Assessment of Wastewater Elements on Growth, Chlorophyll, and Reduction of Nitrate and Phosphate by the Marine Cyanobacterium Fischerella muscicola ISC123

Wastewater from different parts and industries have compounds, including nitrate and phosphate, that seriously affect ecosystems and environments. Remediation and treatment of these compounds are usually performed by physical, chemical, and biological methods. Since cyanobacteria have high nitrate and phosphate requirements, wastewater (sewage/ municipal mixed waters) with high loads of these nutrients can serve as a culture medium to enhance their growth and indirectly reduce the nutrient load, making it useful for other applications. So, in this research, the role of these elements in artificial wastewater as a culture medium on growth, chlorophyll contents, and removing potential of nitrate and phosphate by the marine cyanobacterium Fischerella muscicola ISC 123 is investigated. Our specimen was collected from the Caspian Sea, isolated, and identified according to the 16SrRNA. Wastewater treatments were designed in 15 runs using Design-Expert software, and the sample was cultured in BG110 medium with various amounts of NaCl, NaNO3, and K2HPO4. Growth(O.D.), chlorophyll contents (methanolic extract), changes of nitrate and phosphate of cultures by standard methods, and effects of elements were analyzed by Response Surface Methods (RSM) of Design-Expert. The enhanced growth rate, chlorophyll content, and nitrate and phosphate removal were observed in runs 2, 6, and 14. NaCl reduced growth while most interactions of elements were compatible with the results of practical experiments. According to the results, run14 (NaCl 1%, NaNO3 350, K2HPO4 77 mg L-1) had the optimum condition for growth and removing nitrate and phosphate of F.muscicola. It can be concluded that removing nitrate and phosphate depends on the growth factors, and by studying and optimizing wastewater elements as culture media, microalgae can have the optimum growth and the most refining potential.