C. reinhardtii P. patens
proton exchange capacity (mmol*g-1) 0.39 0.44
maximum Nd3+ sorption capacity (mmol*g-1) 0.26 0.74
pKa1 4.4 4.0
pKa2 7.5 5.4
pKa3 8.9 6.8
pKa4 11.0 9.5
Table 1: Chemical properties of biomass binding sites, generated by titration of dry biomass.