Harvesting Euglena fracilis cells with a nontoxic flocculant

Abstract

Practical criteria for the usefulness of an algal separation process for laboratory routine are effectiveness and time consumption. We tested the feasibility of a flocculation procedure for harvesting a large volume of Euglena gracilis culture. This procedure turned out to be a technically viable system for avoiding tedious centrifugation and preserving Euglena flagellar apparatus integrity. Euglena cultures were treated with chitosan, a byproduct derived from chitin, the major component of the exoskeleton of crustaceans. Since chitosan carries a positive chrge, it functions as a polycationic coagulating agent by adsorbing onto particles in suspension and by bridging into agglomerates or flocs. A 96–98% reduction in the number of suspended cells was obtained in the cultures with 200 mg/l of chitosan at pH 7.5.