Yang S S, Chiu W F
Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi. 1986 Nov;19(4):276-88.
The sweet potato residue being at the initial moisture content 50-58%, initial pH 3.5-4.3, supplemented with rice bran, and minerals, and incubated at 20-26 degrees C for 5 days was the optimal conditions for protease production with Aspergillus niger NTU-AM-1 by solid state fermentation. Protease could be recovered by shaking at room temperature for one hour and extracted with five times volume of 0.1% NaCl solution. The yield of protease was 814 units per gram dry weight of substrate. Partially purified protease with DEAE-Sephacel column chromatography was thermally stable and able to retain 80-100% of activity in pH 4.0-5.5 at 55 degrees C for 40 minutes. In addition, the activity of protease was stimulated by the presence of EDTA and cysteine, but was inhibited by the addition of HgCl2.
初始水分含量为50 - 58%、初始pH值为3.5 - 4.3、添加米糠和矿物质并在20 - 26摄氏度下培养5天的甘薯残渣，是黑曲霉NTU - AM - 1固态发酵生产蛋白酶的最佳条件。蛋白酶可通过在室温下振荡1小时回收，并用5倍体积的0.1%氯化钠溶液提取。蛋白酶的产量为每克干重底物814单位。用DEAE - Sephacel柱色谱法部分纯化的蛋白酶具有热稳定性，在55摄氏度下于pH 4.0 - 5.5中40分钟内能保留80 - 100%的活性。此外，蛋白酶的活性受到EDTA和半胱氨酸的刺激，但添加HgCl2会抑制其活性。
