Painting with Microbes

Lab section: F02

I wanted to see what the difference would be using the same bacteria on all three plates.   I used Enterobactor aerogenes for the sun on each plate, Serratia marcescens was used for the birds on each plate and Chromobacterium violaceum was used for the oceans.   Both the Eosin Methylene Blue (EMB) and MacConkey plate select for Gram-negative organisms, while the Trypticase soy agar (TSA) plate is a general growth media.   EMB and MacConkey plates are both differential for lactose fermentation.

All three of the bacteria I used are Gram-negative. As seen from the McConkey plate, S. marcescens, E. aerogenes, and C. violaceum all show lactose fermentation as the entire plate is almost clear.   From the EMB plate we can see that lactose acid has been released during fermentation from the green sheen of   C. violaceum and the dark colors of the other two.

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