Studies on Adaptive Strategies of an Un-identified blue Green alga Isolated from Freshwater Husain Sagar lake

摘要

An alga was isolated from enrichment culture of anaerobic sulfate reducing bacteria of bottom waters of highly eutrophicated and polluted Husainsagar lake, Hyderabad, Pure algal colonies were obtained on modified Chu 10 agar media plates after growingthe alga in broth media supplemented with antibiotics and repeated washing with 8.5% saline. Growth characteristics of the alga were observed in modified Chu 10, Green sulfur bacterial media and Postgate 'B' medium at optimum pH 7.5 and temperature 26°C under illumination of 2000 Lux in butyl rubber stoppered bottles, Oxygen evolution studies were carried out using oxygen electrode. Studies indicated that this alga is an unicellular non nitrogen fixing, obligate phototroph. It is capable of growing aerobically with mineral media, tolerating 2.5 mM Na_2S concentration. It is growing aerobically and anaerobically and showed low respiration and photosynthetic rates in Postgate 'B' medium indicating it's photoheterotrophic mode of nutrition. It is a DCMUresistant tolerating up to 50 uM and showed 34% of inhibition of net oxygen evolution. The results indicate that the organism is capable of growing autotrophically and heterotrophically using lactate as chief carbon source under adverse conditions prevailing at deeper layers of the lake.