Study of algal biomass harvesting using cationic guar gum from the natural plant source as flocculant

[Display omitted] ► Cationic guargum (CGG) was synthesized from natural plant source guargum (GG). ► CGG has higher intrinsic viscosity than GG. ► CGG is proved to be better flocculant than GG towards algal biomass harvesting. ► The optimized dosage was 40ppm for Chlorella sp. CB4 and 100ppm for Chlamydomonas sp. CRP7. Microalgae are small in size with negatively charged surface. They are usually stable in suspension culture and hard to flocculate. The present work emphasizes on the synthesis of cationic guar gum (CGG) by the introduction of quaternary amine groups onto the backbone of guar gum (GG) from N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC). The optimal dosage of the synthesized cationic guar gum is used to flocculate two different green algae viz. Chlorella sp. CB4 and Chlamydomonas sp. CRP7.