Abstract:

An optimized method for determining of ochratoxin A (OTA) in aqueous solution was proposed, and screening
of six strains isolated from vineyard soil for microbial OTA degradation was performed using the developed method. By
adding either methanol or ethanol, the recovery rate of OTA in aqueous solution was increased to more than 90%, and its
concentration could accurately determined at an addition ratio of 1:1 by volume. It was demonstrated that B-1 (bacterium)
and Y-2 (yeast) were able to degrade OTA. After incubation for two days, B-1 reduced 87% of OTA, and it was thoroughly
degraded another day later. Y-2 showed similar ability to degrade OTA, with a degradation rate of 84% after two-day
cultivation, and the concentration of residual OTA was stable in the following days. Moreover, LC-MS was used to detect
OTA byproducts. Finally, through sequence analysis of the 16S rDNA and 5.8S internal transcribed spacer (ITS) ribosomal
DNA (rDNA) regions, respectively, B-1 was identified as Brevundimonas vesicularis, while Y-2 as Yarrowia lipolytica.

Key words: ochratoxin A (OTA), recovery, degradation, microorganisms, screening, identification