Centrifugation is a method of separating algae from the medium by using a centrifuge to cause the algae to settle to the bottom of a flask or tank. Centrifugation and drying are currently considered too expensive for personal use, though may prove useful on a commercial and industrial scale.
Centrifuge:
A Centrifuge is a useful device for both biolipid
extraction from algae and chemical separation in biodiesel. Coupled
with a homogenizer, one may be able to separate biolipids and other
useful materials from algae.
A centrifuge is a piece of equipment, generally driven by a motor, that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis. The centrifuge works using the sedimentation principle, where the centripetal acceleration is used to evenly distribute substances (usually present in a solution for small scale applications) of greater and lesser density.
Continuous-flow centrifugation with the classical Foerst rotor is widely used method. This method is reasonably efficient, but sensitive algal cells may be damaged by pelleting against the rotor wall and the method is essentially unselective ; all particles with a sedimentation rate above some limiting value will be collected.
The variant on zonal centrifugation known as continuous sample-flow with isopycnic banding offers a number of theoretical advantages in the concentration(and simultaneous purification)of particles:large capacity, more efficient recovery at substantially lower speeds than are required for conventional continuous-flow centrifugation, and avoidance of pelleting. Plankton including algae, have been collected in sucrose gradients in the zonal rotors, but we do not know either the efficiency of recovery or the integrity of the recovered algae.
See the following pages on Algae Harvesting:
