Ochratoxin A(OTA) is a fungal toxin widely distribute in food.Reducing or eliminating OTA in food and its raw materials is of great significance in improving food quality and ensuring national food safety.Previously,the amide hydrolase AF-OTd (Alcaligenes faecalis OTA degrading enzyme),which can degrade OTA,was identified from Alcaligenes faecalis in the laboratory.In this study,the protein AF-OTd was highly expressed through gene recombination,and the enzymatic properties of the purified AF-OTd protein were analyzed.The results showed that the degradation rate of the purified AF-OTd enzyme for OTA was over 90%,and the degradation activity was affected by temperature,pH,alcohol and metal ions.The optimal temperature and pH of the enzyme were 50 ℃ and 7.5,respectively.Increase of alcohol content lead to a decrease of enzyme activity.When the alcohol content increased to 8%,the remaining enzyme activity was almost zero.1 mmol/L of metal ions Ca2+,CO₂+,Cu2+,Mg2+,Mn2+,Zn2+,K+ and EDTA have different degrees of inhibition on the enzyme.At the same time,it was also found in this study that trace amounts of CO₂+ and Zn2+ could significantly promote the activity of AF-OTd.