| Theα-arbutin is a kind of highly effective and safe skin whitening agents and its whitening effect is of 10 times more than theβ-arbutin has.Moreover, theα-arbutin is capable of restraining directly the tyrosinase activity but without restraining the human body cells.This essay explore study on Enhancement Ofα-Arbutin Production by Xanthomonas maltophilia BT-112, including adding surfactants antioxidants,inducers,macromolecule dope and so on.At the same time,it comes to conclusions(the capacity of reaction system is one liter).According to the study on adding surfactants,Tween80 was the best when compared with different kinds of surfactants at different concentrations and times of surfactant addition.Experimental results showed that the suitable conditions were as follows:adding 3 g·L-1Tween80 during the 12 hours from the start of fermentation,fed-batch in three times,1 g·L-1every time.Under the conditions mentioned above,the product yield could reach 96.2%against the hydroquinone added.Hydroquinone concentration reached 60 mmol·L-1 and yield of production increased by 27.6%.The fermentation period was 36 h,12 h less than the case without adding surfactant. Adding chemical antioxidants restrained microbial growth more or less, then the conversation efficiency decreased.Although the nature of biological antioxidants is comparing gentle,they don't directly eliminate the oxygen in reaction system.Therefore they can't avoid Hydroquinone oxidation and increase its concentration.The glycosyltransferase and polymerase are compositive enzyme in Xanthomonas.It can't increase the quality of enzyme by adding substrate analogs.It is the most optimistic composing:50 g·L-1sugar in primary culture. According to breaking up of the cell,it was found that the quality ofα-arbutin and Hydroquinone remaining in cell were nearly zero.It could explain that theα-arbutin transformed by Hydroquinone entering into cell nearly released out of cell. |
