During the growth experiments, 3 glass tubes were removed on
days 1, 3, 5 and 7 to serve as triplicates for measuring the nutrient
levels. Culture samples from each tube were first centrifuged at
4000 rpm for 10 min and the supernatant was diluted prior to
analyses. Dissolved concentrations of ammonia nitrogen and phosphorus
(phosphate) were determined using HACH DR 6000 (HACH,
Colorado, USA) spectrophotometer (Salicylate TNT Method 10031
and Phosver 3 Method 8048).