Biochemical and Microbiological Soil Effects of a Biostimulant Based on Bacillus licheniformis-Fermented Sludge

Biostimulants are substances and/or microorganisms that applied to plants or the rhizosphere in order enhance natural process improving absorption of nutrients and quality crops as well tolerance abiotic stresses. A new biostimulant was developed from sewage sludge through its fermentation with Bacillus licheniformis a plant growth-promoting bacteria (PGPB). The fermented product includes three classes components: B. biomass; enzymatic secretion said microorganism, which mainly peptidases amidases related nitrogen metabolism glucanases, carbohydrate metabolism; finally, hydrolyzed organic matter, high content protein hydrolysates. evaluated soil at biochemical (enzymatic activities) microbiological levels (metabarcoding analysis). Metabarcoding analysis revealed complex, soluble fraction containing multienzyme complex hydrolysate, induced PGPB bacteria, it detected inoculation remained active throughout study. These results show an interesting option for total valorization activated aimed obtaining products agronomic/environmental interest.