Characterization of extracellular polymeric substances produced by micro-algae Dunaliella salina

Discipline of Marine Biotechnology and Ecology, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364021, Gujarat, India
Carbohydrate Polymers (Impact Factor: 4.07). 01/2011; 83(2):852-857. DOI: 10.1016/j.carbpol.2010.08.067


Extracellular polymeric substances comprised of average molecule size 1264.354 μm, exhibited characteristic diffraction peaks at 6.025°, 9.675°, 22.775° and 28.475° with d-spacing 14.74755, 9.36297, 3.88747 and 3.11512 Å, respectively. EDX confirms the presence of sulphate (2.7%) and 1H NMR reveals uronic acid, primary amine, aromatic-compounds, halides, aliphatic alkyl and sulfides. EPSs were thermostable upto 270 °C with CIxrd 0.12 and CIDSC 0.18. The dynamic viscosity is significantly high at pH 3.0 and decreases concomitantly with shear rate, confirming pseudoplastic rheological property. MALDI TOF–TOF represents a series of masses in linear mode corresponding to mass of pentose and hexose with ions. The positive ion reflector mode exhibited low mass peaks (m/z) corresponding to oligosaccharide and higher peaks for polysaccharide consist of different ratio of pentose and hexose associated with ions. EPSs allow further exploration of D. salina as potential EPSs producer and make it a promising candidate for biotechnological and industrial exploitation.

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Available from: Avinash Mishra, Mar 28, 2014
    • "The EPSs can be applied in food and pharmaceutical industries or in medicine as thickeners, stabilizers, gelling agents, or matrix for controlled release of drugs and active substances [10]. The composition and structure of algal polysaccharides have been studied by gas chromatography, X-ray diffraction, thermal analysis, NMR, and mass spectrometry [10] [11]. Few works have been "
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    ABSTRACT: Extracellular polysaccharides (EPSs) produced by algae can be applied in numerous branches of industry, depending on their origin and properties. In this work, the EPS produced with green microalgae Dictyosphaerium chlorelloides was studied by Fourier transformed infrared spectroscopy (FTIR) and atomic force microscopy (AFM), which enabled the characterization of its nanostructure. It was observed that the nanostructure of this exopolysaccharide self-assembly depends on its concentration. At a concentration of 1 mg/mL the EPS formed a regular and porous matrix on mica, where fibers were cumulated in bundles of 50-70 nm wide. In a more diluted concentration of 10 µg/mL single molecules created a regular network with numerous branches. An average height of molecules was in the range of 400-800 pm with occasional local increase of the skeleton height which can be a result of an interconnection of the fibers. Analysis of the FT-IR spectrum showed that the EPS has a structure of α-glucan with the dominance of the galactose and rhamnose residues.
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    • "The occurrence of sulfated polysaccharides in sea salt could have origin in the marine organisms such as seaweeds and invertebrates (Mestechkina and Shcherbukhin, 2010). However, sulfated polysaccharides were also reported in microorganisms such as microalgae, namely Dunaliella salina (Mishra et al., 2011), and halophilic bacteria (Arias et al., 2003), known to colonise saline soils, thus representing other potential sources. "
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    ABSTRACT: The present work investigates, for the first time, the presence of triacylglycerides, polysaccharides, and protein of 16 food grade sea salts. Triacylglycerides, obtained by Soxhlet extraction with n-hexane, and representing a median content of 1.5 mg/kg of dry salt, were mainly composed by palmitic (42.8 mol%), stearic (13.3), linolenic (12.5), oleic (12.0), and linoleic acid (9.1) residues. Also, a dialysis-based methodology was developed to isolate the polymeric material from sea salt in amounts to allow its characterisation. The polymeric material accounted for 144 mg/kg of dry salt, mainly composed by sulfated polysaccharides and also containing protein. Polysaccharides were rich in uronic acid residues (21 mol%), glucose (18), galactose (15), and fucose (13), whereas the protein was composed by the hydrophobic amino acids alanine (25 mol%), leucine (14), and valine (14). These biomolecules arise from the surrounding environment of saltpans. Their characterisation contributes to the pursuit of parameters of origin.
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    • "Functional groups of purified EPS were determined using Fourier transformed infrared (FTIR) spectroscopy analysis. The pellet was prepared by pressing the mixture of EPS and KBr (1:100) into a mould and the FTIR spectrum was acquired in the 4000–400 cm −1 region with a resolution of 4 cm −1 using a GX FTIR system (PerkinElmer, USA) (Kavita et al., 2013; Mishra, Kavita, & Jha, 2011). "
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