Increasing the initial sucrose concentration further did not enhance the growth of this strain. The growth rate slightly decreased when the initial sucrose concentration was increased to
1 g/L. This could have been an effect of substrate inhibition (Chen and Johns, 1995). Chen (1996) and Chen and Johns (1994) have both indicated that, compared with bacteria and yeasts, microalgae
can tolerate only relatively low substrate concentrations (Chen, 1996; Chen and Johns, 1994).