Encapsulation of Azotobacter vinelandii ATCC 12837 in Alginate-Na Beads as a Tomato Seedling Inoculant

Encapsulation is an immobilization method characterized by restricting microbial cells to a delimited area while preserving their metabolic viability. This technique represents an alternative to improve the adaptive capacity of bacteria in the face of interactions with native microorganisms and environmental factors that limit their inoculation. This study aimed to evaluate the effect of Azotobacter vinelandii ATCC 12837 encapsulated in alginate-Na beads as an inoculant of tomato (Solanum Lycopersicum L) seedlings. Two inoculation treatments were carried out: liquid and encapsulated, and the control without microorganisms. Physiological variables, microbial viability, and the presence of A. vinelandii were determined by qPCR. Inoculation with A. vinelandii in liquid and encapsulated form favored seedling growth. Plants with the encapsulated inoculum significantly increased germination percentage (20%), stem diameter (38%), seedling height (34%), root length (69%), NO₃ concentration (41%), and Na (30%); compared to the control. Encapsulation of A. vinelandii in alginate-Na macrocapsules allowed its establishment in the rhizosphere and was corroborated by viable count and molecular methods. The viability of the bacteria was maintained for 28 days using both inoculation methods, and not detected in the control treatment.