Recombinant expression and surface display of a zearalenone lactonohydrolase from Trichoderma aggressivum in Escherichia coli

Zearalenone (ZEN), one of the most dangerous mycotoxins, causes enormous economic losses in the food and feed industries. To solve the problem of ZEN pollution, ZEN detoxifying enzymes are in emergent need. In this study, a zearalenone lactonohydrolase from Trichoderma aggressivum, denoted as ZHD-P, was heterologously expressed and characterized. The intracellular ZHD-P from E. coli BL21(DE3) exhibited high activity for ZEN degradation (191.94 U/mg), with the optimal temperature and pH of 45 degrees C and 7.5-9.0, respectively. With excellent temperature stability, the intracellular ZHD-P retained 100% activity when it was incubated at 25-40 degrees C for 1 h. Furthermore, we firstly constructed an E. coli cell surface display system for ZHD-P. The surface-displayed ZHD-P exhibited high activity against ZEN and showed optimal activity at 40 degrees C and pH 9.0. With superior pH stability, the surface-displayed ZHD-P retained 80% activity when it was incubated at pH 5.0-11.0 for 12 h. Interestingly, the metal ions tolerance of the surface-displayed ZHD-P was better than the intracellular form. Additionally, the surface-displayed ZHD-P could be reused four times with the residual enzyme activity of more than 50%. The biotoxicity assessment using P. phosphoreum T3 indicated that ZEN could be degraded into hypotoxic products by the intracellular or surface-displayed ZHD-P. ZHD-P could be feasible for ZEN detoxification.

Automated summary

In this study, a zearalenone lactonohydrolase from Trichoderma aggressivum (ZHD-P) was successfully expressed and characterized, showing high activity for ZEN degradation. The surface-displayed ZHD-P exhibited better temperature and pH stability, as well as superior metal ions tolerance compared to the intracellular ZHD-P. Moreover, ZHD-P could effectively reduce the biotoxicity of ZEN through degradation into less toxic products.