VATIS UPDATE Article

The U.S. Naval Research Laboratory (NRL), Center for Biomolecular Science and Engineering (CBSE), has received a U.S. patent for a self-assembling, self-repairing, and self-contained microbial photoelectrochemical solar cell driven entirely by sunlight and microorganisms. A solar microbial fuel cell (SMFC) is a non-semiconductor-based system, which employs microorganisms to generate electric power by photosynthetically replenishing reactants of a sealed microbial fuel cell using sunlight.

The SMFC reactants (glucose and oxygen) are internally regenerated by a group of photosynthetic microbes whose reactants, carbon dioxide (CO2) and water (H2O), are the products of the microbial fuel cell. This interdependency results in many thousands of hours of long-term electricity generation from sunlight without replenishment of the microbial fuel cell reactants. “Natural photosynthetic systems, such as trees and algae blooms, self-repair, a property that makes them highly durable,” said Dr. Lenny Tender, at CBSE.

The BMFC generates electrical power by oxidizing organic matter (fuel) residing in sediment pore water with oxygen (oxidant) in overlying water, and consists of an anode imbedded in the marine sediment connected by an external electrical circuit to a cathode positioned in overlying water. Unlike the open marine-based BMFC generator, the SMFC apparatus does not require an endless flux of reactants from sediment and seawater to persistently generate power, but instead, recycles the organic matter sealed within the unit to regenerate the reactants.