Fourth Generation Biodiesel: A Review of Technology Development, Challenges, and Future Prospects

The need to combat climate change has accelerated the global energy transition from fossil-based sources to renewable energy, such as biofuels. Among other biofuels, fourth-generation biodiesel that is derived from genetically modified microalgae (GMO) combined with carbon capture systems stands out as a promising approach. In contrast to carbon-neutral alternatives, this biodiesel is also regarded as achieving carbon-negative energy generation by capturing and storing carbon. Due to the extensive review papers available on first- to third-generation biodiesel, the present manuscript focuses on fourth-generation biodiesel which utilises GMOs and carbon capture for production. This manuscript provides broad information about the benefits, limitations, and characteristics of the fourth generation of biodiesel. It also reviews technological advancements, including the genetic modifications of microalgae and the incorporation of carbon capture for producing fourth-generation biodiesel, along with the associated challenges and future directions. It is suggested that modifying microalgae strains could increase lipid accumulation by two to three times, thereby increasing the production of biodiesel. The study also demonstrates the survival of microalgae in 8,000-L open raceway ponds fed with flue gas from coal-fired power plants.