Enhancement of CO2 biofixation and bioenergy generation using a novel airlift type photosynthetic microbial fuel cell

Abstract

This study developed a novel airlift type photosynthetic microbial fuel cell (AL-PMFC) using Chlorella vulgaris to enhance the CO2 biofixation and bioenergy (bioelectricity and biodiesel) generation. The performances of AL-PMFC in CO2 fixation rate, lipid accumulation and power output were investigated and compared with a bubbling-type photosynthetic microbial fuel cell (B-PMFC). Due to the enhanced mass transfer, the CO2 fixation rate of AL-PMFC reached 835.7 mg L−1 d−1, 28.6% higher than that of B-PMFC. Besides, the analysis of energy balance indicated that a maximum net energy of 2.701 kWh m−3 was achieved in AL-PMFC, which performed better than B-PMFC. After optimization of C. vulgaris inoculum density, CO2 concentration and aeration rate, the maximum CO2 fixation rate, lipid productivity, and power density in AL-PMFC reached 1292.8 mg L−1 d−1, 234.3 mg L−1 d−1, and 5.94 W m−3, respectively. The AL-PMFC provided an attractive approach for CO2 fixation and bioenergy generation.