A microfluidic photobioreactor array demonstrating high-throughput screening for microalgal oil production

Microalgae are envisioned as a future source of renewable oil. The feasibility of producing high-value biomolecules from microalgae is strongly dependent on developing strains with increased productivity and environmental tolerance, understanding algal gene regulation, and optimizing growth conditions for higher production of target molecules. We present a high-throughput microfluidic microalgal photobioreactor array capable of applying 64 different light conditions to arrays of microscale algal photobioreactors and apply this device to investigate how light conditions influence algal growth and oil production. Using the green colony-forming microalga Botryococcus braunii, the light intensity and light-dark cycle conditions were identified that induced 1.8-fold higher oil accumulation over the typically used culture conditions. Additionally, the studies revealed that the condition under which maximum oil production occurs is significantly different from that of maximum growth. This screening test was accomplished using the developed photobioreactor array at 250 times higher throughput compared to conventional flask-scale photobioreactors.