It is understood that some bacteria can produce their own electricity, which may make them useful in batteries and fuel cells. But so far, such attempts have been inefficient and inflexible. Now, researchers at the Karlsruhe Institute of Technology (KIT) have created a “biomix” system built around hydrogels that support microbes and efficiently collect their energy.
The core bacteria of this system are called “external organisms”. This family of microbes can produce electrons that pass through the outer membrane and then leave the cells. If we can capture these electrons, the external bacteria can basically help build a living battery, but they need conductive materials to divert electrons to the electrodes, but most of these materials are not suitable for bacteria to survive, and those that make the microbial family more comfortable to survive are not efficient conductors.
For the new study, the researchers developed their own material stoain to get the best results for both. It is first and foremost a hydrogel, a hydrogel consisting of carbon nanotubes and silicon dioxide nanoparticles that conduct electricity. These are fixed together with strands of DNA. The external bacteria are then added to the medium containing nutrients to keep them alive.
The team found that the bacteria grew well on the material and were able to penetrate deep into the pores of hydrogels. Hydrogels also do well in conducting electricity. The researchers also built a method to turn off the battery. When no electricity is needed, an enzyme can be added to cut off the DNA strands and cause the material to collapse. The researchers say some of the properties of the material can be changed by adjusting the formula, especially the size and sequence of the DNA strands, thereby changing some of the properties of the material.