Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples

• Published in: Archives of microbiology Vol. 174; no. 5; pp. 346 - 352
• Main Authors: RIBEIRO BASTOS, Artur Eduardo, MOON, David Henry, ROSSI, Antonio, TREVORS, Jack Thomas, SIU MUI TSAI
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-11-2000; Berlin
• Subjects: Agronomy. Soil science and plant productions; Alcaligenes - classification; Alcaligenes - genetics; Alcaligenes - isolation & purification; Alcaligenes - metabolism; Alcaligenes faecalis; Bacterial Typing Techniques; Biochemistry and biology; Biodegradation of pollutants; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; Brazil; Candida - classification; Candida - genetics; Candida - isolation & purification; Candida - metabolism; Candida tropicalis; Chemical, physicochemical, biochemical and biological properties; Culture Media; Environment and pollution; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Microbiology; Mycological Typing Techniques; Phenols - metabolism; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Sodium Chloride - metabolism; Soil Microbiology; Soil science; Trees; Brazil; Enrichment; Halotolerance; Candidiasis; Yeast; Mycosis; Sample; Rain forest; Lipids; Alcaligenes faecalis; Forest soil; Salinity; Fungi; Infection; Salt; Phenol; Rain; Phenols; Bacteria; Candida tropicalis; Isolate; Isolation; Fungi Imperfecti; Microorganism; Thallophyta
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s002030000216

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 faecoalis 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.