Analysis of Extraction and Transesterification Conditions for Phaeodactylum Tricornutum Microalgae

Abstract

An increasing global demand for a biologically produced energy source has emerged due to the exhausted usage of non-renewable petroleum-derived fuels. Microalgae are a promising feedstock for biofuels because of their capability to produce lipids. In this paper, two operations for biodiesel production were studied from Phaeodactylum Tricornutum microalgae. This marine diatom shows a big potential to produce biodiesel due to its fast growth and lipid accumulation ability. In this research, first the microalgae was harvesting using an inorganic flocculant as copper (II) sulphate (CuSO4). When the dose was 200 mg/L, the microalgae recovery was close 83% in the first five minutes. After that, the microalgal oil was separated by ultrasound extraction process, using ethanol as solvent. This allows to analyze the oil content of the microalgae which is used later in the transesterification. The obtained lipid content was 38% wt. Temperature variations were observed in this process. Finally, a direct transesterification reaction took place with base catalysis by three ways: traditional, microwave assisted and ultrasound assisted. Direct transesterification microwave assisted achieved 52% conversion to biodiesel versus 16% for the traditional method. However, the best performance (90%) was obtained for ultrasound assisted transesterification.

Keywords: microalgae; harvesting; transesterification: microwave; ultrasound; extraction.

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