Electrogenic Single‐Species Biocomposites as Anodes for Microbial Fuel Cells

Abstract

Integration of electrogenic microorganisms remains a challenge in biofuel cell technology. Here, synthetic biocomposites ("artificial biofilms") are proposed. Bacteria (Shewanella oneidensis) are embedded in a hydrogel matrix (poly(vinyl alcohol)) via wet- and electrospinning, creating fibers and nonwoven gauzes. The bacteria remain viable and metabolically active. The performance is compared to S. oneidensis suspension cultures and "natural" biofilms. While lower than with the suspension cultures, the power output from the fuel cells with the artificial biofilms is higher than with the natural one. Handling, reproducibility, and stability are also better. Artificial biofilms can therefore contribute to resolving fundamental issues of design, scale up, and monosepsis in biofuel cell technology.

High‐Temperature Spray‐Dried Polymer/Bacteria Microparticles for Electrospinning of Composite Nonwovens

“…Processing of living bacteria as functional units in polymer systems such as particles, microfibers, and nanofibers is important for the exploitation of their unique functions, for example, in waste water decontamination, metal sequestration, bioremediation production of chemicals and energy. However, the harsh conditions of standard polymer processing, like melt extrusion and film casting or fiber spinning from organic solvents, do not match the sensitivity of bacteria.…”

“…However, hydrophobic water‐resistant polymers are required for numerous applications, for example, in textiles, agriculture, microbial fuel cells, or water purification. Previously, we reported on the encapsulation of living M. luteus , E. coli , and Shewanella oneidensis MR‐1 in hydrophilic polymers (e.g., poly(ethylene oxide) [PEO], poly(vinyl alcohol) [PVA]) by electrospinning to polymer mesofibers, by wet‐spinning to polymer microfibers, and by dispersion‐based polymer microparticles . These bacteria‐loaded polymer systems were coated with hydrophobic polymer shells (e.g., poly(methyl methacrylate) [PMMA], poly(p‐xylylene) [PPX]) to prevent the uncontrolled release of the bacteria to the environment.…”

Preparation of Biocomposite Microfibers Ready for Processing into Biologically Active Textile Fabrics for Bioremediation

“…A direct comparison with the hand‐spun fibers was not possible here, as these fibers would have dissolved under assay conditions (aqueous environment). Previously, however, hand‐spun fibers stabilized with a PPX coating had been investigated . Due to the coating (thickness 1 µm), these microfibers had a diameter of 199 ± 16 µm.…”

“…Previously, however, handspun fibers stabilized with a PPX coating had been investigated. [9] Due to the coating (thickness 1 µm), these microfibers had a diameter of 199 ± 16 µm. In these fibers, dead bacteria were also found close to the surface directly after spinning, but after some days in culture, live bacteria had resettled these areas.…”

“…We have recently introduced the concept of the “artificial biofilm” as a fundamentally new approach to integrating single species biofilms into technical processes . Artificial biofilms are defined as biocomposites where specific microorganisms are embedded in a synthetic hydrogel matrix of tunable properties.…”