Potencial biotecnológico de las microalgas como biofertilizantes para mitigar el estrés salino en cultivos

Abstract

Soil salinization limits global agricultural productivity by affecting growth, nutrient uptake, and crop yield. Microalgae have emerged as a sustainable biotechnological alternative due to their ability to act as biofertilizers and biostimulants. These photosynthetic microorganisms produce phytohormones, amino acids, polysaccharides, and antioxidants that promote plant growth and increase tolerance to saline stress. The objective of this scoping review is to synthesize the available evidence on the potential of microalgae as biofertilizers in crops under salinity, describing their mechanisms of action, most used species, application methods, advantages, limitations, and future perspectives. The collected evidence shows that genera such as Chlorella, Scenedesmus, Dunaliella, Arthrospira, and several cyanobacteria improve nutritional efficiency, increase antioxidant activity, promote ionic balance, and reduce oxidative damage induced by excess salts. Reported applications increase crop yields between 10% and 40%, while nitrogen-fixing cyanobacteria can contribute up to 30 kg N ha⁻¹ season⁻¹. Recent molecular studies indicate that microalgal biostimulants regulate the expression of stress-responsive genes, improve osmolyte biosynthesis, and enhance the detoxification of reactive oxygen species. However, important challenges persist regarding formulation standardization, industrial scalability, and the detailed understanding of their molecular mechanisms of action.