The growth of microalgae Chlorococcum sp. isolated from Ampenan estuary of Lombok Island in Walne’s medium

Microalgae, also known as plankton, are one of the aquatic organisms which conduct photosynthesis similar to higher plants. Microalgae can live in any aquatic environment and are relatively easy to culture. There have been many studies that have shown the commercial applications of microalgae which have been continuously driving the development of microalgae-related research for decades. As for this research, the aim was to determine the growth phase of microalgae Chlorococcum sp isolated from Ampenan Beach estuary of Lombok Island. In this study, isolate from solid medium obtained from previous research were transferred to liquid medium enriched with Walne’s nutrition. The conditions of the culture were: room temperature (25 °C), light intensity of 2000-3000 lux, photo period of light:dark (24:0) hours, pH range 7-8, 24 hours of aeration, and culture under sterile environment. Based on every day observation of cell numbers, it is known that Chlorococcum sp began to enter the death phase on the fifth day so that the observations were only carried out for seven consecutive days. The initial cell number was 187,500 cells/ml and the optimum cell numbers (on the fourth day) was 331,250 cells/ml. In conclusion, the optimum growth of microalgae occurred on the fourth day from the first day of culture and it began to enter its death phase on the fifth day.