High Sporulation of Bacillus XT13, XT14, and XT17 in Submerged medium for Drought-Stress Applications

Latin America faces increasing challenges due to climate change, with drought and desertification. In this context, AGROSAVIA selected three Bacillus strains (XT13, XT14, and XT17) with plant growth-promoting effects and potential in mitigating water-deficit stress. A culture medium for the three strains was developed by assessing 6 liquid media (Landy, DSM, GYS, Pandey, Flour Mix, and JM). Assays were performed individually in microcultures (24-well plates), with a working volume of 2 mL and 1% of inoculum. Microplates were incubated at 30°C and 150 rpm, with sampling times at 48 h and 72 h. The results showed that the Landy medium promoted the most growth of the strains evaluated, obtaining concentrations of 2.7×10⁸, 1.7×10⁷, and 6.3×10⁷ UFC/mL for vegetative cells, while obtaining spore values of 5.1×10⁸, 6.7×10⁷, and 1.0×10⁵ UFC/mL, respectively, for the strains XT13, XT1,4, and XT17 at 48 h. At 72 h, the vegetative cell results were 1.0×10⁸, 6.3×10⁶, and 4.2×10⁸ UFC/mL, and the spore counts were 7.1×10⁸, 2.1×10⁷, and 4.3×10⁸ UFC/mL. The results demonstrate the sporulation potential of Landy medium, with the highest productivity achieved at 72 h of fermentation, demonstrating its technical feasibility for obtaining a bioproduct based on the strains evaluated.