Font Size: a A A

Structural Characterizations Of The Extracellular Polysaccharides Produced By Three Marine Microorganisms From Different Marine Environments

Posted on:2016-11-06Degree:MasterType:Thesis
Country:ChinaCandidate:C L ChenFull Text:PDF
GTID:2180330473458658Subject:Pharmaceutical engineering
Abstract/Summary:PDF Full Text Request
Marine microorganisms are important marine biological resources. The extracellular polysaccharides from marine microorganisms have novel structures and functions distinguishing from the polysaccharides from terrestrial organisms, due to marine microorganisms grow in saline coastal sediment habitats with the lack of oxygen and nutrition, high pressure and low temperature. In the paper, the chemical compositions and structural characterizations of the extracellular polysaccharides isolated from the fermented broth of three different marine microorganisms were investigated. The results were as follows:1. Crude extracellular polysaccharide LC was obtained from the fermented broth of the marine sponge-associated fungus Aspergillus versicolor fj-112 from Xisha, and purified by Q-Sepharose Fast Flow column chromatography and Sephacryl S-100 column chromatography. Two extracellular polysaccharides LC-1-p and LC-2-p were obtained. LC-1-p and LC-2-p appeared as single and symmetrical peak in the HPGPC chromatograms, respectively, indicating they could be purified polysaccharides. The molecular weights of LC-1-p and LC-2-p were estimated to be about 5 kDa and 7 kDa, respectively. IR, methylation and NMR analyses indicated that LC-1-p mainly consisted of â†'2)Manp(1â†'residues with small amounts of â†'1)-Galp(4â†', â†'1)-Manp(6â†' and â†'2,3)Manp(1â†'residues. The results suggested that the extracellular polysaccharide LC-1-p was a branched galactomannan distinguishing from other extracellular polysaccharides from marine microorganisms.2. Crude extracellular polysaccharide, LD was obtained from the fermented broth of the marine sponge-associated actinomycetes Streptomyces sp. HDN-10-293 from Xisha, and further purified by Q-Sepharose Fast Flow column and Sephacryl S-100 column. An extracellular polysaccharide LD-2-p was obtained. LD-2-p appeared as a single and symmetrical peak in the HPGPC chromatogram, indicating that it could be homogeneous polysaccharides. The molecular weight of LD-2-p was estimated to be about 13 kDa Reversed-phase HPLC analysis showed that LD-2-p was mainly composed of galactose with a minor amount of glucose. IR, methylation and NMR analyses indicated that LD-2-p mainly consisted of â†'3)Galp(1â†' with small amount of Galp(1â†' and â†'6)Glcp(1â†'residues. The results suggested that the extracellular polysaccharide LD-2-p was a linear glucogalactan.3. Crude extracellular polysaccharide LG was obtained from the fermented broth of the marine fungus Aspergillus sp. ZZZ-115 from the Indian Ocean using filtration, concentration, dialysis and ethanol precipitation, and further purified by Q-Sepharose Fast Flow column and Sephacryl S-100. Two extracellular polysaccharides, named LG-3-D1 and LG-3-D2 were obtained. LG-3-D1 and LG-3-D2 appeared as a single and symmetrical peak in the HPGPC chromatograms, respectively, indicating that they could be homogeneous polysaccharides. The molecular weight of LG-3-D1 and LG-3-D2 were estimated to be about 23 kDa and 16 kDa. The monosaccharide compositions of LG-3-D1 and LG-3-D2 were similar, and they were mainly composed of Man and Gal in a molar ratio of 1.6:1.0. IR, methylation and NMR analyses indicated that LG-3-D2 mainly consisted of â†'2)Manp(1â†' with small amounts of Galp(1â†',â†'4)Galp(1â†',â†'6)Manp(1â†' and â†'2,3)Manp(1â†' residues. The results suggested that the extracellular polysaccharide LG-3-D2 was a branched galactomannan.The research enriched the data resources of "marine sugar library", and laid a foundation for the development and utilization of marine extracellular polysaccharides.
Keywords/Search Tags:marine microorganism, extracellular polysaccharide, purification, structural characterization
PDF Full Text Request
Related items