Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", São José do Rio Preto, São Paulo, Brazil.
Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Usp, São Paulo, Brazil.
J Biotechnol. 2019 Mar 20;294:73-80. doi: 10.1016/j.jbiotec.2019.02.001. Epub 2019 Feb 20.
β-glucosidases are glycoside hydrolases that-particularly those from filamentous fungi-have been extensively explored in cellulose fiber saccharification and wine quality improvement. However, these enzymes from yeast have been poorly studied. In this study, an ethanol-glucose tolerant β-glucosidase that is secreted by Pichia guilliermondii (current name Meyerozyma guilliermondii) was purified and characterized. This enzyme exhibited an estimated molecular mass of 97 kDa and the highest activity between pH 3.5-5.5 and 55 °C. The β-glucosidase was also tolerant to acetone, ethanol, isopropanol, and methanol up to 30% and glucose at 1 M. It was also stable up to 55 °C for 80 min, maintaining 70% of its initial activity and in a wide pH range (pH 3-10). The enzyme exhibited 90-100% of its initial activity for 72 h at 20, 25, and 30 °C in presence of 10% ethanol at pH 3.5, which is a similar condition to winemaking. Studies that identify new enzymes and describe their purification are required for oenology applications. The β-glucosidase described herein is a promising candidate for use in the preparation of wine. Additionally, its tolerance to glucose is an important biochemical property that adds value to this enzyme and enables it to be used during the final saccharification process.
β-葡萄糖苷酶是糖苷水解酶，尤其是那些来自丝状真菌的糖苷水解酶，已被广泛应用于纤维素纤维糖化和改善葡萄酒质量。然而，酵母来源的这些酶尚未得到充分研究。在本研究中，我们从毕赤酵母（现名为梅里埃酵母）中纯化和鉴定了一种耐乙醇-葡萄糖的β-葡萄糖苷酶。该酶估计分子量为 97kDa，最适 pH 为 3.5-5.5，最适温度为 55°C。该β-葡萄糖苷酶还能耐受 30%的丙酮、乙醇、异丙醇和甲醇以及 1M 的葡萄糖。它在 55°C 下稳定 80 分钟，保持初始活性的 70%，在宽 pH 范围内（pH 3-10）稳定。在 20、25 和 30°C 下，在 pH 3.5 下含有 10%乙醇的条件下，该酶在 72 小时内保持初始活性的 90-100%，这与酿酒条件相似。需要对新酶进行鉴定并描述其纯化方法，以满足酿造学的应用需求。本文描述的β-葡萄糖苷酶是一种很有前途的葡萄酒酿造用酶候选。此外，其对葡萄糖的耐受性是一种重要的生化特性，提高了该酶的价值，使其能够在最终糖化过程中使用。
