Biosurfactant activity, heavy metal tolerance and characterization of Joostella strain A8 from the Mediterranean polychaete Megalomma claparedei (Gravier, 1906) Carmen Rizzo 1 • Luigi Michaud 1 • Marco Graziano 1 • Emilio De Domenico 1 • Christoph Syldatk 2 • Rudolf Hausmann 3 • Angelina Lo Giudice 1,4 Accepted: 28 May 2015 / Published online: 10 June 2015 Ó Springer Science+Business Media New York 2015 Abstract The effect of heavy metals on the activity of biosurfactants produced by Joostella strain A8 from the polychaete Megalomma claparedei was investigated. Bio- surfactant 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 bio- surfactants was then evaluated in the presence of heavy metals at different concentrations in liquid cultures that were incubated under optimal conditions for biosurfactant activ- ity. 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. Keywords Biosurfactant activity Á Filter-feeding organisms Á Heavy metal tolerance Introduction Heavy metals (HM) have been reported as major envi- ronmental pollutants. They are introduced naturally through the weathering of rocks as well as from a variety of human activities (e.g. mining and industrial processes) that have metal residues in their waste streams. Once in the water bodies, these contaminants cannot be easily dis- persed, thus becoming localized and accumulated in sedi- ments, which are the natural collectors of pollutants. However, available HM in sediment could be reintroduced to water or be uptake by plants and benthic organisms (Amoozadeh et al. 2014). Among these latter, sedentary filter feeders, filtering huge amount of seawater and being strictly in contact with the sedimentary compartment, potentially accumulate different kinds of contaminants (including HM), both in the soluble and in the particulate phases, from the environment (Selvin et al. 2009). Microbial biosurfactants, as good metal complexing agents, have been reported to be effective in the remedia- tion of heavy metal contaminated environments (Singh and Cameotra 2004) thanks to their biodegradability and low toxicity compared to synthetic surfactants, in addition to environmental compatibility and stability at extremes of pH, salinity and temperature (Kiran et al. 2010). Most biosurfactants of marine origin reported till dates are obtained from microorganisms isolated from contaminated seawater and sediment. However, we have recently high- lighted the potential of sabellids (Polychaeta: Annelida) as a novel source of BS-producing bacteria, with most of them that belonged to genera whose ability to produce & Angelina Lo Giudice alogiudice@unime.it; angelina.logiudice@iamc.cnr.it 1 Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontre `s 31, 98166 Messina, Italy 2 Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany 3 Institute of Food Science and Biotechnology, Section Bioprocess Engineering, University of Hohenheim, 70593 Stuttgart, Germany 4 Institute for the Coastal Marine Environment, National Research Council (IAMC-CNR), Spianata San Raineri 86, 98122 Messina, Italy 123 Ecotoxicology (2015) 24:1294–1304 DOI 10.1007/s10646-015-1504-y