title: Bioremediation potential of a tropical soil contaminated with a mixture of crude oil and production water.
abstract: A typical tropical soil from the northeast of Brazil, where an important terrestrial oil field is located, was accidentally contaminated with a mixture of oil and saline production water. To study the bioremediation potential in this area, molecular methods based on PCR-DGGE were used to determine the diversity of the bacterial communities in bulk and in contaminated soils. Bacterial fingerprints revealed that the bacterial communities were affected by the presence of the mixture of oil and production water, and different profiles were observed when the contaminated soils were compared with the control. Halotolerant strains capable of degrading crude oil were also isolated from enrichment cultures obtained from the contaminated soil samples. Twenty-two strains showing these features were characterized genetically by amplified ribosomal DNA restriction analysis (ARDRA) and phenotypically by their colonial morphology and tolerance to high NaCl concentrations. Fifteen ARDRA groups were formed. Selected strains were analyzed by 16S rDNA sequencing, and Actinobacteria was identified as the main group found. Strains were also tested for their growth capability in the presence of different oil derivatives (hexane, dodecane, hexadecane, diesel, gasoline, toluene, naphthalene, o-xylene, and p-xylene) and different degradation profiles were observed. PCR products were obtained from 12 of the 15 ARDRA representatives when they were screened for the presence of the alkane hydroxylase gene (alkB). Members of the genera Rhodococcus and Gordonia were identified as predominant in the soil studied. These genera are usually implicated in oil degradation processes and, as such, the potential for bioremediation in this area can be considered as feasible.
authors.affiliation: Laboratorio de Genetica Microbiana, Instituto de Microbiologia Prof. Paulo de Goes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Vanessa Marques
authors.initials: VM
authors.lastname: Alvarez
authors.forename: Silvia Cristina Cunha Dos Santos
authors.initials: SC
authors.lastname: Santos
authors.forename: Renata da Costa
authors.initials: Rda C
authors.lastname: Casella
authors.forename: Ronalt Leite
authors.initials: RL
authors.lastname: Vital
authors.forename: Gina Vasquez
authors.initials: GV
authors.lastname: Sebastin
authors.forename: Lucy
authors.initials: L
authors.lastname: Seldin
mesh_terms: D039903:Actinobacteria / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001938:Brazil; D016000:Cluster Analysis; D042926:Cytochrome P-450 CYP4A / Q000235:genetics / Q000378:metabolism; D016172:DNA Fingerprinting; D004586:Electrophoresis; D005798:Genes, Bacterial; D033601:Gordonia Bacterium / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D010578:Petroleum / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D055049:Salt Tolerance; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D042926:Cytochrome P-450 CYP4A