Development of synthetic perfluorinated photobioreactor system for simultaneous carbon dioxide separation and promotion of microalgae growth and productions

BACKGROUND: CO₂ is the primary impurity in many fuel gases and may reduce the efficiency of fuel combustion and generate incomplete residues in the product, leading to energy waste and environmental issues after emission. Currently although plants/microalgae-mediated approaches have been widely used for CO₂ separation/digestion, they usually emphasize CO₂ removal efficacy for the purpose of environment protection, but give less consideration to subsequent CO₂ manipulation for cell culture that restricts their effectiveness thereafter. To address the above issues, a perfluorinated photobioreactor system (PPBRS) enabling CO₂ separation and controlled microalgae cultivation was developed in this study. RESULTS: Results showed that the PPBRS provided >85% CO₂ separation efficiency from 60%-N₂/40%-CO₂ within 5 days by using perfluorocarbon as the CO₂ absorbent. Nannochloropsis oculata cultured with 20 mL min^-1 perfluorocarbon containing 2% CO₂ isolated from the gas mixture exhibited 2-fold higher cell concentration and yielded 1.8-, 2.5-, and 2-fold (P < 0.05 for all) increased productions of biomass, lipid, and eicosapentaenoic acid, respectively, compared with the group with air aeration without PFC for 5 days. CONCLUSION: Perfluorocarbon is recyclable and all procedures including CO₂ extraction, collection of purified gas, and delivery of isolated CO₂ to cell culture are a continuous process without need for additional handling. The PPBRS thus provides an efficacious, easy-to-use, and cost-effective means for simultaneous CO₂ separation and enhanced microalgae production that can be applied for use in industry.