Bacterial cellulose produced by Medusomyces gisevii on glucose and sucrose: biosynthesis and structural properties

Abstract

In this work, the effects of carbon sources and culture media on the production and structural properties of bacterial cellulose (BC) synthesized by Medusomyces gisevii have been studied. The culture medium was composed of different initial concentrations of glucose or sucrose dissolved in 0.4% extract of plain green tea. Parameters of the culture media (titratable acidity, substrate conversion degree etc.) were monitored daily for 20 days of cultivation. The BC pellicles produced on different carbon sources were characterized in terms of biomass yield, crystallinity and morphology by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and x-ray diffraction (XRD). Our results showed that Medusomyces gisevii had higher BC yields in media with sugar concentrations close to 10g∙L-1 after a 18–20 days incubation period. Glucose in general lead to a higher BC yield (173g∙L-1) compared to sucrose (163.5g∙L-1). The BC crystallinity degree and surface roughness were higher in the samples synthetized from sucrose. Obtained FE-SEM micrographs show that the BC pellicles synthesized in the sucrose media contained densely packed tangles of cellulose fibrils whereas the BC produced in the glucose media displayed rather linear geometry of the BC fibrils without noticeable aggregates.

Design and Modeling of a Biotechnological Nanofiltration Module Using Bacterial Cellulose Membranes for the Separation of Oily Mixtures

“…In contrast, the images taken at the highest magnification (160 KX) (Figure 8E,F) reveal that the fibers have an approximate diameter of 84 nm and do not follow a pattern of organization but are interlaced [64], which enables greater molecule retention capacity [63], especially for large carbon chains, as is the case of oil, whether in free form, dispersed or in an emulsion [5]. The SEM analysis demonstrated that the purification process and rinsing after the removal of the membranes from the metabolic broth were effective at removing any microorganisms that may be retained among the fibrils of the membrane, as no bacteria were seen in any of the images.…”

“…In contrast, the images taken at the highest magnification (160 KX) (Figure 8E,F) reveal that the fibers have an approximate diameter of 84 nm and do not follow a pattern of organization but are interlaced [64], which enables greater molecule retention capacity [63], especially for large carbon chains, as is the case of oil, whether in free form, dispersed or in an emulsion [5].…”