| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1489-2 | ||||
Resumo:A group of microorganisms that stands out for their application as bioinoculants are plant growth-promoting rhizobacteria (PGPRs), frequently isolated from the rhizosphere of plants. These bacteria are capable of stimulating plant growth through direct and indirect mechanisms. Currently, there is a growing interest in the development of formulations that allow the controlled release of these bioinoculants into the soil. This approach offers the significant advantage of preserving microorganisms for an extended period, thus amplifying the beneficial effects on plant growth and protection, as well as extending the shelf life of the biological product. The central challenge lies in designing capsules that can house these bacteria without inactivating them. The objective of this work was to evaluate the potential use of carboxymethyl cellulose (CMC), chitosan and clay as encapsulating materials for a strain of Bacillus sp. which demonstrates the ability to promote plant growth. The biocapsules were prepared from a microbial suspension containing 10^8 CFU/mL, varying the CMC concentrations from 0.5% to 0.75%. This suspension was subjected to the extrusion process under constant stirring in a chitosan solution with concentrations ranging from 2% to 4%. For a period of one hour at room temperature, the biocapsules were kept under constant agitation. After determining the best combination of CMC and chitosan concentrations, tests were carried out by adding different concentrations of clay (1% to 2%) to the encapsulation solution. The resulting biocapsules were characterized using optical microscopy, measurement of size and average weight, encapsulation efficiency, degree of swelling of the biocapsule and release of Bacillus sp. cells. immobilized over time. The most effective concentrations were 1% CMC, 0.2% chitosan and 1.5% clay, resulting in biocapsules with a uniform structure and capable of individualization. The encapsulation efficiency was 100%. The average diameter of the capsules was 3.5 mm, with an average weight of 27.6 mg. The degree of swelling reached 3783%, with the biocapsules reaching equilibrium swelling after 2 days. The release of cells in aqueous media was evaluated for up to 6 days, resulting in a concentration of 9x10^4 CFU/mL at the end of this period. The results of this study highlight the potential of combining CMC, chitosan and clay as encapsulating materials for PGPRs, with high efficiency, uniform size and controlled release capacity from bacterial cells, offering interesting perspectives for practical application in agriculture. Palavras-chave: Biocapsules, Bioinputs, Sustainable Agriculture, PGPRs Agência de fomento:UTFPR | |||||