Abstract
<jats:p>The increasing demand for food production has intensified the use of chemical fertilizers, raising concerns about their environmental impact. Plant Growth-Promoting Bacteria (PGPB) have emerged as a sustainable alternative; however, many studies are conducted under highly controlled conditions which do not accurately represent real agricultural systems. This study evaluated the effect of microbial consortia comprising of Azospirillum brasilense, Pseudomonas putida, Bacillus sp., and Mycobacterium sp. on plant growth under contrasting substrate conditions (commercial substrate and greenhouse soil). Their biostimulant potential was assessed in Zea mays (blue maize), Brassica oleracea (broccoli), and Solanum lycopersicum (tomato). The assessment included measurements of root and shoot elongation as well as dry biomass. The results demonstrated that microbial consortia significantly (p=0.01) improved plant growth compared to the control across all species. Among the treatments, the consortium Pseudomonas putida + Bacillus sp. had the best results by presenting significantly (p=0.01) higher values in root length, stem growth, and dry weight in both substrate types. Additionally, consortia containing Mycobacterium sp. demonstrated enhanced performance in greenhouse soil, particularly in biomass accumulation for Zea mays and Brassica oleracea. These results highlight the importance of selecting appropriate microbial combinations and validating their performance in environments that reflect practical agricultural conditions.</jats:p>