Unlocking the potential of brewery wastewater: Sustainable cultivation of Arthrospira platensis for biomass and phycocyanin production

Breweries generate large volumes of wastewater, traditionally treated through aerobic processes that leave residual pollutants and emit substantial COQ. Integrating microalgae cultivation into wastewater treatment offers a sustainable alternative, enhancing effluent quality while sequestering COQ. This study evaluated the nutrient recovery, growth and pigment production potential of Arthrospira platensis (Spirulina sp.) strains using brewery wastewater as a cultivation medium. Strain ULC 0444 showed the best performance among the other studied strains, achieving a specific growth rate of 0.293 day- 1 and a phycocyanin yield of 269.2 mg center dot L-1 under red light and 3 % COQ. Palmitic acid (C16:0) was the dominant fatty acid across all studied conditions, and it peaked under pink light by 688 +/- 58 mg. gDW- 1. The white light cultivation yielded a balanced characteristics for biodiesel. Residual biomass after pigment extraction was used for biogas production, achieving a maximum methane yield of 93 mL CH4 center dot gVS- 1 at an S/I ratio of 2. This approach demonstrates the feasibility of brewery wastewater for A. platensis cultivation, enabling effective wastewater treatment, COQ capture, and bioproduct generations. The system supports a circular economy by reducing brewery environmental impacts and generating valuable outputs, including pigments, fatty acids, and biogas, ensuring environmental and economic sustainability.