Glycerol Fermentation Strain Breeding And Optimization Of Process Conditions

Glycerol is an important chemical raw materials, because of its high moisture absorption,high degree of exclusion, water-soluble high and low freezing point, non-toxic, sweet, microbialdecomposition and has three hydroxyl groups easily can be made into a number of derivatives andother characteristics, glycerol is widely used in alkyd resins and rubber, tobacco, defense, paint,paint, paper, textile, cosmetics, food, medicine and other industries in more than1700products. Asnatural law, synthetic production of the various limitations of glycerin, glycerol production has beenunable to meet demand, we must rely on a large number of imports, this shortage situation willpersist. Therefore, starch, glycerol production by microbial fermentation method has importantpractical significance to the fermentation of glycerol is also imperative.Orthogonal test to determine the liquefaction of starch in the mash preparation of optimumprocess parameters were: use of high-temperature α-amylase enzyme for the liquefaction, its enzymeaddition level0.035g/100g starch, pH5.5, liquefied temperature of90°C, liquefaction time was3.5h.The optimum starch reification process parameters were: β-amylase glucoamylase addition level0.3g/100g starch, pH4.5, starch reification temperature of58°C, starch reification time was2.5h.Under optimal conditions, this starch mash obtained reducing sugar content of22.6%.Screened from the environment has a strain of yeast fermentation of glycerol ability M0,mutagenesis by UV treatment, has been a high glycerol yeast M1. Construction, including26SrDNAD1/D2region sequence analysis and physiological and biochemical methods of identificationtechniques, the yeasts were identified by6S rDNA D1/D2region sequence analysis and phylogenetictree showed that strain M1and Candida C.parapsilosis NRRL Y-12969T100%similarity, it can beidentified as Candida M1. Physiological and biochemical tests, according to the characteristics ofyeast and identification manuals, test proved that Candida strains M1features consistent with the26S rDNA D1/D2region sequence analysis of the results match.M1strains for screening out of medium and fermentation conditions were optimized, firstdetermine the carbon, nitrogen, phosphorus, carbon source to determine glucose, urea nitrogen,phosphorus source is corn syrup. Second, determine the content of nutrients, namely glucoseconcentration180g/L, urea concentration of2g/L, corn steep liquor concentration of0.4mL/L.Finally, glycerol fermentation conditions were optimized, the results show that the optimalfermentation conditions for the inoculum was10%,42%of the amount of sodium sulfite added,fermentation ph7.4, fermentation temperature30°C, glycerol yield to13.25g/L.