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Physiological and molecular characterization of a microbial community established in unsaturated, petroleum‐contaminated soil
Author(s) -
Kasai Yuki,
Takahata Yoh,
Hoaki Toshihiro,
Watanabe Kazuya
Publication year - 2005
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2005.00754.x
Subject(s) - temperature gradient gel electrophoresis , biology , environmental chemistry , soil microbiology , soil contamination , microbial population biology , bioremediation , gammaproteobacteria , 16s ribosomal rna , contamination , soil water , bacteria , chemistry , ecology , genetics
Summary The microbial communities established in soil samples from an unsaturated, petroleum‐contaminated zone and from an adjacent uncontaminated site were characterized by physiological and molecular approaches. Possible electron acceptors such as sulfate and nitrate had been completely depleted in these soil samples. Slurries of these soil samples were incubated in bottles in the presence of hydrocarbon indicators (benzene, toluene, xylene and decane), and the degradation of these compounds was examined. Supplementation with electron acceptors stimulated hydrocarbon degradation, although the stimulatory effect was small in the contaminated soil. The initial degradation rates in the contaminated soil under fermentative/methanogenic conditions were comparable to those under aerobic conditions. The microbial populations in the original soil samples were analysed by cloning and sequencing of polymerase chain reaction (PCR)‐amplified bacterial and archaeal 16S rRNA gene fragments, showing that the sequences retrieved from these soils were substantially different. For instance, Epsilonproteobacteria , Gammaproteobacteria , Crenarchaeota and Methanosarcinales could only be detected at significant levels in the contaminated soil. Denaturing gradient gel electrophoresis (DGGE) analyses of 16S rRNA gene fragments amplified by PCR from the incubated soil‐slurry samples showed that supplementation of the electron acceptors resulted in a shift in the major populations, while the DGGE profiles after incubating the contaminated soil under the fermentative/methanogenic conditions were not substantially changed. These results suggest that petroleum contamination of the unsaturated zone resulted in the establishment of a fermentative/methanogenic community with substantial hydrocarbon‐degrading potential.