Purification and Enzymatic Characters of Recombinant Oxidase Responsible for Zearalenone Biodegradation
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Abstract:
The recombinant Pichia pastoris strain GS115/pPIC9K-Oxa expressing oxidase Oxa derived from Acinetobacter sp.SM04 was studied, including purification of fermentation supernant, identification of secondary structure of recombinant Oxa, ZEN-degradating ability and enzymatic characteristics. After ethanol precipitation, anion-exchange chromatography and ultrafiltration, recombinant Oxa was puri?ed more than 20 folds and exhibited remarkable efficiency in ZEN removement by over 80% degradation rate. Its secondary structure is mainly composed of random coils and β-sheet, supplemented by less β-turn and α-helix. Oxa acted as a typical thermostable alkalase by which the ZEN degradation rate was maintained above 60% in pH 9.0-11.0 buffer from 50 to 70°C. In addition, the optimum temperature and pH were 60°C and 9.0, respectively. Some proper concentration of Cu2+, Fe2+ and Fe3+ individually in environment would accelerate degradation of Oxa. The results could be helpful to evaluate the molecular structure and mode of action of Oxa in future. It would make significant practical sense for the biodegradation of zearalanone.
