Thesis (M.Sc.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Egyptian aquatic bacetrioplankton is of highly positive impact due to the various aquatic systems of this country. Although the bacterial community found in the seawater with its salty nature may be different from those of freshwater in rivers and lakes, most of those areas are still untapped. Water samples from different Egyptian aquatic environments (Red Sea, Alexandria Saltern and Lakes of Wadi EL Rayan, Wadi AL Natrun and Qarun) were screened for extremophilic bacterial strains using different modified cultivation media. The aim of this work was to isolate novel useful extremophilic bacterial strains with various enzymatic activities that may allow their use in industrial, agricultural and biotechnological fields. Eighty isolates were obtained including 69 bacterial isolates and 11 fungal ones. The isolates showed great variation in their pH and salt requirements and hence they could be categorized into four different groups; moderately halophilic (10% NaCl & pH 7), extremely halophilic (22.5% NaCl & pH 7.5), haloalkaliphilic (10% NaCl & pH 9) and alkaliphilic (0% NaCl & pH 8.7).Upon testing their enzyme production capability, they showed cellulase, amylase and DNase activities in 51.25 %, 46.25% and 26.25% of the isolates; respectively, but no lipase activity was observed

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