Diversity of bacterial strains degrading hexadecane in relation to the mode of substrate uptake

Authors

  • M. Bouchez Naïtali,

    1. 1 Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, Massy cedex, and 2Division Chimie et Physico-chimie Appliquées, Institut Français du Pétrole, Rueil Malmaison cedex, France
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  • 1 H. Rakatozafy,

    1. 1 Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, Massy cedex, and 2Division Chimie et Physico-chimie Appliquées, Institut Français du Pétrole, Rueil Malmaison cedex, France
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    • 1 R. Marchal,

      1. 1 Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, Massy cedex, and 2Division Chimie et Physico-chimie Appliquées, Institut Français du Pétrole, Rueil Malmaison cedex, France
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    • 2 J. Y. Leveau,

      1. 1 Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, Massy cedex, and 2Division Chimie et Physico-chimie Appliquées, Institut Français du Pétrole, Rueil Malmaison cedex, France
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    • and 1 J. P. Vandecasteele 2

      1. 1 Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, Massy cedex, and 2Division Chimie et Physico-chimie Appliquées, Institut Français du Pétrole, Rueil Malmaison cedex, France
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    Dr M. Bouchez-Naïtali, Ecole Nationale Supérieure des Industries Agro-alimentaires, Laboratoire de Microbiologie Industrielle, 1, avenue des Olympiades, 91744 Massy cedex, France (e-mail: naitali@ensia.inra.fr).

    Abstract

    The relative distribution of the modes of hydrocarbon uptake, used by bacteria of the environment for the degradation of long chain alkanes, has been evaluated. The first mode of uptake, direct interfacial accession, involves contact of cells with hydrocarbon droplets. In the second mode, biosurfactant mediated transfer, cell contact takes place with hydrocarbons emulsified or solubilized by biosurfactants. Sixty one strains growing on hexadecane were isolated from polluted and non polluted soils and identified. The majority (61%) belonged to the Corynebacterium Mycobacterium Nocardia group. Criteria selected for characterizing hexadecane uptake were cell hydrophobicity, interfacial and surface tensions and production of glycolipidic extracellular biosurfactants. These properties were determined in flask cultures on an insoluble (hexadecane) and on a soluble (glycerol or succinate) carbon source for a subset of 23 representative strains. Exclusive direct interfacial uptake was utilized by 47% of studied strains. A large proportion of strains (53%) produced biosurfactants. The data on cellular hydrophobicity suggested the existence of two distinct alkane transfer mechanisms in this group. Accordingly, tentative assignments of biosurfactant mediated micellar transfer were made for 11% of the isolated strains, and of biosurfactant enhanced interfacial uptake for 42%.

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