Evaluation of biomass, growth, viability, and biochemical composition of Tetraselmis tetrathele using dairy and yeast wastewaters

Tetraselmis tetrathele is a species of saltwater that is widely used in industry and aquaculture due to its high nutritional value, bioactive compounds, and ease of cultivation. In this study, mass cultivation of this species was evaluated using effluent from dairy and yeast factories to evaluate growth, viability, and biochemical compounds (protein, fat, carbohydrate). The experiment was performed in a completely randomized design with six treatments; Conway, raw milk and yeast effluents as culture media, each in two modes, diluted (5 ml per liter of culture medium) and concentrated (10 ml per liter of culture medium) for 11 days. The results showed that this species was able to grow on dairy and yeast wastewaters, but the highest cell density in diluted Conway (9.12 × 106 cells per ml and 0.87 per day) and the highest specific growth rate in diluted yeast (6.68 × 106 cells per ml and 2.84 per day) were measured. However, the diluted raw dairy treatment had more survival than other treatments. The highest amount of protein and fat was obtained in the concentrated dairy treatment (44.6% and 9.71% of dry weight, respectively) and the highest amount of carbohydrates was obtained in the concentrated yeast treatment (31.49% of dry weight). Based on the specific growth rate, viability, and biochemical compositions it can be concluded that dairy and yeast wastewaters can be used as a suitable semi-industrial culture medium for mass cultivation of this species and it is recommended for the production of bioactive compounds and biofuels from the obtained biomass.