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Diversity of bacterial strains degrading hexadecane in relation to the mode of substrate uptake
Author(s) -
Bouchez Naïtali M.,
Rakatozafy H.,
Marchal R.,
Leveau J. Y.,
Vandecasteele J. P.
Publication year - 1999
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1999.00678.x
Subject(s) - substrate (aquarium) , diversity (politics) , hexadecane , relation (database) , substrate specificity , bacteria , microbiology and biotechnology , biology , chemistry , environmental chemistry , ecology , biochemistry , genetics , enzyme , computer science , organic chemistry , sociology , database , anthropology
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%.