Cationically functionalized dextrin polymer as an efficient flocculant for harvesting microalgae

The present study sets out to the development of cationic graft copolymer, dextrin -g-PMETAC through grafting of 2-methacryloyloxyethyl trimethyl ammonium chloride (METAC) on to the dextrin polymer. Flocculation efficiency of this graft cationic copolymer was studied towards the biomass harvesting efficiency of three indigenous microalgal strains viz, Scenedesmus sp. CBIIT(ISM), Micractinium sp. NCS2 and Chlorella sp. NCQ. The results demonstrated that the synthesized copolymer was very effective in microalgal dewatering. The biomass harvesting efficiency of the dextrin-g-PMETAC for Scenedesmus sp. CBIIT(ISM), Micractinium sp. NCS2 and Chlorella sp. NCQ was 98.87 +/- 0.17 %, 98.19 +/- 0.22 % and 97.56 +/- 0.28 % at optimized dosage of flocculant 25 ppm 35 ppm and 45 ppm respectively. Comparative study of biomass composition of polymer induced flocculated biomass and centrifuged biomass in terms of proteins, carbohydrates, lipids, and residual ash content indicated that the biomass harvesting through dextrin-g-PMETAC does not affect the characteristics of microalgal biomass. Based on the obtained results, dextrin-g-PMETAC could be considered as an efficient polymeric flocculant towards the harvesting of microalgae. (C) 2020 Published by Elsevier Ltd.