Study On Fermentation And Extraction Process Of Erythritol

Erythritol is kind of polyol which widely exist in nature. It is a new type offunctional sweetener, with low energy, low heat, low hygroscopicity, and good toleranceet al.. It is very popular with the broad masses of the people, especially for peoplesuffered from diabetes and obesity, so it is widely used in food, dairy products,medicine, cosmetics and other industries.In this paper, Candida lipolytica CGMCC2.2088was used as starting strain, thentreated by ultraviolet and nitrosoguanidine, screened by selective plates with xylitol andiodoacetic acid, at last we attained a strain named UV6with high erythritol production.The content of erythritol fermented by UV6could run up to16.5%confirmed bygenetic stability test.The fermentation conditions and technology of UV6were optimized. The optimummedium were: glucose30%, yeast extract0.6%, phytic acid0.03%, MgSO4andKH2PO40.025%, the initial PH value is5.5-6.0. The optimum transplantingconditionswere: fermentation time20-22h, cells0.9-1.0billion/ml, inoculation amount12%. Theoptimum fermentation conditions were: dissolved oxygen20-30%, temperature forearly stage28oC, temperature for ending stage32oC.When the glucose concentrationdecreased to18%, the fermentation process needed feeding glucose with18-20%residual sugar, which accounted for40%of the total material. By this way,the contentof erythritol reached up to177.2g/L.The fermentation liquid was separated by nano filtration to remove large proteinand pigments, and then was treated by evaporation, crystallization and centrifugation toget erythritol crude. In this work, we optimized the nano filtration membrane, the nanofiltration membranewith400-500wt. intercepted was selected to study the extractionprocess. The erythritol crude yield came up to98.6%, which was improved by10.41%,and the cost of erythritol fell by1126.40yuan/t.