In early 2014 I was asked if I might be interested in developing some designs for a home/school-targeted bioreactor product. I was!
Side view layout sketch for the semi-automated bioreactor concept. It included a transparent water-jacket insulated chamber with additional controlled heating for the primary reactor vessel.
First prototype on display at Maker Faire Bay Area, 2014
The initial prototype, based on above sketches, was created in a matter of weeks, but there were refinements to make...
The next prototype, started in March 2015, was based on the concept of a water cooler which served to continuously ferment a bacterial culture. This prototype and the next were partially funded as part of IndieBio’s first class.
The vessel was a 6 gallon glass carboy. After the base was made, I drilled some ports in the top (bottom) of the carboy to allow liquids to circulate & agitate the culture in a pump-over technique. Shown above are the fill/feed/airlock port in the center, and the recirculation port off to the side.
The components are all off-the-shelf plumbing fittings. I chose a diaphragm pump to circulate the liquids because they are self-priming and less-detrimental to microbial populations when compared to the shear-forces generated in centrifugal pumps. 3-way valves controlled flow & filling (manually) and a solenoid valve controlled the dispensing of the liquid culture.
The prototype was tested for leaks, washed, then a starter culture of EM-1 was added along with filtered water and blackstrap molasses. The pump's outlet hose was angled in such a way that the pump-over action caused a vortex to form in the liquid, fully mixing the contents.
With the addition of an electric heater belt, the culture was off and running!
With a proof-of-concept model out of the way, we began designing a fully-featured prototype.
Here is the result of some MIG welding (before grinding) at TechShop Mid-Peninsula.
There were a LOT of small components specially designed for this prototype, many of them cut out of acrylic plastic sheets.
The end result of a few intense weeks of fabrication was a machine which could continuously 'brew' a liquid culture of aerobic or anaerobic bacteria and/or fungi. Additions of solid &/or liquid inputs and mechanical agitation (via pump-over or impeller) could be automatically performed based on real-time monitoring of pH, EC, dissolved oxygen, and liquid temperature. Colored lights were included to both act as an indicator of the state of the machine, and also provide light energy to the culture as needed. Liquid output dispensing was again controlled by solenoid valve.
First test of the agitator/mixer creating a vortex in water.