Evaluating poultry excreta leachate for algal biomass and biodiesel production for resource recovery and circular economy

Finding sustainable and eco-friendly solutions for managing poultry waste is imperative to environmental safety and to maintain the circular economy. This study evaluated the poultry excreta leachate (PEL) as a growth medium for algal strains Oedogonium sp., Cladophora sp., Ulothrix sp., and Spirogyra sp. The results indicated a substantial 80% increase in biomass of Oedogonium sp., Ulothrix sp. 86%, Cladophora sp. 48%, and Spirogyra sp. 24% under PEL application. Increase of biomass was coupled with enhanced carbohydrate levels (76, 82, 80, and 89%) in each species respectively. Protein accumulation elevated only to PEL50% at day 10th, showing increases of 90–140% compared to control. Lipid increased by 58% in Oedogonium sp. (51%), in Ulothrix sp. (52%), in Cladophora sp. (66%), and in Spirogyra sp. Higher accumulation of fatty acid profiles, particularly C16:0 and C18:1, contributed to improved heating value and oxidative stability of biodiesel. On the other hand, nutrient removal was maximum in Oedogonium sp. (96% for nitrate and 80% for total nitrogen) while Ulothrix showed about 96% inorganic phosphate removal from the growing medium. These findings suggested that PEL is an effective substrate for enhancing algal cultivation and promoting nutrient recycling in sustainable agricultural practices.