Optimizing the degradation of aflatoxin B in corn by Trametes versicolor and improving the nutritional composition of corn.

BACKGROUND

Corn, being an important grain, is prone to contamination by aflatoxin B (AFB ), and AFB -contaminated corn severely endangers the health of humans and livestock. Trametes versicolor, a fungus that can grow in corn, possesses the ability to directly degrade AFB through its laccase. This study aimed to optimize the fermentation conditions for T. versicolor to degrade AFB in corn and investigate the effect of T. versicolor fermentation on the nutritional composition of corn. AFB -contaminated corn was used as the culture substrate for T. versicolor. A combination of single-factor experiments and response surface methodology was employed to identify the optimal conditions of AFB degradation.

RESULTS

The optimal conditions of AFB degradation were as follows: 9 days of fermentation, a fermentation temperature of 26.7 °C, a moisture content of 70.5% and an inoculation amount of 4.9 mL (containing 51.99 mg of T. versicolor mycelia). With the optimal conditions, the degradation rate of AFB in corn could reach 93.01%, and the dry basis content of protein and dietary fiber in the fermented corn was significantly increased. More importantly, the lysine content in the fermented corn was also significantly increased.

CONCLUSION

This is the first report that direct fermentation of AFB -contaminated corn by T. versicolor not only efficiently degrades AFB but also improves the nutritional composition of corn. These findings suggest that the fermentation of corn by T. versicolor is a promising, environmentally friendly and efficient approach to degrade AFB and improve the nutritional value of corn. © 2023 Society of Chemical Industry.