At IRDL, Yiru Zhao explored the production of biohydrogen from sargassum to valorize this marine biomass.
Yiru Zhao, chercheur·e au sein de IRDL (Institut National Polytechnique de Bretagne).
Thèse soutenue en 2024 à l'école doctorale École doctorale Sciences Pour l'Ingénieur (Lorient ; 2022-....).
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
Yiru Zhao's thesis, conducted at IRDL, addresses a burning current issue: the energy valorization of sargassum, these brown macroalgae that massively wash up on the coasts of the Caribbean, particularly in Guadeloupe. With quantities reaching between 20,000 and 40,000 tons per year on the Guadeloupean coastline, these algae represent both a major environmental challenge and an unprecedented economic opportunity. Indeed, the proliferation of sargassum causes ecological nuisances, impacting marine biodiversity and tourism activities, while also offering a potentially rich raw material for energy production. Zhao's research focuses on the production of biohydrogen, a promising energy vector, from co-products derived from the biorefining of Sargassum sp.
The process of converting these algae into biohydrogen is complex due to their recalcitrant structure. Zhao highlights innovative methods such as dark fermentation and anaerobic digestion. These techniques help overcome some of the scientific barriers related to the production of methane and hydrogen, two key elements in the energy valorization chain. For example, dark fermentation, which occurs without light, can be particularly effective in breaking down the complex polysaccharides present in the algae. Preliminary results from her research show that Sargassum muticum could offer a hydrogen yield four times higher than that of Caribbean algae, which could transform the way we view the management of sargassum and their energy potential.
It is essential to ask the question: how can we leverage this marine biomass to meet our energy needs while mitigating environmental impacts? Zhao's thesis is not limited to a simple theoretical study. It proposes strategic recommendations to encourage the energy valorization of sargassum, emphasizing the importance of an integrated approach that combines research, innovation, and public policies. For example, establishing partnerships between researchers, local businesses, and governments could promote the development of pilot projects to test the economic viability of these new technologies.
The economic implications of this research are significant and deserve to be highlighted. By valorizing this biomass, we not only reduce the costs associated with their management, but we also create job opportunities in the renewable energy and waste management sectors. The energy transition in island environments could thus benefit from a boost by integrating sustainable and local solutions. For instance, local initiatives could emerge, such as cooperatives of fishermen transforming sargassum into biohydrogen, thereby contributing to the creation of a circular economy.
In summary, Yiru Zhao's research paves the way for a broader reflection on the management of marine resources and the energy transition. Policymakers must take these results into account to develop policies that promote innovation and sustainability. In a context where climate issues are becoming increasingly pressing, it is crucial to develop solutions that combine economic development and environmental preservation. By integrating the results of this thesis into regional strategies, Benin and other West African countries could not only improve their energy security but also strengthen their resilience to growing environmental challenges. Thus, the valorization of sargassum could become a model to follow for other regions facing similar issues, proving that waste can be transformed into resources, provided that an innovative and collaborative approach is adopted.
Données clés
- 20 000 à 40 000 tonnes : quantité de sargasses échouées chaque année sur le littoral guadeloupéen.
- quatre fois supérieur : rendement en hydrogène de Sargassum muticum par rapport aux algues antillaises.
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Sources et accès
Yiru Zhao. Production de biohythane à partir de coproduits du bioraffinage de macroalgues pélagiques brunes : application à Sargassum sp.. Génie des procédés. Université de Bretagne Sud, 2024. Français. ⟨NNT : 2024LORIS712⟩. ⟨tel-05263641⟩