从近百份土样中,首先筛选得到具有明显半纤维素水解活性透明圈的菌株564株,其中202株的木聚糖酶活力用96孔板筛选方法进行了验证.结果显示:基于96孔深孔板测定的酶活力与初筛测得的透明圈活力趋势一致.最终筛选得到一株高产木聚糖酶的菌株ECU2023,经核糖体rDNA内部转录间隔区的序列对比,鉴定为泡盛曲霉(Aspergillus awamori).研究获得了其最佳培养条件:pH 6.0,培养时间4d,C源为30～ 40 g/L玉米芯粉.经过(NH4)2SO4沉淀和Superdex G-75凝胶过滤层析后,其中主要木聚糖酶成分的最适反应pH为6.0,最适反应温度为50℃.%Hundreds of various soil samples were collected. Firstly,564 strains with halo-forming zones were isolated. Then, the xylanase activities of 202 strains were further verified by a 96-deep-well microplate screening assay. The activities from 96-deep-well microplate and halo-forming plate showed the same trend. The best strain ECU2023 with the highest xylanase production was identified as Aspergillus awamori by internal transcnbed spacer (ITS) sequencing. The culture conditions were optimized as follows:30 ~ 40 g/L corn cob powder, pH 6. 0, cultivation for 4 d. Furthermore, the main xylanase component was crudely was purified by ammonium sulfate precipitation and Superdex G-75 chromatograph. The xylanase activity was optimally performed at 50 ℃ and pH 6.0.
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