Current Work: Kombucha

By way of apology for the prior wall-of-text post, I'll include here some information on what I am currently doing in the lab. Nothing's ready or completed, but I figure some insight into my workings and goals at present might be nice.

In keeping with my general intention to make it as easy as possible for amateurs to get into Biotech, I would like to offer a number of pretty easy starter cultures that people can get started with while not requiring too much early investment in equipment.

It's no secret that I love Bacillus subtilis. I've designed a plasmid for use by amateurs, which ultimately I'm hoping to sell as part of a beginner's kit; Your First GMO. Until the plasmid is tested fully though, I'm working on an alternate platform.

Ever heard of “Kombucha", a form of fermented tea? Few have in Ireland, except perhaps as an alternative soft drink available in health stores and Wagamamas. However, Kombucha must surely have a deeper legacy than even its currently recorded history would suggest.

A marraige of alcohol-producing yeasts and alcohol-consuming bacteria, Kombucha is well-known by its brewers to produce a mushroom-like pellicle upon the surface of a fermenting culture. This pellicle is composed of exceptionally high-quality cellulose and whatever microbes become trapped in it, particularly the one responsible for its production, Gluconacetobacter xylinus.

G.xylinus has been studied for its prolific production of cellulose (in addition to acetic acid) for a long time, but the strain found in Kombucha produces a particularly exceptional amount and quality of cellulose, suggesting that selection by generations of homebrewers may have created a domesticated substrain. The species has had its genome sequenced, and has been subjected to several key genetic manipulations proving that it can be engineered.

Most relevantly to beginner biotechnologists, the low pH of fermenting Kombucha (due to G.xylinus) makes it very inhospitable to contaminating bacteria. When coupled with the low residual alcohol of a co-cultured yeast (about 1% or less), Kombucha can be very resilient against contaminants, requiring little or no equipment to grow and maintain. I've already satisfied myself (due to gross negligence) that Kombucha is stable over prolonged storage at room termperature, reviving almost immediately. Finally, the pancake means you can handle the culture easily with clean hands, if forceps aren't available. This makes Kombucha an ideal beginner's culture, even moreso than ‘normal’ homebrewing yeasts.

It's not enough for me to supply Kombucha, though; you can get it on Ebay anyway, and it's not ideal for DIYbio uses as it comes in traditional cultures. In order for Kombucha to be of use, it must be better characterised than “seven or so species of yeast and bacteria”. Ideally in science you reduce the number of unknowns to as low a manageable level as you can; that way, you have to apply less effort to get useful answers. This means a Kombucha with fewer, better understood species would be far preferable for science if not for brewing.

So, what you'd find if you came into the lab tomorrow would be a collection of partially separated cultures derived from my own Kombucha culture, purchased over a year ago on Ebay. I'm trying to isolate just the G.xylinus strain from my Kombucha, which I'm planning then to recombine with Baker's Yeast, preferably a lab strain of Yeast, to form a “Lab Strain” of Kombucha. This strain, once ready, will be sold as a beginner's brewing kit to offer people a soft landing into the world of microbiology, while retaining the potential for future experimentation and work (genetic manipulation of yeast and/or G.xylinus should be possible, requiring only a good DNA vector).

So that's what I'm doing right now, playing with Kombucha and applying for permission to finish my work with Bacillus subtilis. If you have any thoughts to share, please do!

 Share, if you like. Fediverse sharing is preferred, though.