Chitosan resulted to be an effective natural flocculant for
microalgae biomass harvesting obtaining flocculation efficiencies
up to 92%. It was found that chitosan concentration mainly determined
flocculation activity whereas agitation speed had little effect
on it when pH adjustment was carried out. The highest flocculation
efficiency (92%) was obtained at a concentration of 214 mg L−1 and
an agitation speed of 131 rpm.
Further research is needed in order to evaluate the influence
of other factors (such as, initial pH and biomass concentration)
for chitosan flocculation and, therefore, to optimize the microalgal
harvesting method.