Low-carbon biofuels from macroalgae towards a sustainable circular bioeconomy and green future

The increasing demand for all types of energy is driving the biofuel sector in transportation to innovate technologies for a more energy-efficient future by synergistically utilizing various energy sources. Current fossil fuel reserves are insufficient to meet rising energy demands and are expected to be depleted soon. Factors such as pollution, global warming, and high oil prices have driven the search for renewable energy sources. Marine macroalgae have garnered considerable interest as a promising and sustainable resource for producing value-added chemicals and biofuels because of their high carbohydrate and lipid content, high availability, and low cost of production. Extensive research has been conducted to evaluate its potential for producing biofuels, especially in the light of rising recognition regarding socio-economic considerations. Incorporating biorefinery methodologies into the biofuel production presents significant promise for promoting the widespread advancement of a circular bioeconomy. The techno-economic and environmental assessment of biofuel production from macroalgal biomass has been the subject of much research. This review briefly explores various thermochemical and biochemical conversion technologies of macroalgal biomass into biofuels. It also illustrates the biofuel generation pathway, efficiency, and recent techniques to accelerate the product yield. The review also discusses the limitations, bottlenecks, challenges, and future perspectives of utilizing macroalgal biomass to produce biofuels and value-added chemicals. [Display omitted] •Biofuels meet the demands for clean, independent, and sustainable energy worldwide.•Macroalgae holds great potential as a biofuel feedstock for a sustainable circular bioeconomy.•Macroalgae can mitigate climate change by rapid carbon assimilation and promote oceanic carbon sink.•Both thermochemical and biochemical conversion of macroalgae biomass is feasible.•Valorization of waste seaweed biomass promotes circular bioeconomy.