The employment of attached microalgal cultivation in simplifying the microalgal harvesting process and reducing its associated costs has attracted much attention recently. As such, palm kernel expeller (PKE), a by-product generated from palm oil extraction process was used to grow attached microalgal biomass. Thorough characterization of PKE had suggested its potentiality in enhancing microalgal cell density. Owing to the high carbon content which improves the microalgal density and low moisture content which could prevent contamination in cultivation medium, PKE theoretically proves that it is a fit choice to be used as carbon source of growth. With regards to this, cultivation conditions such as concentrations of PKE and light intensities were varied using Response Surface Methodology (RSM) simulation software to determine these parameters influence in leveraging the dry biomass concentrations. Results obtained showed that higher dosage of PKE had significant improvement on the dry attached biomass concentration. However, the light intensity factor was found to be of least significance in this context. Correlation of these two factors in maximizing the attached microalgal biomass was obtained at PKE dosage of 2 g/L and light intensity of 60 μmol/m2s. © 2022 Author(s).