point at pH 3·5. The K m for p ‐nitrophenyl‐β‐ d ‐glucopyranoside and p ‐nitrophenyl‐β‐ d ‐xylopyranoside is 0·22 and 1·14 mmol l −1 , respectively. The β‐glucosidase activity was strongly inhibited by gluconic acid δ‐lactone, partially by glucose and gluconate, but not by fructose. Ethanol and methanol were found to increase the activity up to twofold. The free enzyme was stable at pH 7·0 ( t 1/2 = 50 day) but not at pH 4·0 ( t 1/2 = 4 days). Conclusions: The β‐glucosidase from Lact. brevis is widely different to that characterized from Lactobacillus casei (Coulon et al. 1998) and Lactobacillus plantarum (Sestelo et al. 2004). The high tolerance to fructose and ethanol, the low inhibitory effect of glucose on the enzyme activity and the good long‐term stability could be of great interest for the release of aroma compounds during winemaking. Significance and Impact of the study: Although the release of aroma compounds by LAB has been demonstrated by several authors, little information exists on the responsible enzymes. This study contains the first characterization of an intracellular β‐glucosidase isolated from a wine‐related strain of Lact. brevis .