2.2. Sample collection
Totally 12 water and 12 sediment samples were collected from Gorgora site of Lake Tana which was located at 65 km North West direction of Gondar town. The water samples were collected in 500 mL sterile screw capped bottles and sufficient space was provided for aeration and thorough mixing. The sediments were collected by sterilized spatula and transferred to wide mouth sterilized bottle. All samples were labeled and transported to Microbiology Laboratory, Department of Biology, University of Gondar and stored at 4 °C for further studies.