Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Research on Microbes
Microbiology Experts
Online Submission
Access Statistics

Site Visitors

blog tracking

Applied and Environmental Microbiology
Vol. 72, No: 9 , 2006; Pages: 6316-6324

Microbial Population Dynamics Associated with Crude-Oil Biodegradation in Diverse Soils

Natsuko Hamamura,* Sarah H. Olson, David M. Ward, and William P. Inskeep

Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717


Soil bacterial population dynamics were examined in several crude-oil-contaminated soils to identify those organisms associated with alkane degradation and to assess patterns in microbial response across disparate soils. Seven soil types obtained from six geographically distinct areas of the United States (Arizona, Oregon, Indiana, Virginia, Oklahoma, and Montana) were used in controlled contamination experiments containing 2% (wt/wt) crude oil spiked with [1-14C]hexadecane. Microbial populations present during hydrocarbon degradation were analyzed using both 16S rRNA gene sequence analysis and by traditional methods for cultivating hydrocarbon-oxidizing bacteria. After a 50-day incubation, all seven soils showed comparable hydrocarbon depletion, where >80% of added crude oil was depleted and approximately 40 to 70% of added [14C]hexadecane was converted to 14CO2. However, the initial rates of hydrocarbon depletion differed up to 10-fold, and preferential utilization of shorter-chain-length n-alkanes relative to longer-chain-length n-alkanes was observed in some soils. Distinct microbial populations developed, concomitant with crude-oil depletion. Phylogenetically diverse bacterial populations were selected across different soils, many of which were identical to hydrocarbon-degrading isolates obtained from the same systems (e.g., Nocardioides albus, Collimonas sp., and Rhodococcus coprophilus). In several cases, soil type was shown to be an important determinant, defining specific microorganisms responding to hydrocarbon contamination. However, similar Rhodococcus erythropolis-like populations were observed in four of the seven soils and were the most common hydrocarbon-degrading organisms identified via cultivation.

Keywords: Microbial Population ,Crude-Oil Biodegradation,16S rRNA gene ,14C,Rhodococcus erythropolis.

Corresponding author: Phone: (406) 994-5549. Fax: (406) 994-3933

E-mail: nhamamura{at}montana.edu


Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution