Stereoselective Degradation Of Chiral Pesticide In Monascus Fermentation

The behavior of chiral pesticide enantiomers are often different in the environment and in vivo.In the study,we studied the stereoselective degradation of chiral pesticides myclobutanil and hexaconazole during the solid-state,submerged fermentation of Monascus and Monascus wine brewing process.Meanwhile,we studied the effects of chiral pesticides during the the solid-state and submerged fermentation of Monascus at the enantiomer levels.The stereoselective degradation of chiral pesticides was analysed with high performance liquid chromatography-tandem mass spectrometry during the solid-state,submerged fermentation of Monascus and Monascus wine brewing process.The results showed that the enantiomers of myclobutanil and hexaconazole were significantly degraded during the submerged fermentation of Monascus,and the degradation rate of(+)-myclobutanil was slightly higher than that of(-)-myclobutanil,the degradation rate of(+)-hexaconazole was also slightly higher than that of(-)-hexaconazole.However,the degradation rate of two enantiomers of myclobutanil and hexaconazole was the similar in the solid-state fermentation and Monascus wine brewing process,no stereoselective degradation was occured.The different concentrations(5 mg/L,0.5 mg/L and 0.05 mg/L)were used to detect the effects of chiral pesticide racemates and enantiomers on enzyme production of Monascus(glucoamylase,cellulose,protease),and typical metabolites(Monascus pigment,citrinin).The results showed that the racemates and enantiomers of myclobutanil and hexaconazole showed certainly differences in enzyme production and metabolism of Monascus.At 5 mg/L,0.5 mg/L of racemates and enantiomers of hexaconazole,enzyme production and metabolites had a significant change,(+)-hexoxazole was significantly more than that of(-)-hexaconazole,and 5 mg/L concentration was significantly greater.At 0.05 mg/L of racemates and enantiomers of hexaconazole,no significant difference was occured between enzyme production and metabolism of Monascus.However,there was also no significant difference between racemates and enantiomers at different concentrations of myclobutanil.In Monascus wine brewing process,the effects of quality parameters were analysed under the condition of myclobutanil and hexaconazole.The results showed that the alcohol content,total sugar and pigment contents in Monascus wine brewing process were inhibited in different degree,the total acid content was reversed,and were more strongly inhibited under the condition of hexaconazole.