Base-catalyzed transesterification for biodiesel production from microalgae oil

Abstract. Microalgae are considered promising third-generation feedstocks for biodiesel production due to their rapid growth, high lipid content, and reduced competition with agricultural land resources. This study aimed to develop and optimize a base-catalyzed transesterification process for producing biodiesel from oil extracted from microalgae. Two microalgae species, Chlorella sp. and Spirulina sp., were characterized in terms of protein, lipid, and carbohydrate content. Lipids were extracted from dried and ground biomass using ultrasound-assisted solvent extraction with chloroform:methanol 2:1. The purified algal oil was converted into fatty acid methyl esters through methanolysis in the presence of KOH as homogeneous alkaline catalyst. The effects of methanol:oil molar ratio, catalyst concentration, reaction temperature, reaction time, and stirring speed were evaluated. The optimal conditions were identified as methanol:oil ratio 6:1, KOH concentration 1.0%, reaction temperature 60°C, reaction time 120 min, and stirring speed 600 rpm. The physico-chemical properties of the obtained biodiesel complied with the limits imposed by the quality requirements for fatty acid methyl esters (EN 14214). The obtained results confirm the feasibility and potential of base-catalyzed transesterification for converting Chlorella sp. and Spirulina sp. oil into biodiesel.

Acknowledgement. This research was carried out through the Core Program within the National Research Development and Innovation Plan 2022–2027, with the support of MCID, project PN no. 23 05.