الفهرس 
صفحة العنوانOnly 14 pages are availabe for public view
 |  | from | 178 |  |  |
| | | from | 178 | | |
Abstract
Abstract
Thirty-four bacterial isolates were isolated from soil samples collected from the North Western Coast and a water sample collected from brackish water at Siwa Oasis, Matrouh Governorate, Egypt. Only six isolates showed chitinase activity, when screened on colloidal chitin agar medium. The highest chitinolytic activity was achieved by a bacterial isolate labeled as A.S. This isolate was identified as
Aeromonas hydrophila based on analysis of 16S rRNA gene sequence & morphological, physiological and biochemical characteristics.
Optimization of the cultural conditions for maximum chitinase
production by A. hydrophila revealed that the highest level of chitinase
was recorded when the bacterium was grown in malt nitrogen based medium containing (1 % colloidal chitin) at pH 7 for 48 h incubation at 30oC. Crude chitinase from isolate A. hydrophila was evaluated
against first instar larvae of the greater wax moth; Galleria mellonella
L. (Lepidoptera: Pyralidae) at different concentrations of (0, 185, 205,
235, 265, 295 U/mg) protein. It increased larval and pupal mortality rates in a concentration-dependent manner. The tested crude chitinase significantly induced a decrease in adults’ emergence rate and their
fecundity.