Microbial-enzymatic-hybrid biological fuel cell with optimized growth conditions for Shewanella oneidensis DSP-10

•Hybrid biological fuel cell based on the oxidation of lactate by microorganisms at the anode and oxygen reduction by enzymatic cathode including initial material investigation of the anode.•Shewanella oneidensis DSP-10 anode and Laccase air breathing cathode.•Varying growth conditions of microorganisms for optimized current density and discussion of observed growth condition for biofilm formation.•Silica encapsulation of biomass for device development and study.

In this work we present a biological fuel cell fabricated by combining a Shewanella oneidensis microbial anode and a laccase-modified air-breathing cathode. This concept is devised as an extension to traditional biochemical methods by incorporating diverse biological catalysts with the aim of powering small devices. In preparing the biological fuel cell anode, novel hierarchical-structured architectures and biofilm configurations were investigated. A method for creating an artificial biofilm based on encapsulating microorganisms in a porous, thin film of silica was compared with S. oneidensis biofilms that were allowed to colonize naturally. Results indicate comparable current and power densities for artificial and natural biofilm formations, based on growth characteristics. As a result, this work describes methods for creating controllable and reproducible bio-anodes and demonstrates the versatility of hybrid biological fuel cells.