Abstract

• Microalgae play an important role in supporting the development of aquaculture because they can be used as natural feed for larvae due to their high nutrient value. The present study was to develop a cost effective and optimal growth of some marine microalgae such as Nannochloropsis sp., Chlorella sp. and Tetraselmis sp. by using two different culture media in laboratory condition. conway media for experiment I A1, B1 and C1, and agricultural fertilizer media for experiment II A2, B2 and C2 were used to culture microalgae. Three replications were prepared for each media. The cell densities of Nannochloropsis sp., Chlorella sp. and Tetraselmis sp. in different culture media were counted daily through the culture period. The results showed that the maximum population densities of Nannochloropsis sp. (8.80 x 10^6 cells/ml), Chlorella sp. (8.37 x 10^6 cells/ml), and Tetraselmis sp. (8.29 x 10^6 cells/ml) occurred on the fourth day with agricultural fertilizer media, while it was observed on the fifth day with conway media. The population densities of Nannochloropsis sp., Chlorella sp. and Tetraselmis sp. started to decrease in agricultural fertilizer media on fifth day while on sixth day in conway media. However, the agricultural fertilizer media had higher density than the conway media. It was concluded that the agricultural fertilizer media was the best for growth rate of Nannochloropsis sp., Chlorella sp. and Tetraselmis sp.