Leachate as an alternative culture medium for microalgae growth: Perspectives and challenges

Abstract The growing demand for renewable energy sources and sustainable technologies positions microalgae as a promising alternative, given their ability to produce biomass rich in lipids, which can be converted into biofuels. In the same scenario, the leachate produced by the decomposition of organic waste along with the infiltration of rainwater represents one of the main current problems associated with landfills. In this context, the leachate can be transformed into a valuable opportunity by being used as a culture medium for microalgae, providing the essential nutrients for the growth of these microorganisms and contributing to the production of sustainable bioproducts such as carbohydrates, lipids, proteins, and pigments. This approach plays a crucial role in bioremediation by removing toxic compounds and reducing the environmental impact of leachate. Thus, by integrating microalgae cultivation with the reuse of leachate, not only is a clean energy source obtained, but also the promotion of a circular economy is achieved, turning waste into resources. This review critically synthesizes the current literature on microalgae cultivation in landfill leachate, highlighting technological advances, biomass valorization, and their environmental implications, thereby providing a comprehensive framework to guide future research and industrial applications.