Screening Of Lovastatin-high-yielding Monascus Strain And Applying In Soy Sauce Waster Water

Since found that M.rubber could produce lovastatin, which ischolesterol synthesizing inhibitor, researchers both in china and abroadhad been making study of it. Now researchs of lovastatin focused onbiosynthetic pathway, optimization of fermentation and the high-yieldingstrain breeding. There were rarely researchs involved in the study of thesubstituted substrate in fermentation. The soy sauce wastewater could beused by microorganism because of abundant nitrogen source. Therefore,the production of lovastatin using soy sauce wastewater had a certainsocial and economic significance.In this study, LiCl mutation breading was conducted for increasingthe production of lovastatin. The fermentation condition，the processparameters by higher yield lovastation mutant were discussed. And theimpact factors of producing lovastation through sauce wastewater bydomesticated strain were discussed. The results were as follows:Using Monascus Purpureus HW as original strain, LiCl mutationbreading was conducted for increasing the production of lovastatin. Six ofhigh-lovastatin mutants were respectively obtained through determinationof lovastatin in the broth by HPLC. Among these mutants, the yield oflovastatin by HW3, HW5and HW6reach35.94,38.86and30.07mg/L,which were214%,239%and169%higher than that by the original strain,respectively. It was found that strain HW2showed stronger adaptionability, and higher yield of lovastatin in the soy sauce wastewater throughdomestication experiments.The detection method of lovastatin content was HLPC and thedetection process was complex, time-consuming and can not visuallyscreen high-yielding lovastation monascus strain. The production of redyeast rice pigment was often accompanied by the production of lovastatinat fermentation. Therefore, it was easy to screening the high-yieldlovastatin monascus strain by color value, because of the positivecorrelation between color value and the yield of lovastatin. Thecorrelation coefficient was exceeding0.91.By single factor and orthogonal experiments, the optimum conditionfermentation of the HW2was determined. The optimization fermentation of mutant HW2was as follow:180r/min,6%sucrose,4%soy flour,0.5%sodium acetate,28℃, and the higher yield of lovastation reached71.48mg/L, which were288%higher than that by the initial fermentationsubstrate(24.84mg/L).The conditions of cultivating monascus in soy sauce wastewater toproducing lovastatin had been studied. In order to feed strain and producemore lovastation adding carbon source was necessary and6%(massfraction) sucrose was best. The manner and time of soy sauce wastewaterstorage influenced lovastation yield. The soy sauce wastewater should bepreserved at4℃less than one and half month for higher yield oflovastation.