In this work, the mild disintegration of the microalgae Chlorella vulgaris for the release of intracellular products has been studied. By means of bead milling the microalgae suspensions were successfully disintegrated at different biomass concentrations (25-145 g(DW) kg(-1)) over a range of agitator speeds (6-12 m s(-1)). In all cases over 97% of cell disintegration was achieved resulting in a release of water soluble proteins. A clear optimum rate of disintegration and protein release was observed at an agitator speed of 9-10 m s(-1) regardless of the biomass concentration. Selective extraction of water soluble proteins was observed as proteins released sooner than cell disintegration took place. Proteins could be released at 85% lower energy input than for cell disintegration resulting in specific energy consumptions well below 2.5 kWh kg(DW)(.)(1) (C) 2014 Elsevier Ltd. All rights reserved.