الفهرس Only 14 pages are availabe for public view
 |  | from | 210 |  |  |
| | | from | 210 | | |
Abstract
In the present Investigation six bacterial strains were tested for their abilities to produce active and thermostable alkaline protease. B. stearothermophilus was found to be the most potent alkaline protease producer and therefore it was used throughout this study. The effect of some cultural conditions on the productivity of the enzyme by B. stearothermophilus was investigated. Partial purification of enzyme was achieved by fractional precipitation of the crude enzyme by ethanol, ammonium sulfate and tannic acid. The ethanol fraction precipitated at 75% exhibited the highest recovered activity. This fraction was used for the succeeding part of the work. Some properties of the partially purified enzyme were investigated. Chemical modification of enzyme by covalent coupling to soluble polysaccharides has been reported as a common technique for improving its properties especially thermal stability. The enzyme coupled to activated pectin showed the highest thermal stability and retained the highest specific activity. The properties of the native and conjugated enzyme were compared. The enzyme was immobilized on Insoluble supports by covalent binding. Of all tested carriers, the immobilized enzyme on nylon showed the highest immobilization yield and the highest immobilized activity. The properties of the free and.