Production of methyl ester from two microalgae by two-step transesterification and direct transesterification

Area of Science:

• Biotechnology
• Renewable Energy
• Chemical Engineering

Background:

• Microalgae are a sustainable source for biofuel production.
• Efficient extraction and conversion of algal lipids are crucial for economic feasibility.

Purpose of the Study:

• To optimize oil extraction from Chlorella sp. and Scenedesmus sp.
• To evaluate the transesterification process for biodiesel production.
• To assess the industrial applicability of the developed methods.

Main Methods:

• Investigated various cell disruption techniques, with ultrasound proving most effective.
• Compared different solvent systems, identifying hexane as optimal for oil yield.
• Analyzed kinetic parameters, activation energy, and thermodynamic properties of the extraction process.
• Performed direct and two-step transesterification to produce methyl esters (biodiesel).

Main Results:

• Ultrasound disruption and hexane solvent yielded maximum oil from both microalgae species.
• Extraction kinetics followed first-order reactions, with endothermic, irreversible, and spontaneous characteristics.
• Biodiesel yields reached 96% for Scenedesmus sp. and 92% for Chlorella sp.
• Methyl ester properties complied with ASTM D6751 standards.

Conclusions:

• Ultrasound-assisted hexane extraction is an efficient method for Chlorella and Scenedesmus.
• The transesterification process is highly effective, producing biodiesel suitable for commercial use.
• The overall process demonstrates potential for large-scale, sustainable biodiesel production.