titration was performed to more specifically identify
ion-binding groups, compared to FTIR spectroscopy, and
to determine their concentrations onto microalgal cell
wall. Measurements were conducted with both microalgal
biomasses, according to the method elaborated in previous
works [20, 24]. Biomass samples of 0.2 g suspended in deionized
water (200mL) were titrated with 0.1M NaOH till pH
11.5 and reversely with 0.1M HCl till pH 2.5, both solutions
were standardized (POCh S.A., Gliwice, Poland). The pH
change was monitored after single dose of titrant, when the
record stabilization was achieved. As control (blank) sample,
deionized water was used. Before each titration test, the water
was purged of dissolved CO2 by 3-hour bubbling with argon.