CARBON DIOXIDE FIXATION BY CO-CULTURE GREEN MICRO ALGAE THROUGH OVERALL VOLUMETRIC MASS TRANSFER COEFFICIENT (KLA) OF CARBON DIOXIDE INCLOSED SYSTEM

摘要

Culture conditions are very important to CO_2 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 avertical bubble photobioreactor as closed system, with 160 ji,m size diameter of pore membrane sparger to explore the possibility of coupling CO_2 biofixation affected the carbon mass transfer process. In this study, overall volumetric mass transfer coefficient (KLa) of CO_2 were developed with operational culture conditions at temperatures (°C) of 30, light intensities (lux) of 4000 and photoperiodism (light/dark; hour) of 16/8, with various high concentration (%) COz supplied from the bottom of photobioreactor were 0, 2, 5, 7. The result showed that the highest KLa value (h1) was 0.1419 5% pure CO_2 supplied, gas flow rate 8 L/min during 12 days experiment. While at this condition, the maximum dried biomass (g/mL) was 2.7 (u = 0.38) at 5% pure CO_2. It could be concluded that CO_2 removal efficiency (%) affected by the K_La value, whereas the highest CO_2 removal efficiency (%) of 49.02 occurred when the F^a value was highest.