. Biomass preparation
A 2% solution of Alginic acid sodium salt from brown algae (Sigma)
was dripped into 0.05 mol/L CaCl2 solution with the gentle magnetic
stirring to form calcium alginate beads. In order to stabilize the beads,
the Ca-alginate beads in CaCl2 solution would be stored in a fridge at
4 °C for 24 h. Then the beads were filtered and washed several times
with deionized water to remove the excess CaCl2 solution. Finally, the
beads were dried in an oven at 50 °C for 24 h to form the dried
Ca-alginate beads which would be used as biomass materials in the
experiments. The dried beads would be stored in a clean and dry bottle
for further experiments.