Enhancing the microalgae Nannochloropsis sp. harvesting by chitosan-based flocculation-sedimentation for biofuel production

Microalgae is attractive biomass to produce biofuels due to the depletion of fossil fuel existence. However, one of the problems in its application is in the harvesting step, which challenges more technologically and economically efficient. To address this challenge, flocculation-sedimentation is proposed as a harvesting method of microalgae from its cultivation medium. In this paper, flocculation-sedimentation of microalgae Nannochloropsis sp. was studied using chitosan and nano-chitosan flocculant. The effects of both flocculant dosage and sedimentation time of Nannochloropsis sp. flocculation-sedimentation were investigated. As a result, the optimum biomass recoveries for chitosan and nano-chitosan flocculation-sedimentation were 97.23% and 98.44%, respectively, obtained at 0.002 g/L of dosage and 10 minutes of sedimentation time. Furthermore, the flocculation-sedimentation using nano-chitosan was more effective than chitosan for enhancing the microalgae Nannochloropsis sp. harvesting.