Use of Microalgae for the Development of Biofertilizers and Biostimulants

The use of chemical fertilizers in agriculture poses problems for the health of the soil and the environment. Biofertilizers and microalgal biostimulants emerge as an alternative to reduce these damages. This study aimed to understand how microalgae are inserted in the process of developing biofertilizers/biostimulants. A search for research articles was carried out in the Scopus and Web of Science databases and resulted in 87 relevant studies. By analyzing these articles, it was possible to structure this review to understand how microalgal biofertilizers and biostimulants act on plants. The purpose of microalgal biofertilizer is to add nutrients to the soil. The use of wastewater for microalgal growth makes the process less costly and is a treatment alternative. Culture media with higher levels of nitrogen, and microalgae that remove higher levels of nitrate result in biomass with higher levels of protein. Microalgal biostimulants are associated with compounds that can encourage plant growth. These compounds can promote enzymatic and antifungal activity, act similarly to phytohormones, and participate in the synthesis of proteins and amino acids in plants. Microalgal biofertilizers/biostimulants can be part of integrated biorefinery concepts. The integration of the production of these products with the development of biofuels increases the economic viability of these bioproducts. Even though there is a lot of talk about the use of biorefineries, there are few studies on the effective application of this concept with the use of microalgal biomass. An in-depth analysis of the mechanism of action of microalgae in the development of bioproducts for agriculture can make the process more economically advantageous and sustainable.