State Key Laboratory of Food Science and Technology, The Laboratory of Baking and Fermentation Science, Cereals/Sourdough and Ingredient Functionality Research, School of Food Science and Technology, Jiangnan University, Wuxi, China.
School of Biotechnology, Jiangnan University, Wuxi, China.
J Food Sci. 2024 Mar;89(3):1403-1413. doi: 10.1111/1750-3841.16955. Epub 2024 Jan 28.
A β-1,3-1,4-glucanase gene (Auglu12A) from Aspergillus usamii was successfully expressed in Escherichia coli BL21(DE3). The recombinant enzyme, reAuglu12A was efficiently purified using the one-step nickel-nitrilotriacetic acid affinity chromatography. The specific activity of reAuglu12A was 694.8 U/mg, with an optimal temperature of 55°C and pH of 5.0. The reAuglu12A exhibited stability at temperatures up to 60°C and within the pH range of 4.0-5.5. The reAuglu12A hydrolytic activity was increased in the presence of metal ions, especially K and Na , whereas it exhibited a K and V of 8.35 mg/mL and 1254.02 µmol/min/mg, respectively, toward barley β-glucan at pH 5.0 and 55°C. The addition of reAuglu12A significantly increased the specific volume (p < 0.05) and reduced crumb firmness and chewiness (p < 0.05) of wheat-barley sourdough bread during a 7-day storage period compared to the control. Overall, the quality of wheat-barley sourdough bread was improved after incorporation of reAuglu12A (especially at 3000 U/300 g). These changes were attributed to the synergistic effect of acidification by sourdough and its metabolites which provided a conducive environment for the optimal action of reAuglu12A in the degradation of β-glucans of barley flour in sourdough. This stabilized the dough structure, thereby enhancing the quality, texture, and shelf life of the bread. These findings suggest that reAuglu12A holds promise as a candidate for β-glucanase application in the baking industry.
从土曲霉（Aspergillus usamii）中成功表达了一种β-1,3-1,4-葡聚糖酶基因（Auglu12A）到大肠杆菌 BL21（DE3）中。使用一步镍-亚氨基二乙酸亲和层析法高效纯化了重组酶 reAuglu12A。reAuglu12A 的比活为 694.8 U/mg，最适温度为 55°C，最适 pH 为 5.0。reAuglu12A 在高达 60°C 的温度和 4.0-5.5 的 pH 范围内稳定。reAuglu12A 的水解活性在存在金属离子时增加，特别是 K 和 Na，而在 pH 5.0 和 55°C 下，对大麦β-葡聚糖的 K 和 V 分别为 8.35 mg/mL 和 1254.02 μmol/min/mg。与对照相比，在 7 天的储存期内，添加 reAuglu12A 可显著增加小麦-大麦酸面团面包的比容（p<0.05），并降低面包屑的硬度和咀嚼性（p<0.05）。与对照相比，在 7 天的储存期内，添加 reAuglu12A 可显著增加小麦-大麦酸面团面包的比容（p<0.05），并降低面包屑的硬度和咀嚼性（p<0.05）。与对照相比，在 7 天的储存期内，添加 reAuglu12A 可显著增加小麦-大麦酸面团面包的比容（p<0.05），并降低面包屑的硬度和咀嚼性（p<0.05）。与对照相比，在 7 天的储存期内，添加 reAuglu12A 可显著增加小麦-大麦酸面团面包的比容（p<0.05），并降低面包屑的硬度和咀嚼性（p<0.05）。总体而言，与对照相比，添加 reAuglu12A（尤其是 3000 U/300 g）可改善小麦-大麦酸面团面包的质量。这些变化归因于酸面团及其代谢物的酸化协同作用，为 reAuglu12A 在酸面团中降解大麦面粉β-葡聚糖的最佳作用提供了有利的环境。这稳定了面团结构，从而提高了面包的质量、质地和保质期。这些发现表明，reAuglu12A 有望成为烘焙工业中β-葡聚糖酶应用的候选酶。
