Pseudomonad cake


We had two high school interning with us this summer, A and B. In the month they were here these two young ladies screened ~3500 transposon mutants and identified several with the phenotype of interest. Needless to say, we’ve been very happy to have them with us and to thank them for their time, I made a cake. WOOO CAKE!


Why this cake? Our lab uses Pseudomonas aeruginosa as a model organism which makes it a pretty good candidate for cakification. I also expected that it would be very easy because Pseudomonas are rod-shaped bacteria.  As a rod shaped cake roughly equates to a cake baked in a sandwich loaf pan with the corners shaved off, this should result in a cake that requires minimal post-baking sculpting.  I thought about making a jelly roll and shaping the edges, but I was afraid I’d lose structural integrity.

Anyway, now that I had a shape, I needed to decide what type of cake batter to make.  Pound cakes are delicious, incredibly fatty and dense, and are often made in loaf pans.  Therefore, pound cake.

P. aeruginosa make a greeny-blue pigment, so I needed to ice the cake in that color.  Since I had some rolled buttercream leftover from the pie chart gut enterotype cookies, I could tint it the right color and try to cover the cake with it. I read that it was difficult to cover a cake in rolled buttercream, but I read that it was hard on the Intarwebs, where I regularly find people who don’t seem to be able to differentiate between commonly used English homophones. Therefore, pound cake covered in rolled buttercream.

Although P. aeruginosa have pili and polar flagella, I decided to nix the pili because I had no viable ideas on how to go about making them. Maybe spun sugar?  I tried to make spun sugar once.  Bad news (burn) bears. The flagellum I decided to sculpt out of the rolled buttercream

Materials and Methods


The cake was assembled and baked as previously described, except a loaf pan was used in place of a tube pan. Excess batter was baked in another loaf pan for personal consumption.


Frosting is necessary to crumb coat the cake and allow the rolled buttercream to adhere. To make the frosting, ~0.5 c honey was whipped into 1 container of Betty Crocker Whipped Vanilla Frosting.

Rolled buttercream

Rolled buttercream was assembled as previously described. Blue and green food coloring were kneaded into rolled buttercream to approximate the color of P. aeruginosa.


Cake was cooled in the freezer.  The top was leveled, the edges were straightened, the cake halved horizontally with a large cake knife.  Approximately 1 cm of frosting was spread on the bottom layer and the top layer of cake was replaced.  (Note: the entire cake wound up inverted due to nearly-catastrophic investigator error.)

The cake was sculpted with a small kitchen knife to resemble a bacillus. A thin crumb coat of frosting was applied to the cake and the frosted cake was cooled in the refrigerator.

Rolled buttercream was rolled using a rolling pin to ~0.5 cm on a sheet of parchment paper.

The buttercream was transfered to the cake and carefully smoothed with a small cake spatula.

Excess was trimmed off with a knife. Holes and tears were repaired by patching with excess rolled buttercream and smoothed with a small metal cake spatula dipped in hot water.

The flagella was sculpted out of rolled buttercream.

Results and Discussions

Meh. Well, it sort of looks like a pseudomonad. I didn’t round the ends as much as I should have. It also looks a little plain. I think something for the pili would have helped. And it turnes out rolled buttercream is hard to work with. Sorry people I dismissed on the Internet! The next time I decide to make a cake, I will try to start it earlier than the night beforehand. I will also give marshmallow fondant a shot in the future. Thanks to O’s lovely lady L and the lab’s Christmas white elephant exchange, our household still has a metric shit ton (1000 butt loads, not to be confused with the short shit ton, 907 butt loads, or the long shit ton, 1016 butt loads) of marhsmallows.  I’ve been using them to make these, but there are still sooo many mooooore.

2 thoughts on “Pseudomonad cake

  1. This cake was so delicious! It didn’t taste like bacteria at all. 🙂 I had so much fun working in the lab this summer, and I’m definitely going to miss it. Thanks for all your help! -B

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