Ochratoxin A is degraded byYarrowia lipolytica and generates non-toxic degradation products

Abstract

The mycotoxin ochratoxin A (OTA) is a common contaminant of various plant-derived foods and feeds. However, methods for complete decontamination remain to be established. Recently, biological approaches for mycotoxin removal using various species of yeast have been explored. In the present study, we investigated the efficacy of OTA degradation by the yeast Yarrowia lipolytica under various conditions, altering yeast concentration, temperature, pH, and concentration of OTA in order to determine the optimal requirements of this species. At a yeast concentration of 108 cells/ml, the degradation rate was higher than that observed at any other concentration and, after 24 h, the OTA concentration was reduced to almost half of the initial level introduced to the culture. Further, Y. lipolytica cultured at 28 °C showed the highest level of OTA degradation. Similarly, the culture performed optimally at a pH of 4. The initial concentration of OTA also affected the ability of the yeast to degrade OTA, with the level of degradation being the highest when the initial OTA concentration was 0.1 μg/ml. Moreover, we also tested the toxicity of the OTA biodegradation products using HepG2 cells to determine the physiological applicability of this yeast species in the food industry and observed that these products were notably less toxic than non-degraded OTA. Y. lipolytica effectively reduced natural decay incidence of grapes, and had no negative effect to the storage quality of grape fruits. Taken together, these data suggest that Y. lipolytica could be a viable OTA contamination prevention/treatment option and additional research concerning its commercial use is warranted.

Minimizing Ochratoxin A Contamination through the Use of Actinobacteria and Their Active Molecules

“…Further studies could be performed with isotopically labeled OTA in order to elucidate the fate of the degraded mycotoxin [54]. Additionally, residual toxicity assays could be performed on HepG2 cells [55], or by in vivo systems like nematodes or zebrafish [56,57] to ensure the detoxification capacity of the studied actinobacteria strains.…”

Strategies and Methodologies for Developing Microbial Detoxification Systems to Mitigate Mycotoxins

“…A number of studies have evaluated intrinsic factors, including carbon source [26,34], nitrogen source [26,34,88], vitamins [26], metals ions [12,34,46,89,90,91,92,93], enzyme inhibitors and promoters [52,89,90,91,92,93,94], initial concentration of mycotoxins [93,95], initial concentration of cells [53,95] and initial pH value [12,14,17,26,31,34,41,46,54,60,88,89,95,96], as well as extrinsic factors, including temperature [12,14,17,25,26,31,34,38,41,46,52,54,60,88,89,95,96], aeriation (shaking rate) [26], oxygen preference [14], as well as pre-incubation [26] and incubation time [34,97]. The experimental designs and optimized biotransformation conditions are summarized in Table 2.…”

Protein and transcript profiling analysis of the response of Yarrowia lipolytica Y‐2 in the degradation of ochratoxin A

“…Y. lipolytica Y‐2 was isolated from grapes by our research team (Yang et al, ) and routinely maintained at 4°C on nutrient yeast dextrose agar medium (0.8% nutrient broth, 0.5% yeast extract, 1% glucose and 2% agar) (Sangon Biotech, Shanghai, China).…”

“…Yarrowia lipolytica Y‐2 which was isolated by our research team has the ability to degrade OTA. When Y. lipolytica Y‐2 was cultured with 100 ng/mL of OTA for 48 hr, the degradation rate was 95.7% (Yang, Wang, Zhang, Li, & Zhang, ). To the best of our knowledge, there is little information about the molecular mechanisms involved in the responses of antagonistic yeast to OTA degradation so far.…”