RESPONSE OF DIATOM NITZSCHIA PALEA CULTURE TO DIFFERENT CONCENTRATIONS OF NITROGEN, PHOSPHORUS AND SILICON

Abstract

The effect of essential nutrients (nitrogen, phosphorus and silicon) was tested on growth of algae (Bacillariophyceae) Nitzschia palea (Kuetz.) W. Smith under control conditions (temperature 25 ºC and light intensity 260µE/m²/sec). Modified Chu-10 was used as growth medium. The results showed that nitrate was the best for algal growth than other nitrogen sources (urea and ammonia). Four different concentrations of nitrate (15,20,30,40mg/L) as well as control medium which contain 8.7mg/L of nitrate were tested. The highest growth rate (0.55 cell/h) and the lowest doubling time (12.95 h) were recorded in 15mg/L of nitrate. The diatom was cultivated also in four different concentrations of phosphorus (5,10,20,30mg/L) as well as 1.78mg/L of phosphate in control medium. The treatment of 5mg/L phosphate showed highest growth rate (0.57 cell/h) and lowest doubling time (12.75 h). The third essential element (silicon)of the diatom was tested in five concentrations (10,15,25,35,45mg/L) within the control treatment 5.7mg/L. The best for both growth rate (0.83 cell/h) and doubling time (8.72 h) were recorded at 10mg/L. So, new medium was suggested for cultivation of this alga.

Keywords

The effect of essential nutrients, nitrogen, phosphorus and silicon was tested on growth of algae, Bacillariophyceae Nitzschia palea, Kuetz. W. Smith under control conditions, temperature 25 ºC and light intensity 260µE/m²/sec. Modified Chu-10 was used as growth medium. The results showed that nitrate was the best for algal growth than other nitrogen sources, urea and ammonia. Four different concentrations of nitrate, 15, 20, 30, 40mg/L as well as control medium which contain 8.7mg/L of nitrate were tested. The highest growth rate, 0.55 cell/h and the lowest doubling time, 12.95 h were recorded in 15mg/L of nitrate. The diatom was cultivated also in four different concentrations of phosphorus, 5, 10, 20, 30mg/L as well as 1.78mg/L of phosphate in control medium. The treatment of 5mg/L phosphate showed highest growth rate, 0.57 cell/h and lowest doubling time, 12.75 h. The third essential element, siliconof the diatom was tested in five concentrations, 10, 15, 25, 35, 45mg/L within the control treatment 5.7mg/L. The best for both growth rate, 0.83 cell/h and doubling time, 8.72 h were recorded at 10mg/L. So, new medium was suggested for cultivation of this alga.