An energy and resource efficient alkaline flocculation and sedimentation process for harvesting of Chromochloris zofingiensis biomass
Journal article, 2020

Harvesting microalgal cultures is often energetically intensive and costly. To improve efficiencies, a two-step harvesting method utilising alkaline flocculation and sedimentation to pre-concentrate cultures can be used prior to centrifugation. When applied to the microalga Chromochloris zofingiensis, high rates of sedimentation (>90%) were found at low concentrations of base (<10 mM), with the addition of magnesium to the media (via NaOH/MgSO4 or Ca(OH)2/Mg(OH)2) to form Mg(OH)2. The process was scaled to 180 L, where sedimentation was as efficient as that achieved at bench scale. Characterisation of the harvested biomass showed comparable composition (following neutralisation of pH) to biomass recovered solely by centrifugation. The alternative two-step processes were assessed for environmental impacts and cost, which indicated that a two-step harvesting generally performs better than centrifugation alone, but that the locally available electricity source is a critical parameter for optimal solution.





Life-cycle assessment


Joshua Mayers

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Andrew R. Landels

Plymouth Marine Laboratory

Rothamsted Research

Michael J. Allen

Plymouth Marine Laboratory

University of Exeter

Eva Albers


Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Bioresource Technology Reports

2589014X (eISSN)

Vol. 9 100358

Upgrading of renewable domestic raw materials to value-added bulk and fine chemicals for a biobased economy: technology development, systems integration and environmental impact assessment (BioBuF)

Formas (213-2013-78), 2013-06-17 -- 2018-12-31.

Region Västra Götaland (RUN612-0806-13), 2013-11-01 -- 2018-10-31.

Subject Categories

Renewable Bioenergy Research

Other Environmental Engineering

Energy Systems



More information

Latest update