Effect of medium type, light intensity, and photoperiod on the growth rate of microalgae Chlorococcum sp. local isolate

Abstract

Microalgae are microscopic organisms that are living in a watery environment, whether in fresh or seawater. As photosynthetic organisms, microalgae are the primary oxygen producers in the water. Furthermore, microalgae have various benefits for the sustainability of human beings. Chlorococcum sp. is green microalgae found in freshwater, seawater, brackish water, or even in wastewater. Publication data on this microalga are limited, but this alga is known for its high lipid content. Previously, Chlorococcum sp. was isolated from the Ampenan Estuary of Lombok Island and grown in a liquid medium using Walne’s. The purpose of this study was to determine the optimum growth factors for the cultivation of Chlorococcum sp. The microalgae growth factors that were varied as treatments were the source of water medium used (distilled water, seawater, and saline water), the light intensity (2000, 25000, 3000, and 3500 lux), and the photoperiod (16: 8; 20:4; and 24:0 hours). Based on the research data, it is known that the type of water media is very influential on the productivity of microalgae. Where the highest growth of Chlorococcum sp. was produced in a medium containing saline water. In addition, the number of cells in the initial culture also affects the life span of microalgae. The treatment with the lowest initial cells caused the cell death phase to be extended, starting from the 11th day of culture. In conclusion, the optimal growth of Chlorococcum sp. occurred on the 5th day with a cell density of 323×104 cells/ml.