Base on the results from Sections 3.1 to 3.5, preliminary
optimized parameters to grow immobilized microalgae were determined.
However, uncontrollable free cells culture was still detected
on day-10 due to beads leakage and availability of nutrients
sources at the outer boundary of immobilized microalgae beads.
Therefore, a strategy to co-immobilize with nutrients into the
microalgae beads is suggested to limit the nutrients available for
free cells. Fig. 7 shows the effect of co-immobilized nutrients at
different concentration. From the figure, microalgae beads with
50 mL of co-immobilized nutrients grow in an exceptionally fast
rate, in which their growth reached stationary phase on day-5.