| 摘要 |
A method of cloning of xylanase clones from an anaerobic rumen fungus including the steps of: (i) cultivation of an anaerobic rumen fungus; (ii) isolating total RNA from the culture in step (i); (iii) isolating poly A + mRNA from the total RNA referred to in step (ii); (iv) constructing a cDNA expression library; (v) ligating cDNA to a bacteriophage expression vector selected from .lambda.ZAP, .lambda.ZAPII or vectors of similar properties; (vi) screening of xylanase positive recombinant clones in a culture medium incorporating xylan by detection of xylan hydrolysis; and (vii) purifying xylanase positive recombinant clones. There is also provided xylanase positive recombinant clones produced by the above-mentioned method as well as xylanase positive recombinant clones having the following properties: (i) production of xylan clearing zones in a culture containing xylanase cDNA derived from N. patriciarum; (ii) having activity in hydrolysis of xylan but having no activity in relation to hydrolysis of CMC or crystalline cellulose. There is also provided various cDNA molecules which may be utilised in the above-mentioned method.
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