Study On Ferment SAM Saccharomyces Cerevisiae And Separation Purification

S-adenosyl-L-methionine(SAM)is an important metabolic intermediate in organism which is involved in many biochemical reaction.There are vast market for SAM as nutrient and drug.Our main task is carries on screening to yeast,and its fermentation conditions to do research.The separation and purification of them were preliminary studied.SAM can be obtained by three ways:chemosynthesis,enzymatic conversion technique,as well as microbial fermentation,of which fermentation is the primary way of industrial production.In our experiment one was choosen from four strains to produce SAM high saccharomycetes Sake,its output is the 1.71g/L.By the space-mutation Yeast Sake,was picked out 500 yeasts,then through refilter we obtained one to produce the SAM high strain,No.552 of the yeast than the originally and its production output increase 11.16%.By the fermentation,fermentation conditions Sake552 strain of did conduct a preliminary exploration.It were studied and identified the best initial pH is 5.0,while SAM accumulation phase is 6.0 in shake flask;best fermentation temperature is 28℃;Best medium are 20%distilled potatoes, glucose 7%,yeast extract 1%,Urea 1.4%,L-Met 1%,KH₂PO₄ 0.4%,K₂HPO4₀.2%,MgSO₄·7H₂O 0.5%, CaCl₂·2H₂O 0.2%.The culture conditions of the Yeast Sake 552 in fermentor 5L were optimized, including the prescription of cultural medium,pH,dissolved oxygen,agitation speed,aeration,feeding strategy of complementarity-cultural medium in different stages.The SAM content of the Yeast Sake 552 reached 3g/L after fermentation for 4 days under the optimized conditions.We also has researched the separation and purification process of SAM and has established a preliminary technics.The procedure followed with that the cell suspension of pH2 to be frozen for 24h then to disrupt it and then purify it with weak acid cation exchange resin,to crystal and deposit with methanol,to centrifugal deposition to freeze-dry it finally we got the crude SAM.