pH control in a miniaturized bioreactor

Abstract

A miniaturized bioreactor with a volume on the order of 100 [micro]l has been built with the aim of increasing the efficiency of the screening process for various microbial cultures. Unlike larger reactors currently in use, the current miniaturized design lacks a method of pH control. Without pH control, cell growth can be hindered or even stopped altogether when the growing medium becomes too acidic. Using technology already in place to optically measure the pH inside the reactor in conjunction with a valve and a base-filled reservoir, a simple closed-loop (feedback) control system has been developed. The volume of base injected into the reactor must be minimized because the reactor itself is so small. Data is recorded and control signals are outputted by a computer running LabView software. While the control system developed in this thesis shows promise, further development is needed before it can be put to good use.