The Screening And Identify Of Strains In Ability Of Ethanol Fermentation Using Xylose

Ethanol fermentation of xylose has been seen as a key factor in the biotransformation of plant. It is necessary for us to fiber raw materials for ethanol production, selection of high quality, high yield of xylose fermentation strains.The research has collected the soil of test plots of Hunan Academy of Agricultural University and the zoo panda droppings as the main raw material,Purification through a solid medium xylose as sole carbon source by a wild strain, results are as follows:1、We isolated16strains from a wild and which can be grown on xylose, After initial screening TTC identifcation medium we get selected strains with strong ability to ferment xylose to ethanol respectively marked M1、M2、M3、M4. In each of its temperature in28℃. fermentation time set as2d, shaking speed set in120rpm/min. inoculation of2%,2%xylose concentration of rescreening fermentation conditions,, the measured M3,M4, respectively, ethanol production reached of2.47g/L and1.82g/L is desirable target strains.2、Because of the fermentation process conditions have a greater impact on ethanol production and yield, so we designed the fermentation temperature, PH, substrate concentration, fermentation time single factor experiments and their four factors and L9(34) of orthogonal test,Orthogonal then optimize its fermentation of xylose to ethanol fermentation process conditions. The results show’that:in the xylose concentration30g/L, fermentation time was72h. initial pH5. the fermentation temperature is28℃under the conditions of M3ethanol yield reached25.3%under the original conditions of ethanol yield ratio improved by10.0%.3、By morphological and biochemical analysis to identify homologous genes, we、 identified M3as Candida.4、Regarding ethanol tolerance as the initial substance initial xylose fermentation medium were prepared at a concentration of1%by volume of ethanol to10%gradient in1%on xylose fermentation which under the conditions of fermentation in temperature of28℃,(100mL of ethanol was added to the culture medium lOmL) fermentation time2d. shaking speed of120rpm, vaccination an amount of2%, the ethanol resistance measured M3maximum capacity was32g/L; initial xylose tolerance initial substances were prepared in ethanol concentration of1%-10%gradient in1%xylose fermentation medium, under the conditions of fermentation in temperature of28℃, fermentation time2d, shaking speed of120rpm,2%inoculum, The measured resistance xylose M3capacity up to50g/L; to M3as fermentation agents at a temperature28℃. fermentation time2d, shaking speed of120rpm, inoculum size of2%, total sugar concentration of2%unchanged. The following1:1,1:2,1:3,3:1.2:1glucose and xylose fermentation conditions was mixed. The results showed that:the highest ethanol yield a single fermentation of glucose, glucose was added from the effects of glucose:We picked in Mi. M2, M3, M4between two mixed in1:1inoculation, at a temperature of28℃, fermentation time as2d. shaking speed120rpm. the total amount of inoculation fermentation conditions under2%that measured at any two xylose fermentation ethanol production levels which lower than any strain between the two, showed no synergistic effect.