Qingdao Mental Health Center, Qingdao University, Qingdao 266034, China.
Marine Science and Engineering College, Qingdao Agricultural University, Qingdao 266109, China.
Mar Drugs. 2020 Oct 30;18(11):546. doi: 10.3390/md18110546.
Tannase plays a crucial role in many fields, such as the pharmaceutical industry, beverage processing, and brewing. Although many tannases derived from bacteria and fungi have been thoroughly studied, those with good pH stabilities are still less reported. In this work, a mangrove-derived yeast strain Q95, capable of efficiently degrading tannin, was screened to induce tannase, which exhibited an activity of up to 26.4 U/mL after 48 h cultivation in the presence of 15 g/L tannic acid. The tannase coding gene was cloned and expressed in . The activity of recombinant tannase (named TanRd) was as high as 27.3 U/mL. TanRd was purified by chromatography and analysed by SDS-PAGE, showing a molecular weight of 75.1 kDa. The specific activity of TanRd towards tannic acid was 676.4 U/mg. Its highest activity was obtained at 40 °C, with more than 70% of the activity observed at 25-60 °C. Furthermore, it possessed at least 60% of the activity in a broad pH range of 2.5-6.5. Notably, TanRd was excellently stable at a pH range from 3.0 to 8.0; over 65% of its maximum activity remained after incubation. Besides, the broad substrate specificity of TanRd to esters of gallic acid has attracted wide attention. In view of the above, tannase resources were developed from mangrove-derived yeasts for the first time in this study. This tannase can become a promising material in tannin biodegradation and gallic acid production.
单宁酶在制药工业、饮料加工和酿造等许多领域都发挥着关键作用。虽然已经对许多来源于细菌和真菌的单宁酶进行了深入研究，但具有良好 pH 稳定性的单宁酶仍然报道较少。本工作筛选了一株能有效降解单宁的红树林来源酵母菌株 Q95，在 15 g/L 单宁酸存在下培养 48 h 后，单宁酶的活力最高可达 26.4 U/mL。克隆并在 中表达了该单宁酶的编码基因 。重组单宁酶（命名为 TanRd）的活力高达 27.3 U/mL。通过色谱法纯化 TanRd，并通过 SDS-PAGE 进行分析，其分子量为 75.1 kDa。TanRd 对单宁酸的比活力为 676.4 U/mg。其最适反应温度为 40°C，在 25-60°C 下观察到的活性超过 70%。此外，它在 pH 2.5-6.5 的较宽范围内具有至少 60%的活性。值得注意的是，TanRd 在 pH 3.0-8.0 范围内具有极好的稳定性；孵育后仍保持其最大活性的 65%以上。此外，TanRd 对没食子酸酯的广泛底物特异性引起了广泛关注。鉴于此，本研究首次从红树林来源的酵母中开发了单宁酶资源。该单宁酶在单宁生物降解和没食子酸生产方面具有广阔的应用前景。
