Recent progress in extraction/transesterification techniques for the recovery of oil from algae biomass

Exploration of alternative and sustainable sources of fuel production has become vital for a couple of decades because of the increase in demand, shortages in inexpensive fossil fuel production, and environmental pollution caused by their derivatives. Although a variety of renewable energy alternatives are currently available, energy derived from natural microalgae associated with bacteria seems promising because it flourishes in all natural environments, along with contributing to the carbon cycle. Lipid extraction from different microalgae cells is a significant boundary for the biofuel business because of the multifaceted nature of the procedure and cell structure of the microalgae. Although the current existing dry extraction methods for lipid extraction from algae are in use, the drying of microalgae is consuming more energy than the extraction itself. There is still lack of technology to optimize the extraction of biodiesel from microalgae in a cost-effective and quick way. Studies show that eliminating the drying step and extracting lipids in one step can be optimal by adding mechanisms like supercritical method, ionic liquids, Eutectic solvents, and transesterification. A major constraint in this process is effective lipid extraction technique. Fuel production from wet microalgae biomass is significantly desirable because it would eliminate at least two lengthy processes (dewatering and drying) that consume much energy. In this study, wet extraction techniques are comprehended. For implementing and optimizing this application, further research and exploration are much needed. Graphical abstract