title: Biosurfactant activity, heavy metal tolerance and characterization of Joostella strain A8 from the Mediterranean polychaete Megalomma claparedei (Gravier, 1906).
abstract: The effect of heavy metals on the activity of biosurfactants produced by Joostella strain A8 from the polychaete Megalomma claparedei was investigated. Biosurfactant activity was first improved by evaluating the influence of abiotic parameters. Higher E(24) indices were achieved at 25 °C in mineral salt medium supplemented with 2 % glucose, 3 % sodium chloride (w/v) and 0.1 % ammonium chloride (w/v). Considerable surface tension reduction was never recorded. Heavy metal tolerance was preliminarily assayed by plate diffusion method resulting in the order of toxicity Cd > Cu > Zn. The activity of biosurfactants was then evaluated in the presence of heavy metals at different concentrations in liquid cultures that were incubated under optimal conditions for biosurfactant activity. The production of stable emulsions resulted generally higher in the presence of metals. These findings suggest that biosurfactant production could represent a bacterial adaptive strategy to defend cells from a stress condition derived from heavy metals in the bulk environment.
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontrès 31, 98166, Messina, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Rizzo
authors.forename: Luigi
authors.initials: L
authors.lastname: Michaud
authors.forename: Marco
authors.initials: M
authors.lastname: Graziano
authors.forename: Emilio
authors.initials: E
authors.lastname: De Domenico
authors.forename: Christoph
authors.initials: C
authors.lastname: Syldatk
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hausmann
authors.forename: Angelina
authors.initials: A
authors.lastname: Lo Giudice
mesh_terms: D000818:Animals; D004361:Drug Tolerance; D041965:Flavobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D019216:Metals, Heavy / Q000633:toxicity*; D011077:Polychaeta / Q000382:microbiology*; D013501:Surface-Active Agents / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D019216:Metals, Heavy; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical