OLIVERA nelda Lila
Microbial characterization and hydrocarbon biodegradation potential of natural bilge waste microflora.
NELDA LILA OLIVERA; MARTA COMMENDATORE,; OSVALDO DELGADO,; LUIS ESTEVES, JOSÉ
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
Lugar: Berlin; Año: 2003 vol. 30 p. 542 - 542
Ship operations produce oily wastes that must be managed properly to avoid environmental pollution. The aim of this study was to characterize microorganisms occurring in ship bilge wastes placed in open lagoons and particularly, assess their potential to degrade PAHs. A first-order kinetic was suitable for describing hydrocarbon biodegradation after 17 days of treatment. The calculated rate constants were 0.0668 and 0.0513 d-1 with a corresponding half-life time of 10.3 and 13.5 d for the aliphatic and aromatic hydrocarbon fractions, respectively. At day 17, PAHs removal percentages were: acenaphtylene 100, fluorene 95.2, phenanthrene 93.6, anthracene 70.3, and pyrene 71.5. Methyl phenanthrene removals were lower than that of their parent compound (3-methyl phenanthrene 83.6, 2-methyl phenanthrene 80.8, 1-methyl phenanthrene 77.3, 9-methyl phenanthrene 75.1, and 2,7-dimethyl phenanthrene 76.6). Neither pure cultures nor microbial community from these wastes showed extracellular biosurfactant production suggesting that the addition of an exogenously produced biosurfactant may be important in enhancing hydrocarbon bioavailability and biodegradation. DNA analysis of bilge waste samples revealed an ubiquitous distribution of the nahAc genotype in the dump pools. Although almost all of the isolates grew on naphthalene as sole carbon source, only some of them yielded nahAc amplification under the experimental conditions used. The variety of PAHs in bilge wastes could support bacteria with multiple degradation pathways and a diversity of catabolic genes divergent from the classical nah-like type. New studies considering this approach are currently in progress.