Evaluation the effects of temperature, magnesium and iron on Arthrospira plantensis growth and biomass production

this study was conducted to investigate the effects of temperature (24 and 30 ˚C), magnesium and iron removal on Arthrospira plantensis growth and biomass in vitro For this purpose two culture media have been used: Zarrouk and Jourdan culture medium. Removal of magnesium and iron were performed in six treatments and two controls with three replications. Temperature experiments were performed in two treatments with three replications for two mentioned media. Optical density of samples was measured daily by a spectrophotometer at 560 nm. In addition, biomass was measured in g/l at two stages (in 7 and 14 days). pH was measured daily. The results showed that in Zarrouk culture medium (control), mg free treatment and mg-fe free treatment have the highest biomass in day 7 (0.88 g/l). In day 7, among all treatments (mg free, fe free, mg-fe free), only mg free treatment showed statistically significant with standard culture medium (Zarrouk), (p<0.05). In day 14, the mg free treatment showed the highest biomass (0.95 g/l), but there was not significant difference between treatments (mg free, fe free, mg-fe free) and standard culture medium (Zarrouk), (p<0.05). In Jourdan culture medium, control and fe free treatment have the highest biomass (0.7 g/l) in day 7; and fe free treatment has the highest biomass (1.27 g/l) in day 14; but there was not significant difference between treatments (mg free, fe free, mg-fe free) and standard culture medium (Jourdan), (p<0.05). Regarding to temperature effects, in Zarrouk and Jourdan media, the highest growth observed at 24˚C and 30˚C, with 2.74 and 2.14 g/l respectively. There was significant difference between treatments (24 and 30˚C), (p<0.05). results indicated A. plantensiscan be cultivated in large scale by removing magnesium and iron from medium by this way, we could reduce the culturing cost of A. plantensis.