The structure and physical properties of glucuronic acid oligomers produced by a Gluconacetobacter hansenii strain using the waste from beer fermentation broth

Use of Anionic Polysaccharides in the Development of 3D Bioprinting Technology

Three-dimensional (3D) bioprinting technology is now one of the best ways to generate new biomaterial for potential biomedical applications. Significant progress in this field since two decades ago has pointed the way toward use of natural biopolymers such as polysaccharides. Generally, these biopolymers such as alginate possess specific reactive groups such as carboxylate able to be chemically or enzymatically functionalized to generate very interesting hydrogel structures with biomedical applications in cell generation. This present review gives an overview of the main natural anionic polysaccharides and focuses on the description of the 3D bioprinting concept with the recent development of bioprinting processes using alginate as polysaccharide.

Production and characterization of bacterial cellulose produced by Gluconacetobacter xylinus isolated from Chinese persimmon vinegar

This study aimed to characterize the structural and physico-mechanical properties of bacterial cellulose (BC) produced by Gluconoacetobacter xylinus TJU-S8 which was isolated from Chinese persimmon vinegar. Thermogravimetric analysis (TGA) showed that BC exhibited a good thermal stability. Solid-state nuclear magnetic resonance (NMR), fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) analysis revealed that BC had a typical crystalline form of the cellulose I. The BC membrane had typical characteristics such as nanodimensional network and microfibrils obtained by scanning electron microscopy (SEM). Moreover, the bacterial cellulose chitosan (BC-C) membrane and bacterial cellulose carboxymethyl chitosan (BC-CC) membrane were synthesized which showed significant inhibition against the growth of both Escherichia coli and Staphylococcus aureus. These results indicated superior properties of BC that advocated its effectiveness for various applications.

Homogenous isolation of individualized bacterial nanofibrillated cellulose by high pressure homogenization

Varying levels of high pressure homogenization (HPH) were applied to disintegrate bacterial nanofibrillated cellulose (BNFC) from bacterial cellulose (BC). HPH was considered as a simple, non-toxic and highly efficient physical method for nanofibrillated cellulose extraction. The blended BC passed through chambers at high pressures of 68, 138 and 207MPa for 30 cycles. The particle size confirmed disintegration of the BC network fibers to bundles of BNFC and the atomic force microscopy images showed the decreased diameter of individual BNFC in the range 36-67nm. Fourier transform infrared spectroscopy measurement indicated there were no change in the chemical functional groups of the BNFC compared with BC. The decreased crystallinity index and crystallite size of BNFC with increased pressure confirmed the effect of HPH on the BNFC. Nevertheless, BNFC at 207MPa had the lowest thermal stability due to having the highest surface area, which resulted in the minimum nanofiber diameter.

In situ synthesis of a bio-cellulose/titanium dioxide nanocomposite by using a cell-free system

In situ synthesis of bio-cellulose/TiO₂ nanocomposite possessing high thermo-mechanical and antibacterial properties and showing uniform distribution and slow release of nanoparticles.

Structural and physico-mechanical characterization of bio-cellulose produced by a cell-free system

This study was aimed to characterize the structural and physico-mechanical properties of bio-cellulose produced through cell-free system. Fourier transform-infrared spectrum illustrated exact matching of structural peaks with microbial cellulose, used as reference. Field-emission scanning electron microscopy revealed that fibrils of bio-cellulose were thicker and more compact than microbial cellulose. The specific positions of peaks in the X-ray diffraction and nuclear magnetic resonance spectra indicated that bio-cellulose possessed cellulose II polymorphic structure. Bio-cellulose presented superior physico-mechanical properties than microbial cellulose. The water holding capacity of bio-cellulose and microbial cellulose were found to be 188.6 ± 5.41 and 167.4 ± 4.32 times their dry-weights, respectively. Tensile strengths and degradation temperature of bio-cellulose were 17.63 MPa and 352 °C, respectively compared to 14.71 MPa and 327 °C of microbial cellulose. Overall, the results indicated successful synthesis and superior properties of bio-cellulose that advocate its effectiveness for various applications.

Production, characterization and biological features of bacterial cellulose from scum obtained during preparation of sugarcane jaggery (gur)

Bacterial cellulose (BC) has been given an ample attention due to its high potential for many industrial applications. However, the high cost of production medium has hindered the commercialization of BC. Several efforts have been made to explore cheep, raw and waste sources for BC production. The current study aims at investigating the BC production from a waste source; the scum obtained during preparation of sugarcane jaggery or gur (JS). JS was five-fold diluted with distilled water and used as culturing medium without any additional nutrients. The production of BC was monitored till 10th days of cultivation both at static and shaking culturing conditions. A maximum of 2.51 g/L and 2.13 g/L BC was produced in shaking and static cultures, respectively, after 10 days. The structure features of BC were confirmed through FTIR, XRD and SEM analysis. The chemical structure and physical appearance strongly resembled the BC produced form synthetic media. It was noteworthy that the BC produced from JS showed higher mechanical and thermal properties. The cell adhesion and proliferation capabilities of produced BC were observed that depicted definite animal cell adhesion without any considerable cytotoxicity. Besides providing an economically feasible way for BC production, the high level of physico-mechanical and biological properties insured the importance in medical fields.

Improvement of bacterial cellulose production by manipulating the metabolic pathways in which ethanol and sodium citrate involved

Nowadays, bacterial cellulose has played more and more important role as new biological material for food industry and medical and industrial products based on its unique properties. However, it is still a difficult task to improve the production of bacterial cellulose, especially a large number of byproducts are produced in the metabolic biosynthesis processes. To improve bacterial cellulose production, ethanol and sodium citrate are added into the medium during the fermentation, and the activities of key enzymes and concentration of extracellular metabolites are measured to assess the changes of the metabolic flux of the hexose monophosphate pathway (HMP), the Embden-Meyerhof-Parnas pathway (EMP), and the tricarboxylic acid cycle (TCA). Our results indicate that ethanol functions as energy source for ATP generation at the early stage of the fermentation in the HMP pathway and the supplementation of ethanol significantly reduces glycerol generation (a major byproduct). While in the EMP pathway, sodium citrate plays a key role, and its supplementation results in the byproducts (mainly acetic acid and pyruvic acid) entering the gluconeogenesis pathway for cellulose synthesis. Furthermore, by adding ethanol and sodium citrate, the main byproduct citric acid in the TCA cycle is also reduced significantly. It is concluded that bacterial cellulose production can be improved by increasing energy metabolism and reducing the formation of metabolic byproducts through the metabolic regulations of the bypasses.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2007-2008

This review is the fifth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2008. The first section of the review covers fundamental studies, fragmentation of carbohydrate ions, use of derivatives and new software developments for analysis of carbohydrate spectra. Among newer areas of method development are glycan arrays, MALDI imaging and the use of ion mobility spectrometry. The second section of the review discusses applications of MALDI MS to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N- and O-linked glycans from glycoproteins, biopharmaceuticals, glycated proteins, glycolipids, glycosides and various other natural products. There is a short section on the use of MALDI mass spectrometry for the study of enzymes involved in glycan processing and a section on the use of MALDI MS to monitor products of the chemical synthesis of carbohydrates with emphasis on carbohydrate-protein complexes and glycodendrimers. Corresponding analyses by electrospray ionization now appear to outnumber those performed by MALDI and the amount of literature makes a comprehensive review on this technique impractical. However, most of the work relating to sample preparation and glycan synthesis is equally relevant to electrospray and, consequently, those proposing analyses by electrospray should also find material in this review of interest.