Cellometer auto x4 cell counter

The cell density of N. gaditana was determined using a Cellometer Auto X4 Cell Counter (Nexcelom Bioscience, USA). Samples were injected into a cell counting chamber with 20 μL volume each and measured in duplicate.
For measurement of the dry cell weight, cellulose nitrate membrane filters with a 0.45 μm pore size (Whatman, USA) were pre-dried in an oven at 80 °C. Suspensions of N. gaditana were passed through the filters using a vacuum pump, and then the filters were dried at 80 °C overnight. The dry cell weight was determined as follows: $$\text{Dry cell weight}=\frac{\left(\text{weight after filtration}\right)-(\text{weight before filtration})}{\text{volume of filtration}}$$ Specific growth rate (μ) was calculated as follows: $$\mu =\frac{ln{X}_2-ln{X}_1}{t_2-t_1}$$ where t is time and X_i is the dry cell weight of N. gaditana at time t_i.

Algae cell concentrations were calculated by pipetting a 20 μL sample of each culture onto a Cellometer counting chamber (Nexcelom Bioscience, Lawrence, MA, USA) and analyzed using a Cellometer Auto X4 Cell Counter (Nexcelom Bioscience, Lawrence, MA, USA).

Cell growth was determined by the cell density and dry cell weight (DCW). Cell density was measured using a Cellometer Auto X4 Cell Counter (Nexcelom Bioscience, USA). The DCW was determined by filtering the cells through a GF/C filter paper (47 mm; Whatman, UK), washing the filters with deionized water, drying them overnight at 105°C, and weighing them on a fine scale.
The concentration of nitrate (NO₃^-) in the medium was determined by an ion chromatograph (881 Compact IC Pro; Switzerland) with a Metrosep A Supp5 150 column for anions. The concentration of glucose was determined by a high-performance liquid chromatograph (Dionex Ultimate 3000; ThermoFisher Scientific) with an Aminex HPX-87H column.