Ogundero V W, Osunlaja S O
J Basic Microbiol. 1986;26(4):241-8. doi: 10.1002/jobm.3620260415.
Optimal growth and extracellular protease production by Aspergillus clavatus Des. was recorded at 30 degrees C and between days 5 and 7 of the 8-day incubation period. Purification of this enzyme was achieved by a combination of ultrafiltration, alcoholic precipitation and fractionation on DEAE-cellulose and Sephadex-G.200. A single peak of an alkaline protease was subsequently obtained with a 9-fold increase in specific activity and a final recovery value of 26.2%. The enzyme had optimal activity at 37 degrees C and a pH of 7.8. The enzyme did not degrade leucine amide, hippurylphenylalanine and hippurylarginine indicating lack of exo-protease activity. However, endo-protease activity led to a rapid hydrolysis of gelatin with optimal activity at 40 degrees C and pH 7.8. The high incidence of A. clavatus on Nigerian poultry feeds vis-a-vis the potential health risks posed to farm animals is discussed.
棒曲霉在30℃以及8天培养期的第5至7天实现了最佳生长和胞外蛋白酶的产生。通过超滤、酒精沉淀以及在DEAE-纤维素和葡聚糖G-200上的分级分离相结合的方法对该酶进行了纯化。随后获得了一个碱性蛋白酶的单峰，比活性提高了9倍，最终回收率为26.2%。该酶在37℃和pH 7.8时具有最佳活性。该酶不会降解亮氨酸酰胺、马尿酸苯丙氨酸和马尿酸精氨酸，表明缺乏外切蛋白酶活性。然而，内切蛋白酶活性导致明胶快速水解，在40℃和pH 7.8时具有最佳活性。文中讨论了尼日利亚家禽饲料中棒曲霉的高发生率以及对农场动物造成的潜在健康风险。
