离子注入选育高产木聚糖酶黑曲霉及其发酵条件研究

MUTATION BREEDING OF XYLANASEHIGH-YIELDING STRAIN OF ASPERGILLUS NIGER BY IONS IMPLANTATION AND STUDIES OF ITS FERMENTATION CONDITIONS OF THE STRAIN

以黑曲霉A3为出发菌,利用离子注入技术选育出一株遗传性状稳定的木聚糖酶高产突变株AN497,其产酶水平较出发菌从野生型A3菌株的405.6IU/ml提高到586.2IU/ml,即酶产量增加了44.5%;对高产菌进行发酵条件优化,发现以玉米芯粉为主要碳源、用蔗糖代替葡萄糖作为附加碳源,对木聚糖酶的发酵具有明显的促进作用;采用复合的无机氮源 (NH4)2SO4和NaNO3,(1: 2)浓度以10g/L为宜;菌株对发酵通氧量具有较高的要求,摇瓶转速在230r/min时的产酶水平较200r/min要高;通过发酵条件的优化,高产菌株的产酶活力最高可达671.1IU/mL,比出发菌株的产酶量提高了65.5%。

A mutant AN497 was screened from wild strain of Aspergillus niger A3 by the technology of ion implantation. The xylanase activity of AN497 is 586.2IU/mL, it increased by 44.5 % as compared with A3 under the same conditions.Through optimizing the fermentation conditions of the high-yielding strain , the activity of xylanase was remarkably promoted by using corncob powder as main carbon source and cane sugar as additional carbon source substituting glucose. The optimal nitrogen source, (NH4)2 SO4 and NaNO3 (1 : 2) is 10g/L. The maximal xylanase activity reached 671.1IU/mL under the optimal conditions.