This research examines microalgae as a promising source for biofuel production, currently contributing 6.8% of the world's energy (as of 2020). The study analyzes the complete lipid production process for biofuel, from cultivation through extraction, separation, and purification. It compares conventional technologies with innovative systems like smart photobioreactors and "milking" techniques. The research emphasizes the biorefinery concept as the most economically viable approach for commercial-scale microalgae cultivation, where multiple high-value compounds are extracted from the same biomass rather than focusing on a single product. The paper identifies lipid extraction as the most expensive and energy-intensive stage in the production process, suggesting optimization opportunities.
The environmental impact of microalgae biofuel production is significant: Greenhouse gas reduction: Biofuels from microalgae release approximately 10% less CO2 and up to 30% less SO2 compared to traditional fossil fuels. Energy balance: The Net Energy Ratio (NER) is critical for determining environmental viability. An NER > 1 indicates a net gain in usable energy, resulting in significant GHG reductions. Carbon capture: Microalgae cultivation actively captures CO2 during photosynthesis, potentially offering carbon sequestration benefits. Energy consumption challenges: The harvesting and extraction phases are extremely energy-intensive, with dewatering accounting for up to 30% of total processing costs. Biomass harvesting through centrifugation and press filtration consumes 90% and 79% of total energy requirements, respectively. Sustainable alternatives: The paper suggests the "milking" process as a potential solution to eliminate energy-intensive dewatering, allowing for multiple extractions from the same microalgae batch.
The study employs a comprehensive literature review methodology to analyze each stage of the microalgae biofuel production process: