High ammonia tolerance on growth rate of marine microalga Chlorella vulgaris

• Published in: Journal of environmental biology 2018-09, Vol.39 (5(SI)), p.843-848
• Main Authors: Goto, M., Nagao, N., Yusoff, F. Md, Kamarudin, M.S., Katayama, T., Kurosawa, N., Koyama, M., Nakasaki, K., Toda, T.
• Format: Article
• Language: English
• Subjects: Algae; Algal growth; Ammonia; Ammonium; Aquaculture; Cell density; Chlorella; Chlorella vulgaris; Culture media; Effluents; Emissions; Environmental science; Growth rate; Microalgae; Nitrogen; pH effects; Productivity; Wastewater; Wastewater treatment; Weight
• ISSN: 0254-8704; 2394-0379
• DOI: 10.22438/jeb/39/5(SI)/4

Aim: In order to evaluate the effects of ammonia on microalgae growth, Chlorella vulgaris was cultivated in ammoniumnitrogen. Methodology: The marine microalgae, Chlorella vulgaris was cultivated in algal media containing increasing concentrations of ammonium concentrations at 320,640,960,1600 mg l-1, with free ammonia concentrations of 0.64 to 2.97 mM and pH ranging from 7.78 to 7.82. An addition ammonia treatment was 1600 mg l-1 that had a free ammonia concentration of 13.30 mM, whilea control was NaNO3 at 100 mg l-1. Results: C. vulgaris grew faster when cultured using ammonium nitrogen than nitrate nitrogen. The dry weight of C. vulgaris increased even under extremely high ammonium conditions of 1600 mg-N l-1, which initially contained 2.97 mM free ammonia and reached around 4 g-ds l-1. Algal growth was inhibited in the beginning of the experiment at the highest initial free ammonia concentration of 13.30 mM. However, the cell density increased 2 days later when free ammonia concentration decreased to 3.7 mM due to decrease in pH from 8.48 to 7.88, and the maximum area productivity of 21.12 g-ds m-2 d-1 was observed. Interpretation: These results showed that C. vulgaris could maintain high productivity even in high free ammonia concentrations of 3.7 mM. Because of the high tolerance for free ammonia compared with other microalgae, C. vulgaris can be used for the aquaculture industry by removing ammonia from wastewater, and thus improving thewater quality.