Kinetic exploration of intracellular nitrate storage in marine microalgae

In this study, a recently developed model accounting for intracellular nitrate storage kinetics was thoroughly studied to understand and compare the storage capacity of Phaeodactylum tricornutum and Amphora coffeaeformis. In the first stage the identifiability of the biokinetic parameters was examined. Next, the kinetic model was calibrated for both microalgal species based on experimental observations during batch growth experiments. Two kinetic parameters were calibrated, namely the maximum specific growth rate [Formula: see text] and the nitrate storage rate ([Formula: see text]). A significant difference was observed for the nitrate storage rate between both species. For P. tricornutum, the nitrate storage rate was much higher ([Formula: see text] = 0.036 m³ g^-1 DW d^-1) compared to A. coffeaeformis ([Formula: see text] = 0.0004 m³ g^-1 DW d^-1). This suggests that P. tricornutum has a more efficient nitrate uptake ability and intracellular nitrate storage capacity and also indicates the need for determination of [Formula: see text] in order to quantify nitrate storage.