Abstract
Cyanobacteria are oxygenic photosynthetic prokaryotes with a wide morphological diversity with some members capable of fixing atmospheric N 2 . This paper reports on the taxa isolated and cultured from water in selected reservoirs in the Dry, Intermediate and Wet zones of Sri Lanka with the potential of utilizing them for biofuel and other industries including cosmetics. Water samples were concentrated by filtering through plankton net and re-suspended in 50 mL of either in respective reservoir water samples or in distilled water. Aliquots of these were cultured in blue green 11 (BG 11) and GO (same as BG11 media but N-free) media. Cultures were maintained under 2,000 lux light intensity with shaking at 200 rpm. A total of 64 cyanobacterial cultures, isolated by repeated sub-culturing in liquid and agar media, were observed under a light microscope for identification. While 16 different taxa were isolated from the Dry Zone, 12 and 5 taxa were isolated from the Wet and Intermediate zones, respectively. The frequency of isolating Oscillatoria sp. was high (10 reservoirs) followed by Microcoleus sp. and Microcystis sp. (each from 6 reservoirs). A strong positive correlation was recorded between cyanobacterial occurrences with abiotic properties such as water temperature, pH and secchi depth (turbidity). Samples prepared in water from respective reservoirs gave faster growth during culturing than those prepared in distilled water. The occurrence, availability and culturability of the isolates obtained in the present study will be useful in the development of value-added cyanobacterial products and cyanobacteria-based industries including biofuel.
Highlights
Cyanobacteria constitute a morphologically diverse and widely distributed group of gram-negative photosynthetic prokaryotes (Pandey, 2015)
The present study reports on the isolation, culturing and identification of cyanobacteria from some selected fresh water reservoirs located in three major climatic zones of Sri Lanka, with the aim of identifying suitable taxa for bio-fuel production and other industries
The number of sampling reservoirs was found to be positively correlated with number of cyanobacteria isolated from three climatic zones (Table 1)
Summary
Cyanobacteria (blue-green algae) constitute a morphologically diverse and widely distributed group of gram-negative photosynthetic prokaryotes (Pandey, 2015). The ability of some of these organisms to fix N2 either independently or in symbiosis with other organisms contributes to natural ecosystems but is used in certain countries as a biofertilizer in rice cultivation (Kulasooriya, 2012) These qualities make cyanobacteria one of the most successful and widespread group among the prokaryotes, occupying a wide range of terrestrial and aquatic environments (Shatheesh, 2013). Cyanobacteria are characterized with their high morphological diversity not seen among other prokaryotes This extends from unicellular to filamentous species with a cell volume ranged over more than five orders of magnitude (Whitton, 2000). Photosynthetic cyanobacteria have drawn significant attention as they can serve as important sources for cosmetic, food and pharmaceutical products, industrial materials and even in biofuel production
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
