Estudo da mistura carboximetilcelulose/Lithothamnium como veículo para inoculantes rizobianos

Abstract

Inoculants can be defined as formulations composed of one or more bacterial strains that promote the plant growth. The inoculation vehicle most used is peat, however, peat is a non-renewable natural resource and it is necessary to invest in new formulations of inoculation vehicles. Formulations containing polymer blends have been gaining notoriety because it is possible to assemble specific properties of each component in a single material. Thus, the study of the effect of Lithothamnium calcareum algae with natural polymers as inoculation vehicles proved to be relevant. Lithothamnium is a seaweed, where its main characteristic is the deposition of calcium carbonate in its cell wall and has more than 20 microelements in its composition. The aim of this dissertation was investigating the action of the Lithothamnium calcareum algae in the preparation of Carboxymethylcellulose/Lithothamnium (CMC/Litho) blends and its potential use in agriculture as a bacterial inoculating vehicle. Different compositions of CMC/Lithothamnium blend containing phosphorus or not were prepared and evaluated for the ability to maintain viable cells. These samples were also submitted to the study of the rheological behavior and the characterization by Spectroscopy in the Infrared Region. Results obtained in the rheological tests showed that in the region of low frequencies Lithothamnium confers a viscous character to the blend. However, a predominance of the elastic component was observed in the region of higher frequencies, tending to the value presented by the pure CMC. Through the results obtained by Spectroscopy in the Infrared Region it was possible to verify the presence of calcium carbonate present in the algae. The cell viability results indicated that the great point of Lithothamnium content to be used was 50ppm, revealing survival values close to the peat, around 107 ucf/mL. It was verified that The CMC / Litho blend maintain the cell viability of rhizobial cells and the algae provides greater dimensional stability to the blend. Thus, the CMC/Litho blend has potential as an inoculating vehicle.