Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-08T14:52:24.919Z Has data issue: false hasContentIssue false

Psychrotolerant hydrocarbon-degrading Rhodococcus strains isolated from polluted Antarctic soils

Published online by Cambridge University Press:  28 February 2005

LUCAS A.M. RUBERTO
Affiliation:
Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 6º piso (C1113AAD), Buenos Aires, Argentina
S. VAZQUEZ
Affiliation:
Consejo Nacional de Investigaciones Científicas y Técnicas, Rivadavia 1917 (C1033AAJ), Buenos Aires, Argentina
A. LOBALBO
Affiliation:
Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 6º piso (C1113AAD), Buenos Aires, Argentina
W.P. MAC CORMACK
Affiliation:
Instituto Antártico Argentino, Departamento de Biología, Cerrito 1248 (C1010AAZ), Buenos Aires, Argentina

Abstract

Three hydrocarbon-degrading Rhodococcus strains isolated from polluted Antarctic soils proved to be closely related despite their different origins. Strains had a similar hydrocarbon degradation pattern and optimum growth temperature ranged between 25ºC and 30ºC, showing that strains are psychrotolerant but not psychrophiles. Specific growth rate on rich media ranged between 0.12 and 0.21 h−1, higher than those observed on hydrocarbons as carbon source. Results suggest that in Antarctic contaminated soils, closely related Rhodococcus strains are present and could play an important role in decontamination. Microcosm systems showed that, although the natural microflora respond significantly to the pollutants, bioaugmentation with Rhodococcus strain (ADH), improved biodegradation either alone or mixed with a hydrocarbon-degrading Acinetobacter strain. In comparison with microcosm where only ADH was inoculated, a non-significant decrease in hydrocarbon concentration was observed when ADH was inoculated as mixed culture with a previously tested strain. Pollutants dramatically reduced bacterial groups in soils resulting in a dominance of Pseudomonas. Microcosms showed that when natural microflora has no previous history of exposure to the pollutants, bioaugmentation with autochthonous strains improves degradation of the contaminants. The positive response of the native bacteria to the pollutants leaves the question open as to whether bioaugmentation is necessary when soils have a long previous exposure to hydrocarbons.

Type
Research Article
Copyright
© Antarctic Science Ltd 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)