利用曲霉sp.HS-6发酵玉米秸秆进行固体纤维素酶的制备

以玉米秸秆为原料,分别以氯化铵、硫酸铵、硝酸铵、硝酸钾和尿素为氮源,设置了氮源的3个浓度梯度:0.5、1和2 g·L-1,对曲霉sp.HS-6产纤维素酶条件进行探究,主要确定了最佳发酵时间、最佳氮源种类和最佳氮源浓度,再利用得到的最佳条件,进行盐析,低温冷冻干燥等技术发酵得到酶制剂。结果表明,通过测定酶活,确定了该曲霉的最佳发酵时间为3 d,筛选得到最佳的氮源种类为硝酸铵,硝酸铵最佳的氮源浓度为0.5 g·L-1。基于此最佳条件,将60 g玉米秸秆粉末发酵培养3 d,最终从发酵液中提取得到纤维素酶干品酶制剂8.0 g,并计算出酶的回收率为48.0%。此实验对以后纤维素酶的规模化制备提供了一定的工艺参考。

Production of solid cellulose through fermentation of maize straw by Aspergillus sp. HS-6

In this paper, we explored the production conditions of cellulase through fermentation of maize straw by Aspergillus sp.HS-6 with the addition of NH₄Cl, (NH₄)₂SO₄, NH₄NO₃, KNO₃, and CO(NH₂)₂ as nitrogen sources at three concentrations (0.5, 1 and 2 g·L^-1). The optimal fermentation time, the optimal nitrogen source and Aspergillus sp.HS-6 concentration were determined. Based on the optimum fermentation conditions, salting-out and freeze-drying techniques were used to produce solid enzymes. The results showed that: the optimal fermentation time was 3 days by determining the enzyme activity and the optimal nitrogen source was NH₄NO₃ at 0.5 g·L^-1. Under this condition, we obtained the product of solid cellulase with a recovery rate of 48.0%. This experiment would provide some references for a large-scale production of cellulase in the future.