Activity Research Of Gracilaria Lemaneiformis-degradation Products And Cloning Expression Of Sulfatase Gene In Degrading Bacteria Flammeovirga Pacifica

In this paper, we studied a strain isolated from sediment samples of the west Pacific Ocean—Flammeovirga pacifica which can degrade asparagus to produce oligosaccharides. We found more than80possible sulfatase enzyme genes from the complete genome sequence of this strain.we blasted these genes in NCBI and choose the highest homology gene Ary423to clone and express. It encoded a protein of511amino acids with a calculated molecular mass of57.2kDa.The protein contained a typocal N-terminal signal peptide of21amino acid residues, We cloned it into E.coli BL21. Inducted by IPTG and expressed, after optimization, His fusion protein was purified under nondenaturing conditions. The enzyme activity testing showed that it having a the PNPS degradation activity. And degradation of the the asparagus polysaccharide, stripped of crude polysaccharide sulfate. The Optimum temperature of recombinant strain is40℃, the optimum pH is8-9. Mg2+could activate the enzyme. Fe3+, Cu2+can inhibit the enzyme activity. Mercaptoethanol, urea,10mmol/L EDTA has a certain inhibition.Using the oligosaccharides degradation from the asparagus directly by this strain, we studied from antibacterial, growth-promoting, antioxidation, and fruits preservative effect. By electron microscopic examination, we found that80ppm oligosaccharide fermentation broth can significantly promote the growth of duck weed, stomatal becomes large, tissue cells get larger compared with the control. In inhibiting the growth of microorganisms, we selected several common fungus (Aspergillus niger, Paecilomyces variotii Verticillium dahliae, Sclerotinia sclero-tiorum) and bacteriums (Escherichia coli, Staphylococcus aureus, Vibrio alginoly-ticus, Vibrio parahaemolyticus),we found that oligosaccharide can inhibite the Vibrio parahaemolyticus. Antibacterial rate of1.6mg/ml oligosaccharide can reach50%. But it had no inhibitory effect on other fungis and bacteria. Specific inhibitory mechanism remains to be further studied. On antioxidant activity, we made three models: resistance of Drosophila to paraquat, pyrogallol autoxida-tion, DPPH radical scavenging. The result showed that Oligosaccharides can significantly improve the life of the female fruit flies, slowing the rate of autoxi-dation of pyrogallol, effectively clear the DPPH radical. Strawberry Preservation, oligosaccharides can reduce moisture loss and reduce the storage straw-berry Vc loss. Oligosaccharide sample was post-threatened by freeze drying, spray drying, active carbon and tested the difference each other by ion-chromato graphic analyzer. In order to provide the basis for the preservation of oligosaccharides.