Effects of Nitrogen Availability on the Bioenergy Production Potential and CO2 Fixation of Thermosynechococcus CL-1 under Continuous Cultivation

Chih Ming Su ； Hsin Ta Hsueh ； Hsing Hui Chen ； Hsin Chu1

《Aerosol and Air Quality Research》 13卷4期 (2013/08) Pp. 1321-1330+1-3

並列摘要

Nitrogen availability directly affects the microalgal metabolism. A thermophilic cyanobacterium named Thermosynechococcus CL-1 was cultivated in a continuous system to evaluate the effects of NO3^- fluxes on the biomass production, bioenergy production, and CO2 fixation. The results show that decreasing the NO3^- flux to a N-deprived level (1.01 mM/d) enhances the carbohydrate content in TCL-1 to 45%, accompanied by a decrease in the lipid content. However, increasing the NO3^- flux from a N-deprived level (1.01 mM/d) decreases the carbohydrate content dramatically, accompanied by a slight increase in the lipid content. No matter whether the NO3^- flux decreases from a N-replete level (8.35 mM/d) to a N-deprived one (1.01 mM/d), or increases from a N-deprived level to higher one, the peak biomass yield occurs at the same NO3^- flux level, 4.18 mM/d. In addition, the peak lipid yield, carbohydrate yield, and CO2 fixation rate were recorded at 482 and 660 mg/L/d, and 3.9 g/L/d, respectively, under the same NO3^- flux level (4.18 mM/d). Although cultivating TCL-1 under the 4.18 mM/d NO3^- flux level exhibits great biomass production, CO2 fixation, and bioenergy production potential, different procedures (the NO3^- flux decreasing from the N-replete level and the NO3^- flux increasing from the N-deprived level) could influence the final quantity of bioenergy production and CO2 fixation. The NO3^- flux, NO3^- concentration in the bioreactor, and the NO3^- flux variation routes are all important factors to determine the nitrogen availability of TCL-1 in continuous cultivation.

並列關鍵字

Nitrogen availability ； Thermosynechococcus ； Continuous operation ； Bioenergy ； CO2 fixation