Biossíntese de celulose bacteriana a partir de Gluconacetobacter hansenii e aplicação no desenvolvimento de biomateriais: caracterização e avaliação das propriedades

Abstract

In recent years, bacterial cellulose (BC) has been the object of much research due to its high potential for application in areas such as biomedicine or materials, as well as because its biosynthesis is environmentally friendly. The BC is characterized as a homopolymer and is differentiated from vegetable cellulose by its properties, highlighting mainly the biocompatibility and biodegradability of the materials produced. The production of BC composites with various polymers is an effective method to improve their physical, chemical and structural properties. Within this context, the objective of this work was to produce BC and apply it in the development of biomaterials, characterizing and evaluating its mechanical, barrier and morphological properties. For the production of BC, the Gluconacetobacter hansenii strain (ATCC 23769) was used, where we opted for the static fermentation process with different carbon sources (glucose, mannitol, sucrose and xylose), varying between two concentrations (25 and 50 g-L -1 ). To obtain the different formulations, montmorillonite (MMT), collagen, starch and glycerol were added to evaluate the new characteristics of the BC-based biomaterials. In the production involving the addition of MMT, the BC membranes were exposed to concentrations of 0.5, 1 and 2% of this compound. As for the additions of collagen, starch and glycerol, nine formulations were produced using the casting technique. The formulations were characterized in terms of physical and barrier properties, morphology and thermal stability. The results obtained were statistically evaluated to define how the concentration of starch and/or collagen interfered in obtaining a biomaterial with characteristics suitable for use as a biocurative. The results showed that G. hansenii presented better BC yield with the use of glucose in the concentration of 50 g.L-1 . The incorporation of MMT significantly improved the mechanical and thermal properties of the membranes, exposing extended degradation temperature and a decrease in water holding capacity and an improvement in water loss rate. As for the addition of collagen, starch and glycerol in the formulations, the water activity, solubility, moisture, thickness, water vapor permeability, weight, opacity, elongation and tensile strength were directly influenced by their composition, configuring the performance of the formulations produced in different potential applications as biocuratives. Furthermore, the scanning electron microscopy demonstrated, for all the biomaterials produced, that the addition of biopolymers to the cellulose matrix made the surface compact, which also influenced the visual aspect. Thus, the results obtained showed that the BC modified with the evaluated compounds presented interesting data for further analysis of their properties, considering their potential applications in different areas, such as the production of new technologies based on biocuratives, favoring the growth of the biomedical industry in this area.