The wastewaters have different nutrients that could be applied as rich culture media for algal cultivation. The marine green microalga Tetraselmis tetrathele is one of the important species in the marine aquaculture activities. In this research, the growth, viability, proximate and fatty acids composition were evaluated by cultivation of T. tetrathele on mollas and beer waste water in low and high concentrations. The experiment ran with six- different treatments; low and high Conway (LC, HC), low and high mollas (LM, HM) and low and high beer (LB, HB), for 11 – days. Results showed that this algae can be cultured on raw beer and mollas waste waters, but the highest cell density (96.7×10 3 cell/ml) was in the HM treatment and maximum SGR (15.5 /day) were obtained in the LC treatment. The cell viability in the T. tetrathele cultured on HB treatment had the highest percentage (Up to 100%) compared to other treatments. The protein and lipid contents were the highest in the HB while the carbohydrate was the highest in the LM treatment. The protein, lipid and carbohydrate ranged as 10.70- 39.5, 2.98- 8.14 and 5.98- 28.92, respectively. Based on fatty acids composition, the content of SAFA, MUFA and PUFA were 45.24, 37.8 and 16.94 in HC; 21.38, 38.38 and 40.21 in LC; 42.3, 32.39 and 25.29 in HB; 42.6, 40.28 and 17.1 in LB; also 27.44, 50.53 and 22.02 in HB; 47.19, 30.11 and 22.68 in LB. In addition, the total content of n-3 and n-6 were obtained as 2.12 and 15.08 for HC; 20.26 and 19.95 for LC, for HB 12.98 and 12.31; for LB 2.42 and 14.68; and for HM 2.11 and 19.91; for LM 5.33 and 17.35. Furthermore, the highest SAFA, MUFA and PUFA were measured in the treatments of LM, HM and LC treatment, respectively. Of the SAFA, MUFA and PUFA, the fatty acids of C16:0, C18:1 and C18:2n-6, were highest, respectively. The ratio of n-3÷n-6 was highest in the high beer treatment. The findings of this study showed that beer and mollas wastewaters could be suitable for the media production of T . tetraselmis algae with a suitable fatty acid profile. Keywords: Beer, Fatty acid, Growth, Microalga, Mollas, Tetraselmis tetrathele , Viability
