The need for energy resource has increased due to the exponential increase in human population and industrialization, following suit. The concern towards environmental problems has made people embrace renewable energy resources which are more environmentally friendly. Thus, microalgae biomass are introduced as the promising energy source to substitute the limited supply of fossil fuel. The attached growth microalgae cultivation mode is employed to ease the harvesting process. The pH of the microalgae culture medium packed with polyurethane foam was adjusted daily to pH 2, 3, 4, 5, 6, 7, 8, and 9 in the individual photobioreactor. In this study, pH 6 was selected to be the favorable culture condition for both suspended and attached growth of Chlorella vulgaris with dry weight biomass of 0.075 ± 0.006g and 0.258 ± 0.003g, respectively, accompanied by a high lipid content attained at 0.394 ± 0.007 g/g. The attached microalgae biomass ease the harvesting process as the polyurethane foam was simply removed from the culture medium during the stationary stage while the suspended microalgae were harvested using the gravitational method. © 2018 Author(s).