Biodiesel production from microalgae using lipase-based catalysts: Current challenges and prospects

The excessive demand for fossil fuels has caused severe environmental impacts, such as GHG-related effects and widespread pollution. Firstly, it is essential to identify the main problems arising from fossil fuel production and consumption, which will enable the search and implementation of technological, sustainable, and economical alternatives to mitigate the current issue. With the modern technological advances in this specific area, the use of biofuels has expanded, given their high potential of production from diverse classes of biomass. Producing biodiesel from microalgae oil specifically, as a way of obtaining clean and renewable energy, can play a significant role in this context, and the process is of high interest to the energy sector. Biodiesels are produced through mixtures of ethyl esters or fatty acid methyl esters, which are generated by the synthesis of oil with alcohol in the presence of the enzyme alcohol lipase. There are clear challenges linked to the new technologies employed to obtain biofuels from microalgae, and there also are strong prospects to these approaches, since they are very energy-efficient and environmentally friendly. Thus being, the present review describes the main aspects associated with biodiesel production from microalgae, highlighting the fundamentals of the technique, the immobilization processes followed, the use of solvents to optimize reaction media, bioreactor systems, as well as the performance optimization of microalgae biodiesel-based engines, while considering important economic and environmental aspects. Future trends in the biofuel scientific research and industry are also included, aiming at fostering discussions on the development of other significant advances in the use of microalgae lipase and oil technology for biodiesel production.