[目的]从自然界中筛选出具有木聚糖酶活力的菌株,为今后降解农作物秸秆提供材料.[方法]以木聚糖为唯一碳源,从土壤中筛选能够降解木聚糖的菌株,并对其进行鉴定和发酵条件优化.[结果]从土壤中筛选出一株能够降解木聚糖的菌株,综合菌落、菌体形态特征和18S rRNA序列分析,初步鉴定该菌株为土曲霉(Asperergillus terreus thom.)GY-1.单因素试验研究表明,菌株GY-1最佳碳源为蔗糖,Mg2+能提高其木聚糖酶活力,最佳氮源为硝酸铵,最适温度为30℃,最适pH为6.0,该菌在培养52 h时木聚糖酶活力最高,为880.11 U/ml.L16(45)正交试验结果表明,GY-1的接种量以及培养基中蔗糖、Mg2+和硝酸铵的添加量对其木聚糖酶活力均有显著影响,GY-1菌株的最优发酵条件为:50 ml基础发酵培养基中,接种量2％,蔗糖1g,硝酸铵0.03 g,Mg2+0.004 mol.[结论]该研究首次报道了土曲霉具有木聚糖酶活力,为研究土曲霉降解木聚糖提供了一定的试验依据.%[Objective] To screen some xylan-degrading strains from nature and also provide material for degrading straw. [ Method ] The xylan was used as sole carbon source to screen some strain capable of degrading xylan cellulolytic from the soil, the strain was then identified, and its fermentation conditions were optimized. [ Result ] A xylan-degrading strain was screened out from the soil. According its colony, morphological characteristics and the 18S rRNA sequence analysis,the strain was identified to be Aspergillus terreus,GY-1. The single factor experiments showed that the best carbon source was sucrose, Mg2 + could improve xylanase activity,the best nitrogen source was ammonium nitrate,the most suitable temperature was 30℃ ,the most suitable pH was 6.0,xylanase activity of GY-1 was the highest for 880.11 U/ml in 52 h. And L16(4S) orthogonal test showed that the quantity of GY-1' s inoculation, sucrose, Mg2 + and ammonium nitrate dosage had a significant effect on xylanase activity , the optimal conditions were 50 ml fermentation medium,2% inoculation quantity,1g sucrose,0. 03g ammonium nitrate,and 0.004 mol Mg2+. [Conclusion] The experiment reports that Aspergillus terreus has xylanase activity for the first time and provides a test basis for Aspergillus terreus degrading xylan.
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