К. Velichkova*

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. Nitrogen is one of the most important limiting nutrients and nitrogen control is critical for the intensive cultivation of algae. The aim of the present study was to explore the effect of different nitrogensources on biomass accumulation in microalgae C. vulgaris during its cultivation in aquaculture wastewater. Microalgae cultivation was initiated in abioreactor from 500 ml Erlenmeyer flask containing 250 ml wastewaterfrom fish-ponds „Getov” – Pleven, Bulgaria. The cultures were kept at room temperature (25–27oC) at fluorescent light with a light:dark photoperiod of 12:12 h. The experiment was conducted in variants with urea (1.125g.l-1) and ammonium nitrate (1.125 g.l-1). The growth of the strain was checked for a 96-hour period. In the present study C. vulgaris showed better growth in wastewater from aquaculture with urea utilization as nitrogen source thanas a source of nitrogen ammonium nitrate.