Microalgae Chlorella Species as Biofertilizer: Towards Sustainable Crop Nutrition and Environmental Benefits

Chemical fertilizers are widely used to achieve rapid and high-yield crop production. However, their intensive use negatively impacts ecosystems by polluting air and groundwater, accelerating soil acidification and deterioration, and because they rely on energy-intensive production processes and excessive mining. Biofertilizers have emerged as a promising and sustainable solution. Among them, microalgae, particularly species of the genus Chlorella, have attracted significant attention. Chlorella microalgae are an eco-friendly and cost-effective biofertilizer option, with advantages such as ease of cultivation, fast growth and slow release of nutrients when applied to soil. In this context, this review summarizes the potential of Chlorella species as biofertilizers and highlights the important role of its phytohormones in this effect, in addition to its use in wastewater treatment, which results in biomass and water with biofertilizing potential.