Emulsifying and metal ion binding activity of a glycoprotein exopolymer produced by Pseudoalteromonas sp. strain TG12.
In this study, we describe the isolation and characterization of a new exopolymer that exhibits high emulsifying activities against a range of oil substrates and demonstrates a differential capacity to desorb various mono-, di-, and trivalent metal species from marine sediment under nonionic and seawater ionic-strength conditions. This polymer, PE12, was produced by a new isolate, Pseudoalteromonas sp. strain TG12 (accession number EF685033), during growth in a modified Zobell's 2216 medium amended with 1% glucose. Chemical and chromatographic analysis showed it to be a high-molecular-mass (>2,000 kDa) glycoprotein composed of carbohydrate (32.3%) and protein (8.2%). PE12 was notable in that it contained xylose as the major sugar component at unusually high levels (27.7%) not previously reported for a Pseudoalteromonas exopolymer. The polymer was shown to desorb various metal species from marine sediment-a function putatively conferred by its high content of uronic acids (28.7%). Seawater ionic strength (simulated using 0.6 M NaCl), however, caused a significant reduction in PE12's ability to desorb the sediment-adsorbed metals. These results demonstrate the importance of electrolytes, a physical parameter intrinsic of seawater, in influencing the interaction of microbial exopolymers with metal ions. In summary, PE12 may represent a new class of Pseudoalteromonas exopolymer with a potential for use in biotechnological applications as an emulsifying or metal-chelating agent. In addition to the biotechnological potential of these findings, the ecological aspects of this and related bacterial exopolymers in marine environments are also discussed.
Gutierrez
Tony
T
Microbial and Molecular Biology Department, Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban PA37 1QA, United Kingdom. tony.gutierrez@sams.ac.uk
Shimmield
Tracy
T
Haidon
Cheryl
C
Black
Kenny
K
Green
David H
DH
D000596:Amino Acids / Q000032:analysis; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D045703:Emulsifying Agents / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006868:Hydrolysis; D007477:Ions / Q000378:metabolism; D008670:Metals / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D031161:Pseudoalteromonas / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology; D012965:Sodium Chloride / Q000494:pharmacology
D000596:Amino Acids; D001426:Bacterial Proteins; D045703:Emulsifying Agents; D006023:Glycoproteins; D007477:Ions; D008670:Metals; D012965:Sodium Chloride