新型β-葡萄糖苷酶BglD2异源表达及水解虎杖苷能力

Heterologous expression of a novel β-glucosidase BglD2 and its application in polydatin-hydrolyzing

摘要:

从海洋细菌Bacillus sp. D1中克隆、重组表达β-葡萄糖苷酶BglD2，研究其酶学性质，并对其水解虎杖苷制备白藜芦醇的能力进行分析。BglD2的最适催化温度和pH分别为45 ℃和6.5，在30 ℃和pH 6.5条件下的半衰期约为20 h。BglD2能够水解含β (1→3)、β (1→4)、β (1→6) 等键型的多种底物。BglD2具有良好的糖促活特性，100 mmol/L葡萄糖和150 mmol/L木糖分别将酶活力提升2.0倍和2.3倍。BglD2具有较好的乙醇促活及耐受特性，30 ℃时，10%乙醇使酶活力提升1.2倍，25%乙醇存在时其仍保留60%的酶活力。BglD2具有水解虎杖苷制备白藜芦醇的能力，35 ℃条件下反应2 h水解率为86%。具有乙醇耐受及抗产物抑制等特性的β-葡萄糖苷酶BglD2在酶法水解虎杖苷制备白藜芦醇方面有应用潜力。

Abstract:

A novel β-glucosidase BglD2 with glucose and ethanol tolerant properties was screened and cloned from the deep-sea bacterium Bacillus sp. D1. The application potential of BglD2 toward polydatin-hydrolyzing was also evaluated. BglD2 exhibited the maximal β-glucosidase activity at 45 °C and pH 6.5. BglD2 maintained approximately 50% of its origin activity after incubation at 30 °C and pH 6.5 for 20 h. BglD2 could hydrolyze a variety of substrates containing β (1→3), β (1→4), and β (1→6) bonds. The activity of β-glucosidase was enhanced to 2.0 fold and 2.3 fold by 100 mmol/L glucose and 150 mmol/L xylose, respectively. BglD2 possessed ethanol-stimulated and -tolerant properties. At 30 °C, the activity of BglD2 enhanced to 1.2 fold in the presence of 10% ethanol and even remained 60% in 25% ethanol. BglD2 could hydrolyze polydatin to produce resveratrol. At 35 °C, BglD2 hydrolyzed 86% polydatin after incubation for 2 h. Thus, BglD2 possessed glucose and ethanol tolerant properties and can be used as the potential candidate of catalyst for the production of resveratrol from polydatin.