Advances in microorganisms-based biofertilizers: Major mechanisms and applications

The rising global population and consequent reduction of land resources has led to an excessive utilization of pesticides and chemical fertilizers. With the only target of reaching the maximum productivity in conventional agricultural systems, this intensive approach has been playing a major role, both directly and indirectly, in changing the global environmental conditions. The solution can be found in sustainable agriculture, which exploits the soil microflora with the addition of the so-called Plant Growth-Promoting Bacteria (PGPB), as well as fungi and algae as biofertilizers that may perform in the soil a variety of different activities such as phosphates solubilization and nitrogen fixation. Furthermore, these microorganisms are able to produce siderophores, ammonia and hydrogen cyanide, enzymes, and phytohormones that are able to promote and regulate both plant nutrition and their growth rate. Moreover, they offer biocontrol activity against several phytopathogenic agents. As a result, biofertilizers can contribute significantly in sustainable agriculture as they are intrinsically environmentally friendly.