Microalgal Biodiesel Fuels: Spectroscopic and Physicochemical Characterization and Life-Cycle Assessment toward CO₂...

Area of Science:

• Biotechnology and Renewable Energy
• Marine Biology and Algal Research
• Chemical Engineering and Fuel Science

Background:

• Marine microalgae are recognized as sustainable feedstocks for renewable energy production.
• Nannochloropsis oculata is a promising candidate for biofuel generation due to its rapid growth and lipid content.
• Assessing the full lifecycle impact and fuel quality is crucial for widespread adoption of algal biofuels.

Purpose of the Study:

• To evaluate Nannochloropsis oculata as a sustainable marine feedstock for biodiesel production.
• To integrate physicochemical characterization, spectral analysis, and life cycle assessment for comprehensive evaluation.
• To establish the suitability of N. oculata biodiesel as a viable alternative to fossil fuels.

Main Methods:

• Fourier-transform infrared (FTIR) spectroscopy for functional group analysis.
• Gas chromatography-mass spectrometry (GC-MS) for fatty acid methyl ester (FAME) profiling.
• UV-vis and photoluminescence spectroscopy for purity and band gap analysis.
• Standardized tests for biodiesel properties (viscosity, density, calorific value).
• Cradle-to-grave life cycle assessment (LCA) for greenhouse gas (GHG) emissions.

Main Results:

• FTIR confirmed ester functional groups; GC-MS showed 94.47 wt % FAME content (C12-C23).
• Spectroscopic analysis indicated low aromaticity, a 3.24 eV band gap, and 52% quantum yield.
• Biodiesel properties met ASTM standards: viscosity 4.59 mm²/s, density 0.886 g/cm³, calorific value 40.5 MJ/kg.
• LCA revealed 50-70% lower GHG emissions than fossil diesel and net CO₂ sequestration.

Conclusions:

• Nannochloropsis oculata derived biodiesel exhibits high molecular integrity and meets regulatory fuel standards.
• Integrated spectral and physicochemical analysis provides a robust method for fuel quality assessment.
• Marine microalgal biodiesel offers significant environmental benefits, including reduced GHG emissions and carbon sequestration, supporting its role in sustainable energy.