Growth and nitrogen uptake by Arthrospira platensiscultured in aquaculture wastewater from Nile tilapia reared in biofloc system

ABSTRACT

This study aimed to evaluate the growth of Arthrospira (Spirulina)platensiscultivated in Zarrouk culture medium and effluent from Nile tilapia (Oreochromis niloticus) reared in biofloc system. Four treatments were used Control (100% Zarrouk), E50 (50% Zarrouk + 50% Tilapia effluent), E75 (25% Zarrouk + 75% Tilapia effluent), and E100 (100% Tilapia effluent), and the experiment lasted 10 days. Growth parameters such as maximum cell density (MCD), doubling time (DT), and growth rate (K) were daily evaluated, as well aspH and water temperature. In addition, the concentrations of total ammonia nitrogen (TAN), nitrite-N (NO2-N), and nitrate-N (NO3-N) were analyzed in order to compare nitrogen absorption. Among treatments, E50 and E75 obtained higher maximum cell densities and presented an exponential growth rate similar to the control treatment. Regarding the concentrations of nitrogen compounds, a significant reduction was observed in all treatments, with an NO3-Nuptake of 99%, followed by 80% of TAN and 90% of NO2-N. Thus, giving the results obtained, besides being able to grow in wastewater, A. platensis can also be used in bioremediation processes, confirming the potential of this species.