Detoxification of the Mycotoxin Citrinin by a Manganese Peroxidase from Moniliophthora roreri .

Citrinin (CIT) is a mycotoxin found in foods and feeds and most commonly discovered in red yeast rice, a food additive made from ordinary rice by fermentation with Monascus . Currently, no enzyme is known to be able to degrade CIT effectively. In this study, it was discovered that manganese peroxidase ( Mr MnP) from Moniliophthora roreri could degrade CIT. The degradation appeared to be fulfilled by a combination of direct and indirect actions of the Mr MnP with the CIT. Pure CIT, at a final concentration of 10 mg/L, was completely degraded by Mr MnP within 72 h. One degradation product was identified to be dihydrocitrinone. The toxicity of the CIT-degradation product decreased, as monitored by the increased survival rate of the Caco-2 cells incubated with Mr MnP-treated CIT. In addition, Mr MnP could degrade CIT (with a starting concentration of up to 4.6 mg/L) completely contaminated in red yeast rice. Mr MnP serves as an excellent candidate enzyme for CIT detoxification.