Biochemical characterization of a novel ochratoxin A-detoxifying amidohydrolase from Terribacillus saccharophilus JX-8 and its application in grape juice and wheat flour

Ochratoxin A (OTA) is a widespread mycotoxin contaminating cereals, grape products, coffee, and spices, threatening global food safety and human health. Efficient detoxification strategies are therefore urgently needed. Herein, an OTA-degrading bacterium, Terribacillus saccharophilus JX-8, was isolated from Chinese sauerkraut juice, which completely degraded 12.4 μM OTA within 12 h via amide bond hydrolysis to yield non-toxic ochratoxin α (OTα). A novel OTA amidohydrolase OtaH was identified, sharing only 33%–42% sequence identity with previously characterized homologs. OtaH exhibited high catalytic efficiency ( k cat / K m  = 4028.57 mM −1  min −1 ) and remarkable thermostability, retaining >50% activity after incubation at 65 °C for 1 h. Moreover, 5 μg/mL OtaH achieved 64.9% and 94.6% degradation of OTA in grape juice and wheat flour, respectively, within 2 h at 25 °C, reducing residual OTA to 1.76 μg/L and 0.54 μg/kg. Notably, enzymatic treatment did not significantly alter pH, soluble solids content, titratable acidity, polyphenol content, or nutritional composition. This study provides a promising enzymatic strategy for OTA detoxification in food processing.