Effect Of Culture Conditions On Moiwascus CG-6 Growth And Metabolism Of Monacolin K

Monacolin K is a product of Monascus secondary metabolism process,which can effectively reduce cholesterol by inhibiting HMG-CoA synthesis,and has a significant effect on cardiovascular and cerebrovascular diseases.Slow growth and long fermentation period of Monascus is a major problem facing in the current production.This article from the Monascus fulginosus spores and hyphae growth to morphological changes to the accumulation of biomass and Monacolin K were systematically studied.Study on the environment and nutrients on the germination and accumulation of Monascus fulginosus spores,discussesd the relationship between changes of Monascus fulginosus morphology and the accumulation of monacolin K.Citrinin was detected at the same time with high yield of Monacolin K,so as to ensure its safety to meet the actual production needs.Genes which are related to the growth and reproduction changes and Monacolin K synthesis were determined by fluorescence quantitative PCR.This study provides theoretical support for the study of growth and secondary metabolite synthesis.The main results are as follows:Study on the culture of Monascus CG-6.In four medium jimmy juice,malt juice,PDA,GPA on the growth,sporulation and secondary metabolite accumulation,found that jimmy juice and malt juice mediums were beneficial to the accumulation of sexual spores and biomass,but not conducive to the Monacolin K and yellow pigments.GPA medium was beneficial to the anisospore and hypha accumulation of Monascus CG-6.Although the growth rate of PDA medium was not as good as that of the first three kinds of culture medium,but the amount of the synthesis of Monacolin K was the highest.The nutrient rich medium promoted the accumulation of hyphae and spores,while the medium with relatively poor nutrition was beneficial to the synthesis of secondary metabolites.Study with effects of different carbon source on Monascus CG-6 synthesis of Monacolin K,found that glycerol was the most conducive to the synthesis of Monacolin K.The study found 8%concentration of glycerol was the most conducive to the synthesis of lactone and acid forms of Monacolin K,the acid form Monacolin K yield was 5957.5 g/g,total Monacolin K was 9474.4 g/g,and acid form Monacolin K is 63%of total Monacolin K.I also found that the amount of extracellular Monacolin K was more than 70%of the intracellular Monacolin K.SEM results showed that high concentrations of glycerol mycelial growth intensive,less spore yield,which was not conducive to cell respiration.Researched effects of different nitrogen sources on Monascus CG-6 synthesis of Monacolin K,found that sodium glutamate was the most conducive to the synthesis of Monacolin K,but with the increase of the sodium glutamate concentration is not conducive to the accumulation of biomass.Integrated biomass and accumulation of two forms Monacolin K,using yeast powder as nitrogen source,sodium glutamate as cofactor,selected 8%glycerol by orthogonal design,1.5%yeast powder,sodium glutamate 0.5%test Monacolin K reached 9876.3 g/g,the biomass also reached the highest level of 1.35 g/tablet.The optimized conditions of fermentation products were not detected with citrinin.By RT-PCR method,study found that glycerol can improve Monascus CG-6 mokA?mokC?mokD?mokE?mokF?mokG?mokH gene expression,especially mokE gene in early fermentation been highly expressed while in the late stage was 3.4 times more than the control group.The high concentration of glycerol inhibited the synthesis mechanism of Monacolin K,I found that high concentration of glycerol reduced by mokB?mokC?mokD?mokE?mokF?mokG?mokH expression,causing the decline of Monacolin K accumulation.Cloning genes which are related to sporulation veA?flbA?laeA?PKA,study the expression of them during the fermentation,we found that the expression level of PKA and veA genes related to sexual reproduction is not high,and the gene flbA related to conidia accumulation expression increased first and then decreased,indicating the conidia accumulation is earlier than Monacolin K accumulation;global regulatory factor LaeA expression was increased during the fermentation process.