Effect Of Blue Light On The Production Of Ankaflavin And Monascin In Monascus And Purification Of The Two Pigments

As natural pigments,Monascus pigments have been regarded as one high-safety and edible pigments.Ankaflavin and monascin,the two yellow pigmtns of Monascus pigments,have been reported to prossess anti-cancer activity,which causing the extensive interest of researchers recently.In the present study,ankaflavin and monascin were identified in liquid fermentation product of monascus M9 by means of LC-MS.Then,during the process of liquid shake flask culture,the generation curves of biomass and pigment were studied with rice powder as culture medium.The results showed that biomass and pigment concentration of M9 were both stable from 6th to 9th day,and the mycelium during this time were used for the extraction of pigment.Furthermore,on the basis of Box-Behnken experimental design,the extraction condition of yellow pigments was optimized with the response surface method.The optimal extraction condition of yellow pigments is as follows:n-hexane as extraction solvent,liquid to solid ratio 90:1,ultrasonic power 100 w,extraction for three times,and each time for 15 min.The allocation proportion of monascin,rubropunetatin,akanavin,monascorubrin in the n-hexane/methanol/water system was investigated.The similar k value in upper and lower phase is found for monascin and rubropunetain,ankaflavin and monascorubrin.But the k value for monascin and akanavin varies a lot.Finally the optimal separate condition for monascin is n-hexane/methanol/water with the ratio of 10:5.5:4.5,while for akanavin is 10:7:3.AB-8 macroporous resin and silicone resin were used to separate yellow pigments,respectively.The eluent solvent for AB-8 and silicone are ethanol solution(>70%,v/v)and n-hexane/ethyl acetate(4:1,v/v),respectively.By comparing the separation results of AB-8 and silicone,a method of combining silicone and high speed counter-current chromatography to purify monascin and akanavin is established and in the separation result,the proportion of chromatographic peak area accounted for more than 99%.This study proved that under the blue light(90±5 lux),the amount of monascin and akanavin in mycelium of M9 could be increased during liquid fermetation,while the pigment exsited in mycelium was decreased.However,the increasing amount of pigment is higher than that decreased of the pigment.