Effect Of Fermentation Conditions On Monascine And Citrinin Content Of Monascus

In this paper,the effect of different liquid fermentation conditions on monascine and citrinin production was studied and an optimum medium for high monascine production without citrinin was obtained.This provided a theoretical basis for producting yellow monascus pigment and functional colors products.The main conteunts are illustrated as following:HPLC-MS was used to separate and identify the two yellow pigment extracted from the fermented product of M9,the test results showed two pigments,retention time was 9.86 min and 14.57 min,their molecular weight is 358D and 386D,so they are monascine and ankaflavine.Regression analysis was conducted for three evaluation methods for pigment evaluation.There were significant ternary and binary linear regression model between them only in the predicted value range of 0?16713.13.So we determined the main evaluation method was HPLC and compared the total peak area of monascine for quantitative analysis.Through single factor test culture conditions were obtained,the optimum cultivating conditions were as follows:initial pH 5.5,temperature 30 ? fermentation time 5 d.Carbon source,nitrogen source,inorganic salt of fermentation medium were screened by the single factor experiment,determined the basic components of liquid fermentation culture medium.Through the Box-Benhnken experiment the optimal medium for producing monascine was got:rice powder 5%,MgSO4 0.1%,KH2PO4 0.17%,NH4NO3 1.94%,NaNO3 0.3%,MnSO40.02%.Monascine production was 40.7%higher than before.In this condition the maximum production of monascine was improved to 69.10 mg/50 mL.The effect of blue light on the production of monascine and citrinin was studied and concluded that the influence of a short time blue light irradiation was promoting as the leading factor for producting monascine and citrinin.The content of monascine increased 6%and citrinin increased 25%if given 15 min and 30 min blue light every day in eight days.But long time exposure(12 h continuous irradiation)was mainly degradation effect.The study compared the effect of blue light,darkness and natural light on the pigment alcohol solution stability of monascus and the result showed that monascus pigment stability of ethanol solution under different light conditions was:dark>blue>natural light,and negative correlation existed between light intensity and the stability of monascine.