Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Microbiology

Cyanobacteria constitute a vast potential resource in various applications such as pharmaceutical, agriculture, food, feed, fuel, fertilizer, industry and in combating pollution. In this study, the biodiversity of aquatic cyanobacteria was monitored in various water resources representing those of the River Nile at Giza and Ain Sokhna, Red sea in Egypt as well as some United Arab Emirates water supplies. Total number of six isolates were secured and subjected for morphological and microscopic examinations. Three isolates representing the most common members were identified using the molecular biology techniques. Those were closely related to the genera Anabaena sp., Oscillatoria sp. and Synechocystis sp. of the Gene Bank. They were evaluated for their potential capacities as anti-fungal and anti-bacterial agents as well as measuring their anti-oxidant activities. The examinations of hexane, methanol, chloroform and diethyl extracts of the tested cyanobacterial cultures indicated the presence of several metabolites including 9-hexadecenoic acid, leukotriene C4, neophytadiene, phthalic acid, hexadecanoic acid, octadecenoic acid, octasiloxane hexadecamethyl, phytol acetate, octadecadienoyl chloride and cyclohexasiloxane dodecamethyl. Adopting the disk diffusion method, the cyanobacterial extracts as anti-bacterial substances arranged the examined cultures in the descending order of Anabaena > Synechocystis > Oscillatoria with inhibition zone averages of 11.3, 10.7 and 10.3 mm, respectively. Similarly, the experimented microbiota considerably varied in their anti-fungal capabilities where the cyanobacterium Anabaena seemed the most active one. In respect to the anti-oxidant activity, Oscillatoria was the pioneer among the other tested ones. All in all, this study supports the applicability of such very unique aquatic creatures in the biotechnological approaches and pharmaceutical ones in particular

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