The accumulation of Marine Macroalgal Waste (MMW) - drifted marine macroalgae - is a growing phenomenon. The lack of appropriate management protocols for this residual biomass leaves it mostly unmanaged or disposed of in landfills. Such inappropriate solutions lead to negative environmental impacts, health concerns and coastal degradation, representing an opportunity to develop the bioeconomy. Although a relevant number of studies exists on the use of edible marine macroalgae for several purposes, there is generally a lack of information concerning MMW valorisation, at both local and global scales. This review thus explores the ecological and biotechnological potential for the establishment of a new approach for MMW valorisation based in the circular and blue economies. It is supported in literature on the use of residual biomass whenever possible and also includes studies with fresh biomass to extrapolate, considering known characteristics of MMW; consequently, a roadmap for its utilisation is provided. The review includes characteristics of various seaweeds, MMW accumulation worldwide and traditional uses, together with the development of alternative and integrated valorisation strategies. By analysing a large number of studies, it was possible to perceive a clear potential to explore MMW to obtain renewable fuels, especially biogas and bioethanol and for use in agricultural activities. Allied to this, the extraction of value-added compounds, such as lipids, pigments, phenolic compounds and specific polysaccharides is highlighted, aiming to contribute to the development of an economically feasible zero-waste biorefinery approach.

海洋大型藻类废物（MMW）的积累——漂流的海洋大型藻类——是一种日益严重的现象。由于缺乏对这种剩余生物质的适当管理协议，它大多无法管理或被丢弃在垃圾填埋场。这种不适当的解决方案会导致负面的环境影响、健康问题和沿海退化，这代表了发展生物经济的机会。尽管存在大量关于将食用海洋大型藻类用于多种目的的研究，但在当地和全球范围内普遍缺乏有关 MMW 增值的信息。因此，本综述探讨了建立基于循环和蓝色经济的 MMW 增值新方法的生态和生物技术潜力。文献支持尽可能使用剩余生物质，还包括使用新鲜生物质进行推断的研究，考虑到 MMW 的已知特征；因此，提供了其使用路线图。审查包括各种海藻的特征、全球 MMW 积累和传统用途，以及替代和综合增值战略的发展。通过分析大量研究，可以看出探索 MMW 以获得可再生燃料（尤其是沼气和生物乙醇）并用于农业活动的明显潜力。与此相关的是，突出了增值化合物的提取，例如脂质、色素、酚类化合物和特定多糖，