GROWTH AND ECONOMICAL RETURN OF CHLORELLA VULGARIS UNDER DIFFERENT CARBON SOURCES

The green alga Chlorella vulgaris was laboratory grown under different nitrogen and carbon sources aiming at the determination of growth potential of alga as well as the most economical and proper carbon source. Firstly, alga was grown under the laboratory optimal conditions using the recommended BG-11 growth medium. Two different nitrogen sources (NO3 and NH3) were firstly examined to determine the alga growth curve under the ambient conditions at 17.6 mM N. For the next comparison, alga was incubated with urea, organic carbon (vinasse waste); ammonium carbonate and sodium acetate based on the initial urea carbon content (106 ppm). Growth was operated within the fully transparent Plexi-Glass photobioreactor (108L capacity). The investigated parameters were dry weight and pigments. The obtained biomass was then analyzed for economic return. Data revealed the approximately similar effect of both nitrogen sources in concern dry weight and carotenoids, while nitrate markedly increased chlorophyll content. As for carbon source, organic carbon increased dry weight and carotene content, and sodium acetate increased chlorophyll content. Maximum dry weight was obtained with cultures grown with organic carbon (1.72 g.l-1); while chlorophyll was maximized with acetate carbon 62.89 mg.l-1 and 29.19 mg.l-1 of carotenoids were obtained with organic carbon. Biochemical analysis of the obtained biomass as for the obtained biomass verses to the net volume, economic evaluation organic carbon recorded the lowest production cost per kg of Chlorella biomass per each kg of biomass in concern nitrogen and carbon source under mixotrophic carbon nutrition.