Dynamics of a marine-microbial community during biodegradation of bilge waste hydrocarbons

MARINA NIEVAS; MARCELA FERRERO; NELDA LILA OLIVERA; HEBE DIONISI; MARTA COMMENDATORE; JOSÉ LUIS ESTEVES; VERÓNICA BUCALÁ

Puerto Madryn, Chubut, Argentina.

Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The aim of this study was to identify the dominant taxons of a hydrocarbon-degrading microbial community enriched from bilge waste oily phase, and to assess its population dynamics during bilge waste biodegradation. Samples were retrieved from an aerated batch bioreactor with 2.1 g/L total hydrocarbons in seawater medium during a 14-day biodegradation experiment. Total DNA was analyzed by PCR-DGGE, and the relative intensity of each dominant band calculated. Members of the genus Marinobacter were dominant in the enrichment, and Pseudomonas, Shewanella and Halomonas were also detected. During the biodegradation experiment, the exponential-growth phase agreed with n-alkane depletion and an increase in the prevalence of Pseudomonas and Shewanella. Only after emulsification, biodegradation of other more recalcitrant hydrocarbons found in an unresolved complex mixture (UCM) occurred, associated with a predominance of Marinobacter and Shewanella. Cluster analysis from DGGE fingerprints showed shifts in the microbial community structure which matches with the pattern of sequential hydrocarbon biodegradation found (n-alkanes-UCM). Shewanella, a genus which can use diverse electron acceptors such as metals and colonizes emulsified oil from spills, showed high prevalence during both n-alkane and UCM biodegradation of bilge wastes, suggesting a promising potential for bioremediation.