Microbial Pigments: Post-Lab Reflection


One bacteria strain that I chose was Escherichia coli (E.coli) which produced a blue color. The second strain I chose was Serratia marcescens, which produced a red color. I also used a third bacteria strain to create a pink/cantaloupe color, however, I realized afterward that it required a higher temperature, so it did not appear. Certain genotypes had more or less resistance to antibiotics in the Petri dishes, so the environment restricted the phenotype result. The fact that certain strains had restrictions on temperature requirements for the environment also restricted the ability to mix colors within one piece. With this, I considered temperatures and only used bacterial strains that had the same temperature requirements for their environments. I expected all of my colors to appear as I organized them in accordance to temperature requirements.


For my canvas, I used the third Petri dish, which had LB (Lysogeny Broth), Ampicillin, and X Gal antibiotics. When I used the E.coli bacteria, the X Gal in the dish metabolized, turning blue. The Serratia also reacted with the growth media to form a distinctive red.


For my application, I used a mix of brushes and picks. I wanted thicker lines and shapes with the brushes and interesting patterns with picks. The application with the picks formed distinctive harsh lines, whereas the brushes formed solid shapes or dotted lines. I dipped my tool back into the bacteria dish several times to ensure a solid amount of pigment, assuming the more, the darker. I didn’t know what’d happen with the mix of the two. I assumed they wouldn’t affect one another. When they mixed, a slight gradation occurred in a few places which was quite visually interesting.


I am wondering what the range of possibilities of colors is with this method of pigmentation! Next time, I would try more interesting imagery, such as distinctive shapes or patterns. Bacteria grows in unpredictable ways, so the shapes that I created were different than the result. Due to this, I would say that abstract images or patterns work better than defined shapes. Bacterial paint meshes well with long life design as it is both a sustainable medium as well as an interesting one as it develops and changes over time.

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