Effect of an organic fertilizer on growth of blue-green alga Spirulina platensis

In this study, the influence of an agricultural liquid organic fertilizer on growth and biomass composition of Geitler was studied. In the first trial, five concentrations of organic fertilizer were arranged, e.g., 0.1, 0.25, 0.5, 1 and 2 ml/l, in which no other extra nutrients except bicarbonate were used. Maximum dry weight, chlorophyll and specific growth rate were achieved in control group. In the second trial, initial fertilizer levels of the three groups were 0.1 ml/l and all groups contained sodium bicarbonate. One of the groups had 2.5 g/l NaNO3, while the other was supported with 0.1 ml/l fertilizer by two-day intervals to see the effect of nitrogen. In order to understand the effects of phosphate, 0.4 g K2HPO4 was added to the other group as well as 2.5 g NaNO3. Between the experimental groups, the highest chlorophyll value was found in control group as 53.97 mg/l. The chlorophyll value at group II (37.65 mg/l) was lower than the control group. The maximum dry weight and crude protein recorded in control group were 1,330 mg/l and 60.17%, respectively, when compared with 1,256 mg/l and 59.92% in group II. No significant differences were observed in crude protein values of grown in control and group II ( < 0.05). Consequently, it was seen that commercial liquid organic fertilizers may be replaced by Zarrouk's medium except for nitrate, phosphate and bicarbonate in . cultures in order to decrease the production costs.