What is a Bioreactor?

A bioreactor is a vessel that provides an optimised environment for growing cells, microorganisms, and microbial cultures. In its simplest form, it could just be a jar, but the term 'bioreactor' commonly describes more complex setups in which the environment can be controlled and automated. Bioreactors are typically used in the development of pharmaceuticals, as well as in the food sciences, medical sciences, and many other chemistry- and biology-adjacent sectors.

The Pioreactor is small: the working volume is just 20ml. You definitely aren't going to grow enough algae for your fuel cell, or to create a decent food supply. For experiments and research, however, it offers a wide range of environmental controls straight out of the box. It's capable of automating experiments over long periods of time and can also log data about the experiments you schedule it to perform.

How to Build the Pioreactor

Building the Pioreactor is pretty straightforward — all you need is a Pioreactor kit. LabCrafter supplies open-sourced science equipment, including the OpenFlexure microscope kits and current models of the Pioreactor, as well as numerous add-on accessories and expansions.

You can build a Pioreactor using any choice of Raspberry Pi model, whether that's a Model A, a Model B, or any of the Zero-series boards. You begin by attaching a base to your Raspberry Pi, followed by some standoffs, before finally fitting the Pioreactor HAT onto your Raspberry Pi's GPIO header. The instructions are online and they are excellent.

Assembly continues with the 'wetware' section: the main chamber of the Pioreactor that holds the glass vial containing your experiment. You fit the supplied O-rings to the base of the vial chamber and the chamber wall, then insert the small heater element into the chamber. The clearances for various parts of the mechanism are quite accurate, so you need to double-check that you are assembling it using the correct bolts.

There are numerous holes in the side of the chamber wall, allowing for the addition of an optical system later on. The included optical system consists of an infrared (IR) LED and two photodiodes in the same 5mm LED form factor. These are fitted later in the build, allowing you to automatically measure the optical density of your experiment.

Installing the Software

Once you have all of the hardware assembled, it's time to grab a microSD card and install the software that runs your Pioreactor. This is neatly achieved using the custom Raspberry Pi OS image supplied by the Pioreactor team. With the latest version of the official Raspberry Pi Imager application, installation is easy.

On the App Options page, you can edit the 'content repository' tab and add the custom URL for the Pioreactor OS image. If you then reboot Imager, you should be able to select your Raspberry Pi device and see the Pioreactor OS available to install to your microSD card.

Booting Your Pioreactor

Once the software is installed, you can boot your Pioreactor by connecting a power supply. After a few minutes you should see a blue LED blinking on the Pioreactor HAT. Then, on a laptop connected to the same Wi-Fi network, open a web browser and navigate to http://pioreactor.local. A pop-up window will ask you to confirm which Pioreactor version you have; after selecting this, a dashboard for your Pioreactor will appear.

Experimenting

A good first experiment is described on the AMYBO website. You are going to grow some yeast using a yeast extract peptone dextrose (YPD) broth, which is a common growth medium used in all manner of microbiological cultivations. The experiment basically grows yeast in the YPD broth, stirring and warming the mixture while taking periodic optical density measurements to track its growth.

The Pioreactor is a capable device in its standalone form, but there are lots of add-ons and modifications available or in development within the community. For example, some expanded systems can push CO₂ through the liquid in the chamber, which can be used to remove other volatile compounds from a sample. The community continues to build and develop these complex tools for everyone.

TL;DR

  • Pioreactor is a Raspberry Pi-powered automated bioreactor for scientific experiments and research on your desk
  • Kit assembly is straightforward with online instructions; works with any Raspberry Pi model
  • Web-based dashboard makes it easy to run experiments, control stirring, temperature, and optical density measurements
  • Active community developing advanced features like CO₂ sparging and in-chamber electrolysis
  • Affordable tool for professional, amateur, and hobbyist biologists and chemists

Source: Raspberry Pi Blog