Isolation and Identification of Xylitol Dehydrogenase Gene from Trichoderma reesei
瑞氏木霉木糖醇脱氢酶基因的分离与鉴定

A cDNA sub library from the fungus Trichoderma reesei grown on xylan was constructed in S.cerevisiae recombinant strain H475 harboring xylose reductase (XR)gene from Pichia stipitis .The sub library was screened for xylitol dehydrogenase (XDH) gene on SC selective medium in which xylose was used as a sole carbon source.The XDH gene,xdhl,was isolated from this sub pool and the length of xdhl is about 1.3kb.Southern,Northern and Western blot were carried out.The results indicated that xdhl has high affinity with T.reesei and the molecular weight of the xylitol dehydrogenase produced by S.cerevisiae recombinant strain HX1 is about 40 kDa.The strain HX1 harboring both xr from P.stipitis and xdhl from T.ressei was able to grown on xylose medium and converted more than 90% of the xylose into xylitol,ethanol and another by products.