Produção por processamento físico e caracterização de nanomateriais funcionais a partir de celulose bacteriana biossintetizada por SCOBY para aplicações biotecnológicas

Abstract

Bacterial cellulose (BC) is a high-purity natural biopolymer produced by acetic acid bacteria, commonly found in symbiotic consortia with yeasts (SCOBY – Symbiotic Culture of Bacteria and Yeast), and is recognized for its unique structural properties and potential for biotechnological applications. This study aimed to obtain and characterize materials derived from nanocellulose using BC produced via static fermentation of sweetened green tea, followed by alkaline purification (NaOH 1 mol L⁻¹) and oxidative bleaching with sodium hypochlorite. The purified BC was subjected to intensified physical processing, including mechanical disintegration (ultraturrax), ultrasonication, and spray drying, with the objective of producing a functional powdered material. Characterization was performed using Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Spectroscopic analyses confirmed the preservation of the main chemical bonds of cellulose, with no evidence of noncellulosic compounds. XRD analysis revealed an atypical diffraction pattern, suggesting structural reorganization with semicrystalline characteristics induced by physical processing. SEM analysis showed the formation of micrometric aggregates with a collapsed lamellar morphology, indicating loss of the original nanofibrillar organization and reaggregation of the structures after drying. These results indicate that, although BC initially presents a nanofibrillar structure, the applied physical processing led to partial loss of nanoscale individualization and the formation of micrometric aggregates. TGA results exhibited a thermal degradation profile typical of cellulosic materials, with events associated with moisture loss, polymer chain decomposition, and formation of carbonaceous residues. Overall, the findings demonstrate that the applied physical processing significantly altered the structural organization of BC, resulting in a reorganized material with functional potential for applications in solid formulations, controlled release systems, and bioinputs. The proposed approach represents a sustainable alternative for valorizing fermentation-derived biomass, contributing to the development of materials relevant to the bioeconomy.