Production and Characterization of Exopolysaccharide From Marine Moderately Halophilic Bacterium Halomonas Smyrnensis SVD Iii

Abstract

Objective: To study 1) Optimization of nutritional and environmental parameters to enhance the yield of EPS by Halomonas smyrnensis SVD III isolated from seawater, West Coast of Maharashtra, India and 2) Purification and characterization of the EPS produced. Methods:The isolate was grown in Sehgal and Gibbons (SG) medium broth supplemented with 3% glucose, at 37 °C, 120 rpm for 7 d. Optimization of different parameters was carried out with one factor at a time approach. EPS was isolated from cell-free supernatant of the culture broth by centrifugation and precipitation using chilled ethanol, after removal of proteins by trichloroacetic acid (TCA) treatment. Characterization of the purified EPS was carried out with respect to fourier-transform infrared (FTIR) spectrum, 1 H nuclear magnetic resonance (NMR) spectrum and mass spectrometry (MS) analysis.Results: Two-fold increase in the yield of EPS (23 g/l) by the selected isolate was obtained by using culture conditions as 10% inoculum size having cell density of 10 7 cells/ml, pH 6, incubation temperature 45 °C, 3% carbohydrate, 0.5% yeast extract as nitrogen source, 20% salt concentration and 7 d of incubation period. Characterization of the purified EPS suggested the presence of dominated glycosidic linkages and heptasaccharide nature of the molecule. As the present strain is halophilic, 20% NaCl was found to be optimum. Conclusion:Optimization studies resulted in two-fold increase in the yield of EPS which is of heptasaccharide nature.

Metabolic potential of the moderate halophile Yangia sp. ND199 for co‐production of polyhydroxyalkanoates and exopolysaccharides

“…While carbon and nitrogen sources and the concentrations of salts had significant effects on the production of polymers in Yangia , the amount of EPS produced so far (60–70 mg/g CDW) was low compared with that reported for other halophiles such as Halomonas alkaliantarctica, Halomonas eurihalina , Halomonas maura, Halomonas xianhensis , H. smyrnensis, and Hfx. mediterranei (Biswas & Paul, 2017a,b; Deshmukh et al, 2017; Sarilmiser et al, 2015; Cui et al, 2017b), but in the same range as that for Halomonas ventosae (Mata et al, 2006). Further studies are needed to determine the conditions for increasing the production of EPS, its characteristics, and its potential applications.…”

“…No absorption peaks around the region of 1700–1770 cm −1 attributed to C=O stretching of carbonyls in esters were observed (Kielak et al, 2017). The peak in the region of 1644 cm −1 would represent the absorption band of carboxylic groups, suggesting the presence of acidic sugars (Deshmukh et al, 2017; Kielak et al, 2017), and similarly, the peak at 1219 cm −1 observed in some samples could be attributed to C‐O stretching in ether or alcohol groups (Gu et al, 2017; Kanamarlapudi & Muddada, 2017). The peak at 1051 cm −1 indicates a possible α (1→6) glucosidic bond with certain flexibility (Gu et al, 2017), while the absorption band at 978 cm −1 suggests the vibrations of the glycosidic bonds C‐O‐C and the peak in the region of 840–860 cm ‐1 are characteristic of α‐D‐glucan (Kanamarlapudi & Muddada, 2017).…”

“…No absorption peaks around the region of 1700-1770 cm −1 attributed to C=O stretching of carbonyls in esters were observed (Kielak et al, 2017). The peak in the region of 1644 cm −1 would represent the absorption band of carboxylic groups, suggesting the presence of acidic sugars (Deshmukh et al, 2017;Kielak et al, 2017), and similarly, the peak at 1219 cm −1 observed in some samples could be attributed…”

“…Halomonas xianhensis, H. smyrnensis, and Hfx. mediterranei (Biswas & Paul, 2017a,b;Deshmukh et al, 2017;Sarilmiser et al, 2015;Cui et al, 2017b), but in the same range as that for Halomonas ventosae (Mata et al, 2006). Further studies are needed to determine the conditions for increasing the production of EPS, its characteristics, and its poten-…”

Characterization of Exopolysaccharides Produced by Marine Bacillus Megaterium

“…In certain scenarios, the nutritional conditions can also influence the molecular weight and the EPS osidic composition. It has been shown that a novel Alteromonas macleodii strain produces 23.4 g/ L exo polysaccharide when grown on 15% of lactose, the highest yield for marine EPS [24,25,26,27,28,29] .…”