ASTRI RINANTI, EDWAN KARDENA, DEA INDRIANI ASTUTI AND KANIA DEWI
Abstract
Culture conditions are very important to CO2 bio-fixation but its implementation is limited by the poor mass transfer efficiency. The three green microalgae, i.e. Chlorella, Scenedesmus obliquus, and Ankinstrodemus sp were cultured as co-culture in a vertical bubble photobioreactor as closed system, with 160 μm size diameter of pore membrane sparger to explore the possibility of coupling CO2 biofixation affected the carbon mass transfer process. In this study, overall volumetric mass transfer coefficient (KLa) of CO2 were developed with operational culture conditions at temperatures (0C) of 30, light intensities (lux) of 4000 and photoperiodism (light/dark; hour) of 16/8, with various high concentration (%) CO2 supplied from the bottom of photobioreactor were 0, 2, 5, 7. The result showed that the highest KLa value (h-1) was 0.1419 5% pure CO2 supplied, gas flow rate 8 L/min during 12 days experiment. While at this condition, the maximum dried biomass (g/mL) was 2.7 (μ = 0.38) at 5% pure CO2. It could be concluded that CO2 removal efficiency (%) affected by the KLa value, whereas the highest CO2 removal efficiency (%) of 49.02 occurred when the Kla value was highest.