Bioelectricity generation using sulphate-reducing bacteria as anodic and microalgae as cathodic biocatalysts

Abstract

ABSTRACTBecause microalgal species carry out oxygenic photosynthesis, they can be employed in the cathode chamber of microbial fuel cells, thus negating the need for mechanical aeration for oxygen reduction reactions. A conventional H-shaped configuration is used for comparative analysis of bioelectricity generation using pure and mixed microalgal cultures. Three reactors are simultaneously inoculated with sulphate-reducing bacteria as anodic and mixed culture of microalgae (MA#1) and two pure species in the cathodic chamber in separate reactors (MA#2; MA#3). Maximum open circuit potentials of 670, 476 and 529 mV are achieved with MA#3, MA#2 and MA#1, respectively. Power densities on the order of 442.5, 69 and 135 mW/m3 are obtained for microalgal cultures MA#3, MA#2 and MA#1, respectively. The highest power and current density values are obtained with MA#3 inoculated with pure algal species. The algal species are also examined for their lipid content with the use of Fourier transform infrared spectroscopy, Nile red spectroscopy and lipid content analysis. A good amount of lipid content is shown in spectroscopy images. Biomass content is highest for the algal consortium (MA#1) whereas lipid content is best in the case of pure algal species (MA#2).