Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples
- PDF / 91,442 Bytes
- 7 Pages / 595 x 785 pts Page_size
- 88 Downloads / 163 Views
O R I G I N A L PA P E R
Artur Eduardo Ribeiro Bastos · David Henry Moon · Antonio Rossi · Jack Thomas Trevors · Siu Mui Tsai
Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples
Received: 15 March 2000 / Revised: 9 August 2000 / Accepted: 4 September 2000 / Published online: 12 October 2000 © Springer-Verlag 2000
Abstract Two phenol-degrading microorganisms were isolated from Amazonian rain forest soil samples after enrichment in the presence of phenol and a high salt concentration. The yeast Candida tropicalis and the bacterium Alcaligenes faecalis were identified using several techniques, including staining, morphological observation and biochemical tests, fatty acid profiles and 16S/18S rRNA sequencing. Both isolates, A. faecalis and C. tropicalis, were used in phenol degradation assays, with Rhodococcus erythropolis as a reference phenol-degrading bacterium, and compared to microbial populations from wastewater samples collected from phenol-contaminated environments. C. tropicalis tolerated higher concentrations of phenol and salt (16 mM and 15%, respectively) than A. faecalis (12 mM and 5.6%). The yeast also tolerated a wider pH range (3–9) during phenol degradation than A. faecalis (pH 7–9). Phenol degradation was repressed in C. tropicalis by acetate and glucose, but not by lactate. Glucose and acetate had little effect, while lactate stimulated phenol degradation in A. faecalis. To our knowledge, these soils had never been contaminated with man-made phenolic compounds and this is the first report of phenol-degrading microorganisms from Amazonian forest soil samples. The results support the idea that natural uncontaminated environments contain sufficient genetic diversity to make them valid choices for the isolation of microorganisms useful in bioremediation.
A. E. R. Bastos · A. Rossi Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, USP, CEP 14.040–901, Ribeirão Preto, SP, Brazil D. H. Moon · S. M. Tsai Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenário 303, Caixa Postal 96, CEP 13.400–970, Piracicaba, SP, Brasil J. T. Trevors (✉) Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada, N1G2W1 e-mail: [email protected], Fax: +1-519-837-0442
Keywords Alcaligenes faecalis · Candida tropicalis · Biodegradation · Phenol · Salinity
Introduction Although contamination of soils and waters with chemically synthesized phenolic compounds is a serious environmental problem, their remediation may be possible using physical, chemical and biological methods, such as bioremediation (Leung et al. 1997; Errampalli et al. 1997). Bioremediation represents an environmentally less aggressive procedure and there is increasing interest in identifying metabolic capabilities within natural microbial populations. Phenol and its derivatives are aerobically biodegraded by two main metabolic pathways, initiated either by ortho or meta cleavage (Leonard and Lindley 1998; Muller and Babel 1994). The
Data Loading...
