Development of Functional Bionanocomposites Using Cyanobacterial Polysaccharides

Abstract

Cyanobacteria are regarded as very eco-friendly microreactors for the production of various biomolecules such as polysaccharides by fixing not only carbon but also nitrogen in water. Cyanobacterial polysaccharides having various functional groups such as hydroxyls, carboxyls, sulfates, etc. have the ability to interact with metals or inorganics, to create bionanocomposites. Sacran, a supergiant cyanobacterial anionic polysaccharide extracted from the extracellular matrix of Aphanothece sacrum which is mass-cultivated in freshwater, is mainly used to create functional bionanocomposites. Gel-type bionanocomposites of sacran with various metal cations are formed and showed photoresponsive functions. Metal recovery is performed from the sacran bionanocomposite gels. Sacran chains are complexed with multi-wall carbon nanotubes (MWCNT) to give viscose dispersion from which MWCNT bionanocomposites can be collected by electrophoresis. The MWCNT/sacran dispersion retains the capability of adsorbing various metal ions to form hardened hydrogel beads. Finally, natural inorganic sepiolite can be used for sacran bionanocomposites which show an efficient neodymium ion adsorption ability. Thus, cyanobacterial polysaccharides are useful for preparing eco-friendly and functional bionanocomposites with various hard materials.

Exopolysaccharides from Cyanobacteria: Strategies for Bioprocess Development

“…Additional types of monosaccharides such as N-acetyl glucosamine, 2,3-O-methyl rhamnose, 3-O-methyl rhamnose, 4-O-methyl rhamnose, and 3-O-methyl glucose are also reported [29,30]. At the macromolecular scale, these polymers are characterized by high molecular weight, which can range from kDa to MDa, whereas more than 75% of those characterized are heteropolymers [6]. The physico-chemical role of these building blocks is extremely rich.…”

“…Eco-friendlier cellular factories such as phototrophic organisms have been highlighted to raise the sustainability of the whole bioprocess [5]. Cyanobacteria can be light-powered, consume inorganic carbon to produce oxygen, and even fix nitrogen under diazotrophic conditions [6]. They are widely known for being rich in protein and a prolific source of secondary metabolites [7].…”

“…A rule of thumb EPS from cyanobacteria are heteropolysaccharides of anionic nature due to uronic acids and are soaked in neutral sugars. In a nutshell, cyanobacterial EPS holds higher complexity among microbes [6]. Physico-chemical properties of cyanobacterial EPS have shown promising performances suitable for the industry as gums, bioflocculants, soil conditioners, biolubrificants, and biosorbents [11][12][13].…”

The Use of Megamolecular Polysaccharide Sacran in Food and Biomedical Applications

“…This indicates that the solution is not contaminated by proteins, nucleic acids, chromophores, and/or other chemicals that have UV-Vis absorption. The yield of sacran extraction is very high (i.e., 70% of dry A. sacrum ) [ 40 , 41 , 42 ].…”

Sacran, a High-molecular Weight Polysaccharide Inhibits Renal Injury and Oxidative Stress in Chronic Renal Failure Model Rats

“…It is noteworthy that another type of ampholytic polysaccharide, Sacran (Figure 1) is extracted from the Japanese indigenous Cyanobacterium Aphanothece sacrum, which is mass-aquacultured in rivers. This polysaccharide has a high ionic concentration, and contains a jelly-like Extracellular Matrix (ECM) with a high water content (97.5%) [15][16][17]. Sacran is a hetero polysaccharide that is made up of various sugar residues, including glucose, galactose, mannose, xylose, rhamnose, fucose, galacturonic acid and glucuronic acid, as well as traces of alanine, galactosamine and muramic acid; 11% of the monosaccharides contain a sulfate group and 22% contain a carboxyl group.…”