Biofuel Production Metrics from Marine Microalgae Species (Chlorella and Nannochloropsis)

Agriculture

Global energy crises and environmental impacts from fossil fuels have prioritized microalgae as third and fourth-generation biofuel feedstocks. This study analyzes production metrics for the genera Chlorella and Nannochloropsis, focusing on lipid accumulation for biodiesel and carbohydrate yields for bioethanol. Nannochloropsis sp. exhibits high lipid contents ranging from 31% to 68% of dry weight, while Chlorella vulgaris can reach 55% under optimized nutrient limitations. Extraction techniques such as NaCl osmotic shock (120 atm) and microwave irradiation have been shown to significantly enhance oil yields and efficiency. For bioethanol, Chlorella pyrenoidosa provides a carbohydrate reservoir of 37-55%, yielding up to 28.07% bioethanol through enzymatic hydrolysis and fermentation. Physical metrics of produced biodiesel, including a density of 0.84 g/mL and an average cetane number of 52, comply with international standards. This review integrates 20 distinct studies to provide a comprehensive metric-based evaluation of marine microalgae as a sustainable energy factory.

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