Estudo da atividade de floculação de Azospirillum brasilense em processo fermentativo industrial

Abstract

With a fundamental importance in the maintenance and conservation of the environment, microbiology has been shown to be efficient in its application in agriculture. The use of rhizobacteria as biofertilizers to enhance and improve the quality of some cultivars has been the subject of studies and research. Azospirillum brasilense has the ability to delay the production of phytohormones. The production of this microorganism on an industrial scale generates the formation of floccules, which makes it difficult to accurately obtain results during quality control analyses. formation of flocs, which ends up preventing quality control analyzes with more precision, even though this capacity is of paramount importance in its application in the soil. The aim of this study was to evaluate the possible causes of flocculation activity in Azospirillum brasilense. The research was developed in the Fertibio do Brasil inoculant industry, where analyzes of colony morphology were analyzed through cell growth, biochemical profile through 8 tests adapted from the literature, carbon evaluation and follow-up in the culture medium obtained from the analyzed relationship C/N, surfactant supplementation tests to delay flocculation, namely: Tween 20, Tween 80 and Lauryl Ether Sulfate, deflocculation tests using urea according to the literature, flocculation induction test by changing pH, temperature and absorption and viability tests performing a monthly serial dilution of a fermented microorganism under specific conditions. From the results obtained, according to the analysis of cell and colony morphology, define Azospirillum brasilense Ab-V5 and Ab-V6 as a Gram-negative bacillus, short and curved, with flattened colonies, entire and circular edges. The other tests involving changing sources of agitation and supplementation of the culture medium with surfactants resulted in a flocculation delay of up to 96 h, the analyzes for deflocculation did not obtain the expected results regarding the total deflocculation of the microorganism, whereas the induction test obtained a period up to 28 h for the start of flocculation, all data obtained were statistically evaluated using the ANOVA and Tukey test.