Screening of commercial hydrolases for the degradation of ochratoxin A.

Ochratoxin A (OTA) is a nephrotoxic and carcinogenic mycotoxin. The toxin is a common contaminant of various foods and feeds and poses a serious threat to the health of both humans and animals. A number of commercial hydrolases were screened for the ability to degrade OTA to nontoxic compounds. A crude lipase from Aspergillus niger (Amano A) proved to substantially hydrolyze OTA to the nontoxic OTalpha and phenylalanine, as confirmed by HPLC with fluorescence detection. The enzyme was purified by anion exchange chromatography to homogeneity. Activity staining of the purified enzyme with alpha-naphthyl acetate/Fast Red revealed only one band exhibiting hydrolytic activity. The specific activity of the purified enzyme toward OTA was 2.32 units/mg.