Microalgae as Biofertilizers: A Sustainable Way to Improve Soil Fertility and Plant Growth

Abstract

The intensification of agricultural production in response to the global population increase and the growing demand for food has raised significant concerns regarding environmental impacts over the past few decades. Currently, modern agriculture aims to improve the quantity and quality of crop yield, minimizing the negative effects of treatments on the environment. Recently, microalgae have found extensive application as a valuable biological resource across multiple industries, including the food sector, biofuel production, and the pharmaceutical industry. In agriculture, microalgae have been seen as a promising and sustainable alternative to agrochemicals, offering a range of benefits to improve soil fertility, optimize nutrient management, and reduce reliance on synthetic fertilizers. In general, microalgae have demonstrated efficient nutrient cycling abilities, assimilating and converting essential nutrients, such as nitrogen, phosphorus, and potassium, into forms readily available for plants. Additionally, they produce bioactive substances, including phytohormones, which have a direct impact on the physiological processes of plants and promote their growth. Microalgae can also establish beneficial interactions with other soil microorganisms, supporting the growth of beneficial bacteria and fungi, thus promoting a healthy soil microbiome. On the other hand, as photosynthetic microorganisms, microalgae harness sunlight to convert carbon dioxide (CO2) into organic matter through photosynthesis. This ability allows them to sequester carbon and contribute to sustainable agriculture by reducing greenhouse gas emissions. The present work provides an overview of the potential of microalgae as biofertilizers, highlighting their unique characteristics, benefits, and main limitations for effective implementation in agriculturally sustainable practices.