in control condition. However, at 30 ppt protein content was significantly higher (p < 0.05) compared to 40 ppt. The protein contents of Nannochloropsis sp. and Tetraselmis sp. in response to pH 5.5, 7.5, 8.5 and 9.5 under natural and control condition were shown in Fig. 6. The output of this study showed that the optimum pH for the growth of Nannochloropsis sp. and Tetraselmis sp. were at pH 7.5 and 8.5, respectively.