Biofuels an alternative to traditional fossil fuels: A comprehensive review

Biofuels are fossil fuel alternatives produced from agricultural biomass or other organic matter; considered sustainable, eco-friendly, and bioeconomic biofuels have come up as a topic of discussion for over a decade. Their practical use depends on the production methods, low cost-technology implementation, and substrate used. This review gives an insight into different generations of biofuels with their applications and implications. First-generation biofuels are produced from edible biomass, but even in highly efficient processes, their yield isn't enough to cast them as a better alternative to conventional fuels. The second-generation biofuels are produced from non-edible biomass, where the substrate is eco-friendly and provides a sustainable use of solid waste, but the pretreatment is overpriced and sophisticated technology is needed to carry out the process. Third-generation biofuels are produced from substrates like seaweed or microalgae for which no specific area or separate cultivation process is required. Biofuels such as biohydrogen produced through microbial dark fermentation, bio-syngas generated via gasification, and biodiesel obtained through transesterification, have emerged as promising and environmentally friendly alternatives to conventional fuels. These biofuels have the potential to pave the way for a bioeconomic system of fuel production, offering economic viability and efficiency. However, extensive research conducted in the field of bioenergy, several challenges persist, hindering their commercialization prospects. To overcome the problems of first, second and third-generation biofuels, fourth-generation biofuels are under development using techniques like co-culturing, nanotechnology, and genetically modified organisms. Future generations of biofuels would set a system for a circular bioeconomic pathway for sustainable development in the fuel industry.