可降解磺胺嘧啶的重组细菌漆酶诱导表达和酶学性质研究

Induced expression and enzymatic properties of recombinant bacterial laccase degrading sulfadiazine

中文关键词:  细菌漆酶  磺胺嘧啶  抗生素降解  异源表达  酶学性质  蛋白浓度

英文关键词:bacterial laccase  sulfadiazine  antibiotic degradation  heterologous expression  enzymatic properties  protein concentration

中文摘要:

      目的 探究重组细菌漆酶诱导表达水平及酶学特性, 提高细菌漆酶对磺胺嘧啶抗生素的降解效率。方法 本研究通过单因素实验探讨了诱导温度、诱导时间以及异丙基-β-D-硫代半乳糖苷(isopropyl β-D-thiogalactopyranoside, IPTG)浓度对酶表达量的影响。并通过pH和温度两方面对重组细菌漆酶的酶学性质进行探究。结果 24 h重组细菌漆酶对磺胺嘧啶的降解率达50%。重组细菌漆酶在大肠杆菌BL21 (DE3)中的最适表达条件为: 诱导温度16 ℃, 诱导时间16 h, IPTG浓度0.2 mmol/L。最适pH为3, 在pH为7时, 稳定性最好, 6 h酶活达到150%; 最适温度为80 ℃, 在温度为70 ℃时热稳定性最好, 1 h提高到120%, 半衰期约为6 h。结论 本研究为细菌漆酶在磺胺嘧啶抗生素降解中的应用提供了实验基础, 并为未来研究其在工业中的潜在应用奠定了理论依据。

英文摘要:

      Objective To investigate the induced expression level and enzymatic properties of recombinant bacterial laccase and to improve the degradation efficiency of sulfadiazine antibiotics by bacterial laccase. Methods In this study, the effects of induction temperature, induction time, and concentration of isopropyl β-D-thiogalactopyranoside (IPTG) on enzyme expression were investigated by one-way experiments. The enzymatic properties of recombinant bacterial laccase were also investigated by both pH and temperature. Results The degradation of sulfadiazine by recombinant bacterial laccase at 24 h was 50%. The optimal conditions for the expression of recombinant bacterial laccase in Escherichia coli BL21 (DE3) were as follows: Induction temperature of 16 ℃, induction time of 16 h, and IPTG concentration of 0.2 mmol/L. The optimal pH was 3, and the stability was best at pH 7, with the enzyme activity reaching 150% in 6 h. The optimal temperature was 80 ℃, and the thermal stability was best at 70 ℃, with the enzyme activity increasing to 120% in 1 h. The half-life was about 6 h. Conclusion This study provides an experimental basis for the application of bacterial laccase in the degradation of sulfadiazine antibiotics and lays down a theoretical basis for the future study of its potential application in the industry.