高产β-葡萄糖苷酶与单宁酶乳酸菌的筛选及其在红枣汁发酵中的应用

    Screening of high-yielding β-glucosidase and tannase lactic acid bacteria and their application in jujube juice fermenting

    • 摘要: 为了筛选出高产β-葡萄糖苷酶与单宁酶的乳酸菌菌株,使用p-NPG法从源自发酵食品的70株乳酸菌中初步筛选得到34株生长力旺盛、产β-葡萄糖苷酶能力强的乳酸菌。在此基础上,使用绕丹宁法复筛出2株高产单宁酶的菌株,分别命名为GD03、GD05,进一步采用浓度梯度法对两株乳酸菌在红枣汁中进行驯化培养。研究结果表明:驯化后的菌株GD03、GD05适应红枣汁环境,发酵后菌株胞内、胞外β-葡萄糖苷酶及单宁酶胞外酶活较发酵前显著提高(P<0.05);GD03、GD05在红枣汁中发酵后β-葡萄糖苷酶胞内酶活较发酵前均提高了7倍,β-葡萄糖苷酶胞外酶活均提高了22倍,单宁酶酶活分别提高了4倍和6倍;可溶性膳食纤维含量分别提高了1倍和0.5倍,单宁含量分别下降了50.69%和55.40%。该研究结果对筛选高产β-葡萄糖苷酶与单宁酶乳酸菌提供了新的思路,为高产酶乳酸菌应用于植物基发酵食品奠定了理论基础。

       

      Abstract: To screen out lactic acid bacteria strains with high β-glucosidase and tannase productivity, the p-NPG method was initially employed to select 34 robustly growing lactic acid bacteria strains with strong β-glucosidase production capabilities from 70 lactic acid bacteria strains sourced from fermented foods. Building upon this, the danthronine method was used for further screening, yielding two strains with high tannase productivity, designated as GD03 and GD05. These two strains were subsequently domesticated and cultured in jujube usinga concentration gradient method. The results indicated that the domesticated strains GD03 and GD05 adapted well to the jujube juice environment. Both the intracellular and extracellular β-glucosidase activities, as well as the extracellular tannase activities of these strains were significantly increased after fermentation compared with pre-fermentation levels (P < 0.05). Specifically, the intracellular β-glucosidase enzyme activity increased 7-fold, while their extracellular β-glucosidase enzyme activities both increased by 22-fold. The extracellular tannase enzyme activities increased by 4-fold and 6-fold for GD03 and GD05, respectively. Additionally, the soluble dietary fiber content increased by 1-fold and 0.5-fold, and the tannin content decreased by 50.69% and 55.40%, for GD03 and GD05, respectively. These findings provide new insights into screening for lactic acid bacteria with high-yielding β-glucosidase and tannase productivity and lay a theoretical foundation for the application of high-enzyme-yielding Lactobacillus in plant-based fermented foods.

       

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