Undaria Pinnatifida as a Biofuel Feedstock: Challenges and Opportunities

Undaria pinnatifida, popularly known as wakame, is a brown kelp that thrives in cold water. Given its nutrient-rich composition and bioactives, it has extensive application prospects in various industries, e.g., food, cosmetics, animal feed, and bioremediation ^1,2. One emerging use is biofuel production ³. In this connection, research on economically and technically viable approaches to successfully commercializing third-generation renewable biofuels is crucial ⁴. Seaweed is generally a more efficient converter of solar energy because its cells grow in an aqueous suspension, which gives them ready access to CO₂, water, and other nutrients ⁵. Its high oil content relative to its dry weight qualifies it as a candidate for conversion through various processes, e.g., transesterification, pyrolysis, and direct combustion ⁶. Based on laboratory data, the higher heating value (HHV) of U. pinnatifida was 2553.5 kcal kg⁻¹, which is suitable for biofuel production. Still, this value is lower than that of wood-derived biomass (≈4500–5000 kcal kg⁻¹). However, the volatile fraction (50.2%) of U. pinnatifida makes it feasible for gasification with high generation of combustible gases (H₂, CO), a process that is key to the synthesis of renewable synthetic gas. This overcomes the drawback of low HHV by expanding the scope of energy products. Thus, it could be an up-and-coming option for local circular bioenergy systems in coastal areas, as it can grow in waters unsuitable for agriculture and does not compete with food crops, ideal for biodiesel, bioethanol, biogas, and biohydrogen. Further studies are needed to develop and test existing hypotheses.