MASS CULTURE OF APHANIZOMENON FLOS-AQUAE RALFS EX BORN. AND FLAH. VAR. FLOS-AQUAE (CYANOBACTERIA) FROM KLAMATH FALLS, OREGON, USA, IN CLOSED CHAMBER BIOREACTORS.

Aphanizomenon flos-aquae Ralfs ex Born. and Flah. var. flos- aquae (Cyanobacteria) was sampled from Upper Klamath lake and subjected to batch culture of 15-litre bioreactors. Growth characteristics viz. doubling time (Dt), specific growth rate (µ), temperature requirement, biomass and chlorophyll-a concentrations were studied during exponential growth phase at a fixed light intensity of 40-45 micromole in a CT medium. CT growth medium when supported by CO2 from a chemical byproduct in a connected chemical reactor resulted in better growth characteristic than either ASM or ASM-1 in literature. A relationship of dry weight (dw) and absorbance of the culture in CT medium was developed for calculations without the absolute need of the time-consuming dry weight measurements. Maximum measured dry weight obtained at this growth condition after 120 hours is 151 g/m 3 . The best growth temperature studied in this work is 20 o C with a supply of CO2. Results are compared with previous findings in the literature and recommendations are made for mass cultivation.