The feasibility of immobilized Chlorella vulgaris cultivated in palm oil mill effluent for lipid and fatty acid methyl ester production

Abstract

The abundance of palm oil mill effluent (POME) in Malaysia had exposed an opportunity for the researchers to replace the common culture for microalgae cultivation process. However, the small size of microalgae bring difficulties in the separation process from the culture medium. Thus, immobilization technique had been implemented in this study to simplify the separation process of microalgae Chlorella vulgaris. A new immobilized C. vulgaris consisted of combination matrix (sodium alginate (SA), calcium alginate (CA) and sodium carboxymethyl cellulose (CMC)) with volumetric ratio (Matrix:Microalgae) 0.3:1 were utilized in this experiment. The feasibility of POME as a cultivation medium was determined by cultivating the immobilized C. vulgaris in different concentration of POME (20–100%). Two types of media were explored in this study which were POME mixed with distilled water (DW) (0–80%) and POME mixed with Bold Basal Medium (BBM) (0–80%). Based on the cell density result, the medium with 20% POME + 80% DW and 40% POME + 60% BBM medium performed the highest number of cells with 1.63 × 109 cells/mL and 0.59 × 109 cells/mL, respectively. Meanwhile, the the POME mixture medium showed the potential as a cultivation medium for the immobilized microalgae. The lipid extracted from immobilized microalgae beads cultivated in BBM media were the highest with 48.03 ± 3.7%, followed by 20% POME + 80% DW (38.14 ± 2.2%) and the lowest by 40% POME + 60% BBM media (32.93 ± 2.8%). Besides, the FAME produced from oil extracted using immobilized microalgae biomass cultured in POME mixture medium showed a good quality of oil. Thus, the oil produced revealed the potential for biodiesel production.