Screening Of Monacolin K-high-yielding Monascus Strain By Mutation Treatments And Its Application

Monacolin K , which reduces blood fat well , is one of the secondary metabolites of Monascus.The small-scale solid fermentation conditions in the laboratory were studied. Spore suspension inoculated into solid medium directly in the 250mL triangular flask.Long shaped rice were thorougly cooked but not mushy after cleaned and soaked 18 hours in water , then added some supplementary material.The solid medium were inoculationed into 20% spore suspension,with a given mass of acetic acid added.It was fermented at 30℃and after 4 days the temperature was changed into 23℃until day 11.The red yeast rice was whole grain and red inside without clumping.The content of Monacolin K had reached to 0.374mg/g.The Monacolin K content was detected by HPLC,and the best extration solvent,extration methods and mobile phase were selected.The Monacolin K content and acid form proportion were not loss under this conditions,so it's precisely.The red yeast rice was dried under 40℃and grinded up.Weighed 5g power and solubled it into 3mL methanol.Then it was extracted 20 minutes by ultrasonic , bathed at 40℃water during the whole night . After centrifugal separation,the liquid supernatant could be detected by HPLC.Both the contents of acid form and lactone form could be measured at the same time,under 238nm with methanol and 0.1% phosphoric acid proportion at 72:28.The sample pretreatment was easy and convenient for numerous mutated strains'fermentation products.Moreover,this methods was accurate.The Monacolin K content of the original strain was 0.374mg/g,with acid form proportion 52%.It was mutated by ultraviolet and microwave respectively.The best mutation dose of ultraviolet was 40 seconds,while that of microwave(with heat effect) was 20 seconds.The high-yielding strain was screened after mutations,called Z4.Its Monacolin K content was 2.006 mg/g,which was more than five times of original strain's,with acid form proportion increasing into 69%.Then Z4 was mutated by microwave secondly.The ZW19 strain was choosed as high-yielding and genetic stability.And the Monacolin K content was 2.301 mg/g,which was more than six times of original strain's,with acid form proportion increasing into 82%.The Monacolin K in high-yielding strain ZW19 was extracted by 75% ethanol, after water bath,ethanol extraction and recover.The crude extract was put up into yellow wine at some proportion.It could achieve ideal effects in sterilization by heating 30 minutes at 60℃,and content could keep steadily.This production maintained the taste of yellow wine,with addition of lipid lowing fuction.The Monacolin K content of this production was about 11.389mg,which was a good lipid lowing production.