Sustainable seaweed biorefineries for achieving the sustainable development goals: biotechnology advances, challenges, and future prospects

Abstract While a linear economy can no longer sustain the emerging needs of the growing population, a focus on the circular economy, particularly in utilizing renewable energy, will greatly help in meeting the challenges, such as the energy crisis, environmental pollution, and rapid population growth. Hence, a seaweed refinery, similar to a petroleum refinery, helps sustain the production of various chemicals and fuels from seaweed. Seaweed (macroalgae) is a third-generation biomass used to produce biofuels and other products. It is greatly preferred for biofuel production owing to its high growth rate and yield. The maturation of seaweed biorefining technologies is illustrated by advancements in the production of bioethanol which can be produced at yields of 0.25–0.45 g per gram of sugar, biomethane which can be produced at yields of approximately 408 mL per gram of solid (VS) and biocrude which can be produced at yields from 12 to 30 percent by weight. Also, it is readily available and does not require fertilizers or pesticides for crops; hence, it forms a potential candidate for the production of biogas or biofuel. Besides, it is one of the most researched areas that has gained increased research attention in the last year, as it contributes to the Sustainable Development Goals. Though it is extensively used as a green energy source, there is a pressing need to develop novel technologies and materials to meet future energy needs. This review presents various cultivation techniques of seaweed and biotechnology developments for the better valorisation in biofuel production. Further, the major challenges, bottlenecks, and future opportunities of seaweed biorefineries are also discussed.