Production and characterization of cellulose by Glucanoacetobacter hansenii in medium containing glucose or mannitol

ABSTRACT

The cellulose, polysaccharide of vegetable origin, is an abundant biopolymer found in nature and, therefore, a valuable tool for the science of materials applications in the medical, cosmetic, refinery, and other areas. As an alternative to traditional cellulose production, we have the microbial path, which results in a nanometric fiber with good mechanical properties. Among the several microorganisms that produce bacterial cellulose (BC), the one that presents very satisfactory results is the strictly aerobic and Gram-negative bacteria known as Gluconacetobacter hansenii (ATCC - 23769). This biopolymer presents enormous application potential due to its thermal, mechanical and biocompatibility properties. Many researches are being developed to optimize the productive processes of BC, resulting in greater conversions with a lower production cost. This work aimed to produce the cellulose membranes obtained in mannitol (C-MM) or Hestrin and Schramm (HS) (C-MH) medium and to characterize them through infrared spectroscopy (IR), thermogravimetric (TGA) and X-ray diffraction (XRD) analyses. The celluloses produced presented similar morphological images, but the mannitol medium had a higher yield (2.09 g. L^-1) in the BC production when compared to the Hestrin and Schramm medium (HS) (1.15 g. L^-1). In addition, the bacterial cellulose produced in medium containing mannitol presented higher crystallinity (78%) than that produced in Hestrin e Schramm (HS) (65%). Through the IR analysis, it was possible to confirm the functional groups present in the bacterial cellulose without any contaminants from the production process. Regarding the thermogravimetric analysis, the polymer formed from the mannitol medium presented higher thermal stability. Finally, the biofilms produced in the different medium had different properties, revealing that the polymeric characteristics change according to the bacterial growth medium.

Keywords
Bacterial cellulose; Glucanoacetobacter hansenii ; Mannitol; Glucose