Revista de Bioprocessamento e Biotécnicas

Power Generation by Algal Microbial Fuel Cell Along with Simultaneous Treatment of Sugar Industry Wastewater

Abstract

Tanisha Manchanda*, Rashmi Tyagi, Vijaya Kumar Nalla, Suman Chahar and Durlubh Kumar Sharma

Algal biotechnology has gained interest world over as it is a better resource in comparison to land biomass. One interesting emerging application is its utilization in microbial fuel cells (MFCs) for the production of electricity while utilizing these algae for the treatment of industrial wastewater besides hydrocarbons and lipid production later. Presently, the potential of two strains of an oil-rich green alga Botryococcus braunii has been studied for its utilization in microbial fuel cells. Photosynthetic algal strains in various media in the cathodic half of the MFCs provided a continuous source of oxygen from their photosynthesis to serve as electron acceptor. This helped in reducing the cost of energy needed for mechanical aeration to enrich the catholyte with oxygen as electron acceptor. These cathodic half cells were combined separately with three different anolytes, firstly Saccharomyces cerevisiae culture alone, secondly, Saccharomyces cerevisiae culture supplemented with the mediator methylene blue (350 mg/L) and thirdly, sugar industry wastewater mixed with activated sludge. Amongst MFCs consisting of various combinations of these catholytes and anolytes, highest values of power density (7.27 μW/cm2) and current density (20.87 μA/cm2) were observed with Saccharomyces cerevisiae culture supplemented with methylene blue as the anolyte and B. braunii in soap industry wastewater as the catholyte. Present study demonstrates the potential of the coupling of cultivation of photosynthetic B. braunii for biodiesel production with the wastewater treatment plant as a sustainable source of electricity in microbial fuel cells.