Lack of high-density algal photobioreactors (PBR) has been a limitation in exploiting the biotechnological potential of algae.
Recent developments of highly efficient light-emitting diodes (LED using gallium aluminum arsenide chips) have made the development of a small LED basedPBR possible.
We have calculated theoretical values of gas mass transfer requirements and light-intensity
requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source.
A prototype PBR has been designed based on these calculations.
A cell concentration of more than 2 xlo9 cells/mL (more than 6.6% v/v), cell doubling times as
low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/L culture/h were achieved using on-line ultrafiltration to periodically provide fresh medium.