高产木聚糖酶的紫色红曲霉菌株筛选及酶学性质研究

目的]筛选紫色红曲霉木聚糖酶,并研究其酶学性质。方法]采用平板筛选和固体培养方法获得了产木聚糖酶较高的紫红曲霉（Monascus pupureus）533。采用50%~70%硫酸铵盐析、Sephadex G-25凝胶层析、DEAE Sepharose fast flow阴离子交换层析和SephacrylS-200凝胶层析进行纯化。最后,研究温度、pH、金属离子和化学物质对酶活性的影响。结果]经分离纯化后得到相对分子质量约为46.0 kD的木聚糖酶。木聚糖酶最适反应温度为47℃;最适反应pH为5.5,pH稳定范围为4.5~5.5;Ca2＋、Fe2＋、Na＋和Tween 80对酶活力有激活作用;Mn2＋、Tris、EDTA、尿素和SDS对酶活力有抑制作用;Cu2＋和K＋对酶活力影响不大。结论]该研究筛选到1株高产木聚糖酶的紫色红曲菌株,扩大了产木聚糖酶的菌株范围。

Selection of High Xylanase Yielding Monascus pupureus Bacterium Strain and Its Properties of Enzyme

Objective] The research aimed to screen the xylanase from Monascus pupureus bacterium strain,and studied its properties of enzyme.Method] Monascus pupureus 533 was isolated from Monascus as the xylanase producer by the solid state culture.The xylanase was purified by 50%-70% ammonium sulfate precipitation,Sephadex G-25,DEAE-Sepharose fast flow column chromatographies and Sephacryl S-200.Finally,the effects of reaction temperature,pH,metal ions and chemical matters on the enzyme activity were studied.Result] The molecular weight of xylanase was 46.0 kD by separation and purification.The optimal temperature and pH for xylanase activity were 47 ℃ and 5.5,respectively.The xylanase was stable when pH was 4.5-5.5.Its activity was activated by Ca2+,Fe2+,Na+ and Tween80,inhibited by Mn2+,Tris,EDTA,urea and SDS,while Cu2+ and K+ had a little effect on its activity.Conclusion] The study selects a high xylanase yielding Monascus pupureus bacterium strain,to enlarge the range of strain producing xylanase.