A Microbial Fuel Cell with a Photosynthetic Microalgae Cathodic Half Cell Coupled to a Yeast Anodic Half Cell

Abstract

A recently developed photosynthetic cathodic half cell has been coupled to a fermentative anode to produce a complete microbial fuel cell. The photosynthetic organism Chlorella vulgaris was employed as the electron acceptor in the cathodic half cell with the yeast strain Saccharomyces cerevisiae serving as the electron donor in the anodic half cell. Maximum power was observed at 90 mV and a load of 5000 Ω, giving a power density of 0.95 mW/m² of electrode surface area. The effect of changing culture conditions on fuel cell operation is reported. A maximum open circuit voltage of 315 mV was achieved with the addition of supplemental glucose to the anodic half cell. Enriching the feed air bubbled into the cathode half cell with 10% CO₂ increased the open circuit voltage by a factor of 1.5 compared to using pure air as the feed gas. Since photosynthetic microbial growth at the cathode of the MFC consumes CO₂, this complete microbial fuel cell is CO₂ neutral and produces both electricity and ethanol as valuable energy products.

Keywords:

• anode
• cathode
• microalgae
• microbial fuel cell
• photosynthesis
• yeast