Chitosan has proved to be highly effective for dewatering of cultures
of the microalga C. sorokiniana, with flocculation efficiency
reaching over 99% at pH 6 when using a dosage of 10 mg chitosan
per gram algal biomass. By reducing the volume by 20–50 folds,
flocculation process saves both energy and time for downstream
dewatering processes. However, current commercial prices for
chitosan are 20 USD/kg. The cost of the flocculant would therefore
be 200 USD per tonne of algae. It is clear, that this price
needs to fall significantly and the flocculation process further refined
to make it commercially viable.