We have seen plastic eating bacteria, bioplastic producing bacteria, brick-growing bacteria… Needless to say, bacteria can be very useful in the production (or destruction) of materials, and now paint-growing bacteria can be added to the list. A team from the University of Cambridge and a Dutch company called Hoekmine BV have outlined how we could grow organic paints and coatings out of vibrantly coloured bacteria colonies.

In nature, you can find materials with metallic shimmers, for instance peacock feathers and butterflies. These colours aren’t produced by pigmentation, but rather tiny structures that scatter light. These structural colours are difficult to reproduce, but the research by the University of Cambridge and Hoekmine is a step in the right direction.

The bacteria the researchers used are called the flavobacteria, and colonies of them appear as bright metallic colours, thanks to the mircoscopic internal structure. These structures, like the ones in peacock feathers, reflect the light at different wavelengths, and create in our eyes a certain colour.

The natural colour of the colony is a metallic green. The researchers decided to map the genes responsible for the structural colouration in the bacteria, to understand how nanostructures are engineered in nature. They engineered the flavobacteria with specific mutations, such as the size of the bacteria and how well they could move. These tweaks change the colour the colony appears to be, and the researchers were able to make virtually any colour in the visible spectrum.

According to the researchers, the engineered bacterial colonies could be used to grow organic, biodegradable and non-toxic paints and coatings in any colour.

Photo: University of Cambridge