Biobattery uses spore-forming bacteria in artificial intestinal villi

A team of scientists at Binghamton University has taken an unusual approach to designing a new kind of biobattery that uses spore-forming bacteria to generate bioenergy. The researchers drew inspiration from mechanisms involved in the formation of microorganisms in the human digestive tract. The biobattery could be installed in wastewater pipes to clean wastewater autonomously while generating energy.

Researchers at Binghamton University took inspiration from the colonization processes of microorganisms in the small intestine to create ideal conditions for spore-forming bacteria to generate bioenergy. Intestinal villi, fingerlike projections in the small intestine, play a special role in the proliferation of microorganisms in the digestive tract, the scientists write in the study “Intestinal Villi‐Inspired Living Biobatteries via Habitat‐Engineered Conductive Hydrogel Architectures”, published in Small. Villi have a large surface area, allowing bacteria to colonize and multiply there readily.

The scientists therefore wanted to create artificial villi to grow spore-forming “Bacillus subtilis” bacteria. But earlier approaches using porous materials with large surface areas for better bacterial colonization were not suitable. The porous structures become clogged as biofilms form, hindering the supply of nutrients and the buildup of metabolic products and leading to uneven growth of the biofilm needed. Villi serving as electrodes in the biobattery are intended to avoid this problem. They have a large surface area and short diffusion paths, enabling efficient mass transport. They are also mechanically stretchable, flexible and scalable.

Artificial villi as a battery anode

The researchers recreated the villi using a flexible polymer hydrogel and incorporated inactive bacteria into the structure. The villi serve as the biobattery’s anode. To generate an electrical voltage, they are separated from a cathode made of modified carbon fabric by an ion-exchange membrane.

When a nutrient medium is supplied continuously, the system produces a stable voltage. In experiments, the scientists managed to generate a stable voltage of 0.75 volts for at least 14 hours. That was enough to light LEDs or power tiny body sensors.

The researchers believe the biobattery is suitable for cleaning wastewater autonomously. Installed in wastewater pipes, it could use waste substances in the wastewater as nutrients for the bacteria, which would also generate energy.

The scientists at Binghamton University now plan to optimize biobattery production by developing a scalable, single-step 3D-printing process. They also aim to better reproduce the biological processes of the small intestine in the artificial villi. This should lead to a better understanding of how bacterial cells can maintain their viability.

(olb)