The Improved Expression and Stability of Zearalenone Lactonohydrolase from Escherichia coli BL21 (DE3)
Xiang Fu, Marc Xu, T. Li, Yong Li, Huiming Zhang, Chao Zhang
Abstract
Abstract Zearalenone (ZEN) is an estrogenic mycotoxin produced by Fusarium fungi which is commonly found in cereal crops. Because of its estrogen toxicity, ZEN can cause reproductive disorders and reduce immune function in human and animals. The zearalenone lactonohydrolase (ZHD 101) derived from Clonostachys rosea IFO 7063 can efficiently hydrolyze and detoxify ZEN. However, application of ZHD101 was always limited because of its instability and poor solubility. In this study, a codon-optimized DNA fragment for a recombinant dissolved ZHD101 (rdZHD) was designed and synthesized, and soluble rdZHD protein was successfully expressed and purified using Escherichia coli BL21 (DE3) expression system. HPLC results showed that 100 μg/mL ZEN could be thoroughly degraded by rdZHD within 6 h, and the ZEN degradation activity of rdZHD was calculated as 1150 U/mg. Furthermore, the purified rdZHD was immobilized with cross-linked poly(γ-glutamic acid)/gelatin hydrogel (CPE), and the activity and stability of immobilized rdZHD (CPE-rdZHD) was evaluated. The CPE-rdZHD showed better pH stability and thermostability than free rdZHD. The research could provide an effectively biological detoxification technology for ZEN degradation in agriculture and grain processing industry.