Integrated microbioreactor for culture and analysis of bacteria, algae and yeast.

We introduce a micro-scale bioreactor for automated culture and density analysis of microorganisms. The microbioreactor is powered by digital microfluidics (DMF) and because it is used with bacteria, algae and yeast, we call it the BAY microbioreactor. Previous miniaturized bioreactors have relied on microchannels which often require valves, mixers and complex optical systems. In contrast, the BAY microbioreactor is capable of culturing microorganisms in distinct droplets on a format compatible with conventional bench-top analyzers without the use of valves, mixers or pumps. Bacteria, algae and yeast were grown for up to 5 days with automated semi-continuous mixing and temperature control. Cell densities were determined by measuring absorbances through transparent regions of the devices, and growth profiles were shown to be comparable to those generated in conventional, macro-scale systems. Cell growth and density measurements were integrated in the microbioreactor with a fluorescent viability assay and transformation of bacteria with a fluorescent reporter gene. These results suggest that DMF may be a useful new tool in automated culture and analysis of microorganisms for a wide range of applications.