Biological inoculant for promotion of growth in forest species and method for obtaining the same

An immobilizing process for obtaining a biological inoculant that stimulates plant growth characterized in that it comprises the steps of:

• a) forming a support medium from teak wood sawdust at a size between 400-1000 μm subjected to a heat treatment such that the sawdust burns homogeneously, does not generate ash, possesses a bulk density of 0.1 g/l to 0.2 g/l, where its color is between the 7.5R2/4 and 10YR2/4 categories with particles present in 10Y1/2 color according to the Munsell color chart and having the following composition:
• i) total organic carbon from 20% to 40%,
• ii) total nitrogen between 0.1% and 0.5%,
• iii) carbon/nitrogen >90,
• iv) cation exchange capacity >20 meq/100 g,
• v) calcium between 8 and 15 meq/100 g,
• vi) magnesium 6 to 12 meq/100 g,
• vii) potassium 4 to 8 meq/100 g,
• viii) sodium 1 to 5 meq/100 g,
• ix) available phosphorus between 400 and 750 ppm;
• b) culturing one or more plant growth promoting strains of the negative Gram group of bacteria in a fermentation system until the end of their exponential or logarithmic phase, when they reach maximum cell biomass production and generate secondary metabolites that increase the solubilization of nutrients in the substrates for sowing plants and increase the plant growth, wherein the secondary metabolites are acids and compounds regulating plant growth, removing the supernatant and re-suspending it in 0.85% concentration saline to a final cell concentration of 1012 CFU/mL;
• c) mixing each solution resulting from step b) with the teak sawdust support obtained in step a) in proportion of inoculum:
• support from 2:5 to 2:7;
• and
• d) cultivating the mixture obtained in the step c) for a period of time between 24 and 72 hours at a temperature between 25° C. and 42° C. and optionally including excipients, to obtain the biological inoculant.