ENVIRONMENTAL MICROBIOLOGY The Marine Isolate Novosphingobium sp. PP1Y Shows Specific Adaptation to Use the Aromatic Fraction of Fuels as the Sole Carbon and Energy Source Eugenio Notomista & Francesca Pennacchio & Valeria Cafaro & Giovanni Smaldone & Viviana Izzo & Luca Troncone & Mario Varcamonti & Alberto Di Donato Received: 30 July 2010 / Accepted: 2 December 2010 / Published online: 22 January 2011 # Springer Science+Business Media, LLC 2011 Abstract Novosphingobium sp. PP1Y, isolated from a surface seawater sample collected from a closed bay in the harbour of Pozzuoli (Naples, Italy), uses fuels as its sole carbon and energy source. Like some other Sphingomo- nads, this strain can grow as either planktonic free cells or sessile-aggregated flocks. In addition, this strain was found to grow as biofilm on several types of solid and liquid hydrophobic surfaces including polystyrene, polypropylene and diesel oil. Strain PP1Y is not able to grow on pure alkanes or alkane mixtures but is able to grow on a surprisingly wide range of aromatic compounds including mono, bi, tri and tetracyclic aromatic hydrocarbons and heterocyclic compounds. During growth on diesel oil, the organic layer is emulsified resulting in the formation of small biofilm-coated drops, whereas during growth on aromatic hydrocarbons dissolved in paraffin the oil layer is emulsified but the drops are coated only if the mixtures contain selected aromatic compounds, like pyrene, propyl- benzene, tetrahydronaphthalene and heterocyclic com- pounds. These peculiar characteristics suggest strain PP1Y has adapted to efficiently grow at the water/fuel interface using the aromatic fraction of fuels as the sole carbon and energy source. Introduction Aromatic compounds are among the most widespread and hazardous pollutants. Several polycyclic aromatic hydro- carbons (PAH), like naphthalene and phenanthrene, are very toxic to aquatic organisms [5, 23], whereas benzene, chrysene, benzo[a]anthracene, benzo[a]pyrene and aromat- ic amines are carcinogenic and represent a direct risk for human health [1, 33]. Coal, petroleum and their derivatives are the main sources of aromatic compounds released into the environment. Depending on the source, aromatic hydrocarbons may comprise 20–40% of petroleum [12, 20, 42]. Gasoline may contain up to 25% and 10% mono- and polycyclic aromatic hydrocarbons, respectively [30], while diesel oil may contain up to 20% PAHs and only 5–6% alkylbenzenes [21]. The aromatic fractions of these fuels are extremely complex and are often comprised of (poly)alkyl-benzenes, PAHs, (poly)alkyl-PAHs, naph- thenes (i.e. polycyclic compounds with fused aromatic and saturated rings) and heterocyclic compounds containing nitrogen, sulphur or oxygen. The so-called obligate hydrocarbonoclastic bacteria (OHCB), like Alkanivorax, Marinobacter and Oleispira, are among the most effective oil degraders [32, 44]. Electronic supplementary material The online version of this article (doi:10.1007/s00248-010-9786-3) contains supplementary material, which is available to authorized users. E. Notomista (*) : F. Pennacchio : V. Cafaro : G. Smaldone : V. Izzo : L. Troncone : M. Varcamonti : A. Di Donato Dipartimento di Biologia Strutturale e Funzionale, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cinthia 4, 80126 Naples, Italy e-mail: notomist@unina.it E. Notomista : V. Izzo Facoltà di Scienze Biotecnologiche, Università di Napoli Federico II, Naples, Italy A. Di Donato CEINGE-Biotecnologie Avanzate S.c.ar.l., Naples, Italy Microb Ecol (2011) 61:582–594 DOI 10.1007/s00248-010-9786-3