Isolation, purification and functional characterization of glucansucrase from probiotic Lactobacillus plantarum DM5

Autor: Deeplina Das, Arun Goyal
Rok vydání: 2014
Předmět:
Zdroj: Annals of Microbiology. 64:1715-1724
ISSN: 1869-2044
1590-4261
Popis: The probiotic Lactobacillus plantarum DM5 isolated from fermented beverage Marcha of Sikkim was explored for its ability to produce extracellular glucansucrase during fermentation. The strain L. plantarum DM5 displayed glucansucrase activity of 2.71 U/ml (0.48 U/mg) at 27 °C under static condition. The medium compositions for glucansucrase production were optimized and it was found that K2HPO4 (2.5 %, w/v), yeast extract (2.5 %, w/v), Tween 80 (0.6 %, v/v), and sucrose (5 %, w/v) enhanced the activity by 20 %, 22 %, 68 % and 230 %, respectively. Glucansucrase was purified using polyethylene glycol 400 and 1500 fractionation followed by gel filtration that gave specific activity of 18.7 U/mg with 40-fold purification. Purified enzyme exhibited maximum activity at 30 °C and pH 5.4. Zymogram analysis of purified enzyme confirmed the presence of glucosyltransferase of approximately 148 kDa. The Vm and Km of purified glucansucrase for sucrose as substrate was 19.6 μmoles/mg/min and 4.5 mM. Divalent cations Mg2+, Ca2+ and Co2+ enhanced glucansucrase activity by 16 %, 18 % and 19 %, respectively, whereas Hg2+ and Mn2+ decreased the enzyme activity by 81 % and 79 %, respectively, when assayed in presence of sucrose. Among stabilizers, dextran T-40, PEG 6000, PEG 8000, glutaraldehyde, glycerol, Tween 80 and acetonitrile; Tween 80 provided maximum stabilization with half-life of 86 days at –20 °C. The overall biochemical characterization reveals a promising novel glucansucrase that can compensate for the increasing demand of glucan as viscosifier and stabilizer in food industry.
Databáze: OpenAIRE
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