Production and physicochemical characterization of chitosan for the harvesting of wild microalgae consortia

•The chitosan obtained shows physicochemical properties similar to commercials.•The low molecular chitosan for harvesting microalgae shows better results than aluminum sulfate.•The use chitosan for harvesting microalgae reduces the process costs. The use of chitosan to harvest microalgae is a strategic step that seeks to reach an economically competitive price to recover lipids, proteins, and pigments. The aim of the present work was to design low-molecular-weight chitosan from shrimp shells and its physicochemical characterization, to be used for the harvesting of wild microalgae consortia. The chitosan was obtained by chemical deacetylation of shrimp shells, and physicochemical characterization was made using the instrumental methods DSC, TGA, X-ray, FTIR, and SEM. The harvesting of wild microalgae consortia was performed by the jar test method. The obtained chitosan had a low molecular weight (169 KDa), a deacetylation degree of 83 %, a decomposition temperature (TD) of 280 °C, and a crystallinity of 38.2 %. The microalgae genera found in the consortium were Scenedesmus sp., Chlorella sp., Schroderia sp., and Chlamydomonas sp. The microalgae removal efficiency of the chitosan was 99.2 % with 20 mg L−1.