灰盖鬼伞中过表达的碱性真菌漆酶在高盐染料废水中的应用潜力

An alkaline fungal laccase overexpressed in Coprinopsis cinerea shows application potential in treating high-salt dye wastewater

摘要:

【目的】 本研究利用双孢菇(Agaricus bisporus) gpdII启动子，实现了碱性真菌漆酶PIE5 (CcPIE5)在灰盖鬼伞(Coprinopsis cinerea) FA2222中的同源过表达。【方法】 在mKjalke液体培养基中37 ℃培养7 d，漆酶活力达到(24.2±1.1) U/mL。纯化的CcPIE5在pH 8.0和60 ℃下表现出最佳催化活性。【结果】 与已经研究报道的真菌漆酶不同，CcPIE5能耐受高浓度NaCl，当NaCl浓度从0升至1.5 mol/L时，CcPIE5的k_cat和K_m均呈下降趋势，表示CcPIE5在纺织印染废水脱色中有潜在应用价值。进一步在染料废水脱色应用中，以丁香酸作为介体，CcPIE5在pH 8.5和60 ℃条件下可高效降解(92.9±2.3)%的靛蓝胭脂红。通过LC-MS分析确认，Isatin 5-sulfonic acid (ISA)是靛蓝胭脂红降解的主要副产物。【结论】 CcPIE5在高温、碱性和含盐条件下高效脱色染料，是处理环境和工业特定应用的理想选择。

Abstract:

[Objective] To homologously overexpress an alkaline fungal laccase PIE5 (CcPIE5) in Coprinopsis cinerea FA2222 under the control of the Agaricus bisporus gpdII promoter. [Methods] The laccase activity reached (24.2±1.1) U/mL in the supernatant after 7 days of cultivation at 37 ℃ in the mKjalke medium. The purified CcPIE5 showcased the best performance at pH 8.0 and 60 ℃. [Results] Unlike other characterized fungal laccases, CcPIE5 was tolerant to high concentrations of NaCl. Particularly, both k_catand K_m decreased when the concentration of NaCl was increased from 0 to 1.5 mol/L, which indicated that CcPIE5 demonstrated application potential in the dye decoloring of texile finishing. In dye decolorization, CcPIE5 efficiently degraded (92.9±2.3)% indigo carmine at pH 8.5 and 60 ℃, with syringic acid as the mediator. Isatin 5-sulfonic acid (ISA) was identified by LC-MS as the primary byproduct of indigo carmine degradation. [Conclusion] CcPIE5 is best-suited in decolorizing dyes under high temperatures and alkaline and salty conditions. It serves as a good candidate for specific applications in the environment and industry.