Firstly, the effect of initial inoculums spores and initial pH of
medium on fungi–algae pellets formation was studied. Spores
inoculums of different sizes were added to culture media. It was
shown that the inoculums sizes ranged from 1.1 102 to
1.2 105 spores/mL could help form fungi–algae pellets under
heterotrophic growth mode (Table 2a), suggesting the unique pel
lets-forming property of the isolated fungi species used in this
study. However, it was found that when initial spores inoculums
was 1.2 106 spores/mL, fungi–algae pellets was not observed
even after 7 days cultivation., which is in agreement with reports
by Foster [31], which demonstrated that fungal cell pelletization
occurred when relatively low spores numbers were inoculated initially
[30]. Since the initial spore concentration of 1.1 104 spores/
mL was found suitable for efficient pellets formation in short
growth period in this study, this inoculums size was used in the
subsequent experiments.