These water lilies weren’t painted with a brush – they were created by bacteria. The different colors and the fine structures are created by applying different types of microbes to the nutrient medium. With this living work of art, a German student won first prize in the international “Agar Art Contest” of the American Society for Microbiology. A total of 300 works of art from 31 countries were submitted for the competition.
When bacteria are placed on a suitable nutrient medium, they multiply quickly and typically form round or thread-like colonies. Depending on the type and nature of the nutrient medium – pH range, salt and sugar content and temperature – these microbial colonies can develop different colors and shapes. This is exactly what those taking part in the Agar Art Contest use to create living works of art in the Petri dishes through a targeted selection of species and media.
How pictures are created from microorganisms
This water lily painting is by Sonja Borndörfer from the Weihenstephan-Triesdorf University of Applied Sciences (HSWT). The student created her work “Microlilies” with the help of a “ink box” of microbes that had been cultivated at the university for a long time – a lengthy and difficult task. In the first step, she had to try different combinations of bacterial species and culture media in order to achieve the desired color and structure.
Then the microorganisms are applied to the agar base with a tiny loop according to the picture template. “You have to disinfect the loop every now and then and be very careful not to mix two different strains of microbes. If that happens, the picture becomes unusable, ”reports Borndörfer. In addition: While you are applying the microorganisms, you cannot see anything of the picture, because their number is still too small for their color to be visible.
“Only when the organisms in the Petri dish have multiplied under suitable growth conditions and have reached a certain number, the created image becomes visible,” explains Borndörfer. At this point the growth process is stopped by placing the petri dish in the refrigerator. “I took part out of pure interest to try something new and suddenly my picture is published on the other side of the Atlantic,” says the microbiology student.
Colors are also medically relevant
The effort has paid off: Borndörfer’s water lily picture received first place in the “Professional” category of the international “Agar Art” competition. Since 2015, this competition has been honoring works of art in five categories that were created with living microorganisms on an agar base. The aim is to bring the world of microorganisms in all their diversity and beauty closer to the public.
The play of colors with the microbes is not just pure art or gimmick: The fact that microorganisms take on certain colors on certain nutrient media is used, for example, to identify germs in the medical and food sectors. For example, cystitis pathogens and other pathogenic germs grow in blue on certain nutrient media, which can help with the diagnosis.
Source: Weihenstephan-Triesdorf University of Applied Sciences