Fermentation And Transcriptome Analysis Of Kluyveromyces Marxianus Of Acetic Acid Tolerance

The microbial strains for the efficient conversion of cellulosic biomass to produce fuel ethanol are the research hotspots for cellulosic ethanol.Kluyveromyces marxianus has high growth rate and high temperature resistance and can use xylose to produce ethanol,which has a great advantage in the fermentation of lignocellulose ethanol.Our laboratory used Kluyveromyces marxianus 1727 as the starting strain to obtain new strain K.marxianus 1727-5 through strain domestication.Its xylose fermentation capacity and acetic acid resistance have significantly improved compared with the starting yeast.Combined with the fermentation experiments of glucose,xylose,and acetic acid for K.marxianus 1727 and K.marxianus 1727-5,the transcriptome under xylose and acetic acid was analysised.And the reasons for the increased xylose fermentation capacity and acetic acid resistance of the new strain were studied and analyzed.The main results were as follows:(1)The glucose fermentation performance of K.marxianus 1727-5 was similar to that of S.cerevisiae 4126,6525 used in ethanol industry,and the xylose fermentation capability was better.(2)1727-5 for inhibitor tolerance ability was much better than that of domesticated strains 1727,and had the ability to utilize acetic acid,which effectively alleviated the impact of acetic acid to the fermentation strain.(3)The transcriptome analysis found that compared with the starting strain,K.marxianus 1727-5 had differentially expressed genes,including Hsp26,Rim101,TR1,Zrt2 and ADH4 a.The expression differences of the four gene may be associated with resistance of acetic acid and acetic acid using.(4)In order to verified the gene's function,through genetic engineering methods,the expression vector of Zrt2 and ADH4 a in yeast were constructed.