Evaluation of a microalgal–bacterial consortium for Cu and Zn removal using synthetic livestock waste solutions

Abstract

The essential livestock production has increased in recent years, leading to a rise in its waste generation. One strategy to repurpose this waste is its use as fertilizer. However, the presence of heavy metals such as copper (Cu) and zinc (Zn) poses a contamination risk, making their removal essential before application. This study explores the use of a natural microalgal-bacterial consortium (Nacelle), in which microalgae and bacteria interact to remove Cu and Zn from livestock waste–simulating solutions. Two strategies were evaluated: biosorption with dried biomass and bioaccumulation with living cells. Biosorption was faster, but bioaccumulation achieved higher efficiency, reaching 93.7% metal retention. Exposure to metals also induced changes in microbial composition, with enhanced bacterial growth and reduced microalgal abundance. This study constitutes an essential first step, highlighting the promising potential of the ‘Nacelle’ consortium for the safe reuse of livestock waste as fertilizer