| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 97 === Microalgae have received much attention as renewable energy resources, since the photoautotrophic mechanism can convert the atmospheric carbon dioxide into biomass. In order to harvest microalgae with the high productivities of biomass and lipid, design of experiments with regression analysis was applied to optimize the culture conditions of medium. Under the mentioned optimal culture conditions, a continuous culture process was purposed to carry out for harvesting microalgae continuously.
In this study, the design of experiments was defined to investigate the effects of initial nitrogen concentration, light intensity, carbon dioxide aeration rate and salinity on the growth and lipid formation of Chlorella sp.. Using regression analysis, the optimal culture conditions for the highest lipid productivity were estimated as 0.2 g/L of nitrogen concentration, 1200 μmol photon m-2 s-1 of light intensity, 2.86% of carbon dioxide aeration rate and 18.75 g/L of salinity. These conditions were verified experimentally, since the productivities of the biomass and lipid achieved to 0.465 and 0.175 g/L-day, respectively.
For knowing the growth kinetics and lipid formation of Chlorella sp., Logistic and Luedeking-Piret equations are considered as the models to approach the dynamics. These two kinetic models were further employed to predict the optimal dilution rate associated with the biomass and lipid concentration as 0.9253 and 0.7526 day-1, respectively. Under the optimal operating conditions, an experimental verification was carried out, and a reasonable good agreement between experimental data and model prediction is observed by the relative error of -10.53% and R squared of 0.9701. Therefore, the chemostat strategy with optimal operational condition is successfully employed for producing microalgal bioproduct.
|
|---|
