米曲霉RIBl28耐酸性木聚糖酶的研究

Study on An Acid-Stable Xylanase from Aspergillus oryzae RIB128

通过RBB—Xylan筛选平板和固体培养方法获得了产木聚糖酶菌株米曲霉 (Aspergillusoryzae)RIBl2 8.在液体发酵时木聚糖是有效的诱导底物 .通过离子交换和凝胶过滤色谱纯化得到了一个耐酸性木聚糖酶 (木聚糖酶B) .它的相对分子质量为 6 5 0 0 0 ,最适作用温度和 pH分别为 5 5℃ (pH 6 .5 ) ,它在 5 0℃时很稳定 ,并且在 pH 2 .0时仍保留相当高的活性 .木聚糖酶B含有较多的天冬氨酸、丝氨酸、苏氨酸和丙氨酸 .

Aspergillus oryzae RIBI28 was isolated from Aspergillus oryzae strains as the xylanase producer by the methods of RBB Xylan media and solid state culture. Xylan from oat spelts is the effective inducing substrate for xylanase producing by submerged culture. An acid stable xylanase (Xylanase B) was purified by ion exchange and gel filtration chromatographies. The molecular weight of xylanase B estimated by SDS PAGE was 65 000. The optimum temperature of Xylanase B was 55 ℃. The optimum pH was pH 6.5. XylanaseB was more stable in acidic condition (pH 2.0) and contains large amounts of aspartic acid, serine, threonine, and alanine.