Eureka, this is yet another post about Brettanomyces and agar plates. Todays post is about the results of streaking a pure Wyeast’s Brettanomyces lambicus culture on Sabouraud agar plates. I first streaked some liquid from the Brett package on a plate and let it incubate for six days.
Fig 1: Wyeast's Brettanomyces lambicus on Sabouraud agar after six days of incubation
There are some bigger circular colonies and smaller ones visible (Fig 1). The bigger ones are circular, off-white, glossy, even and convex. To check if there are two different morphologies (big and small colonies) as seen in Fig 1, I picked a small colony and streaked it on a new plate.
Fig 2: Wyeast's Brettanomyces lambicus on Sabouraud agar after eleven days of incubation
And there is just one kind of colony visible (Fig 2). These colonies are off-white, glossy, more or less even, circular or wavy and convex. So very similar to the bigger ones as seen in Fig 1. Therefore both colonies (big and small in Fig 1) are the same. Some margins of the colonies were not even anymore and had a wavy margin. But this can even be observed in pure Saccharomyces cerevisiae colonies.
To summarize, Brettanomyces lambicus from Wyeast form off-white, glossy colonies on Sabouraud much like Saccharomyces cerevisiae. So no way to differ between Brettanomyces and Saccharomyces. I already observed the same with the colonies from Brettanomyces bruxellensis. And even the colonies from both Brettanomyces (B. bruxellensis and B. lambicus) look very similar as well. Similar observations were made by Jason from sciencebrewer. This concludes, Sabouraud agar is really not useful to differ between Saccharomyces and Brettanomyces. But this was not the goal of these plates in the first place. I just wanted to see how the different Brettanomyces look like on the plates. Further experiments are necessary to find an agar to differ between Brettanomyces and Saccharomyces. Nevertheless, for the upcoming experiments, it is useful to know how the colonies could look like in the first place.
I am still planning my next experiments concerning Brettanomyces so it could take a while until further results are available. But there will be other posts about Brettanomyces in the future. Some of them will focus on the morphology, some about techniques how to differ between them such as using PCR, another post will be about the taxonomy of Brettanomyces and other posts will be more about the genetics of Brettanomyces. Basically more about science behind Brettanomyces rather than experimental data. I try to make them as easy to read as possible and hope these posts will be interesting to some of you as well.
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