Multifunctional fluorocarbon photobioreactor system: a novel integrated device for CO2 segregation, O2 collection, and enhancement of microalgae growth and bioproductions.

Abstract

An enhanced greenhouse effect due to high CO2 emissions has become one of the most concerning issues worldwide. Although plant/algae-mediated approaches have been extensively used for CO2 segregation in the last decades, these methods are generally aimed at environment protection. In contrast, less attention has been given to CO2 manipulation that has regrettably caused a decrease in the commercial availability of the associated technologies. To generate a system for practical use, a synthetic fluorocarbon photobioreactor system (FCPBRS) consisting of a CO2 isolation unit, a gas modulation unit, an O2 collection unit, and a microalgal culture chamber was developed in this study. After injecting a 60%-N2/40%-CO2 gas mixture into the CO2 isolation unit for 10days, the results showed that the FCPBRS enabled a > 93% CO2 separation efficiency using a fluorocarbon liquid FC-40 as the CO2 adsorbent. In addition, the growth rate of Nannochloropsis oculata was significantly enhanced when cultured with 20mLmin-1 of the FC-40 flow containing 2% CO2 throughout the time course, resulting in 4.7-, 4.6-, and 4.5-fold (P < 0.05 for each) increases in biomass, total lipid, and eicosapentaenoic acid yields, respectively, compared to the aerated group without FC-40. Moreover, approximately 1600mL of photosynthetic O2 with a ~ 80% collection efficiency was obtained in the O2 collection unit within 10days of FCPBRS operation. These outcomes indicate that the FCPBRS may provide a feasible means to simultaneously achieve CO2 isolation, O2 collection, and enhanced microalgae bioproductions.