Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8327276 | International Journal of Biological Macromolecules | 2018 | 52 Pages |
Abstract
Isolated strain Aspergillus niger WA 2017 was selected as potential protease producer and was identified on the basis of 18S rDNA gene homology. Optimization of protease production conditions was performed using statistical methodology. The most significant factors were identified by Plackett-Burman design (PB) and were optimized by Central Composite design (CCD). The enzyme production was increased by 3.6-fold with statistically optimized medium when compared to the basal medium. Based on the protease activity, 25-50% ethanol fraction exhibited the highest specific activity. The partially purified enzyme showed its highest activity (4.7-fold) after 10â¯min incubation at pHâ¯10.0 and 60â¯Â°C. The enzyme was stable over a wide range of pH (7-11) and salt concentration (up to 20%). Kinetic parameters Michaelis constant (Km) and maximum velocity (Vmax) were calculated at varying casein concentrations. Additionally, thermal stability of the enzyme was substantially improved by NaCl. The enzyme showed excellent stability and compatibility in presence of organic solvents and detergents retaining 115.3 and 114.5% of its activity in presence of ethanol and Tide, respectively at 40â¯Â°C for 1â¯h. The results revealed that the produced enzyme was able to recover silver from used X-ray film under optimized condition using statistical methodology (CCD).
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Authors
Walaa A. Abdel Wahab, Samia A. Ahmed,