Nutrient Recycling in Microalgae Cultivation as a Sustainable Process for Biomass Production

Microalgal production has garnered increasing interest from both researchers and industry due to the wide range of biomass applications in food, feed, cosmetics, and pharmaceuticals. The successful cultivation of microalgae requires not only adequate supply of nutrients but also large volumes of water. The development of green technologies aimed at sustainable microalgae biomass production is expanding, though it presents several technological challenges. Recycling spent culture media and nutrients has emerged as a promising strategy to reduce water consumption and cultivation costs while supporting environmentally friendly practices. In this review, we first highlight the role of macro- and micronutrients in microalgal growth, then examine physicochemical and physical treatments for optimizing medium reuse, discuss the economic aspects of microalgae production, and outline key technologies for sustainable cultivation. The review underscores the potential of medium recycling to significantly lower costs and environmental impact, paving the way for a more sustainable and economically viable microalgae industry.