Naphthenic acid biodegradation by the unicellular alga Dunaliella tertiolecta
| Autor: | Lisa M. Gieg, Dean M. Quesnel, Iyswarya Mani Bhaskar, Gordon Chua |
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| Rok vydání: | 2010 |
| Předmět: |
Environmental Engineering
Cyclohexanecarboxylic Acids Health Toxicology and Mutagenesis Carboxylic acid Carboxylic Acids Chlorophyceae Chlorophyta Acetates chemistry.chemical_compound Algae Cyclohexanes Naphthenic acid Environmental Chemistry chemistry.chemical_classification biology Waste management Public Health Environmental and Occupational Health General Medicine General Chemistry Cyclohexanecarboxylic acid Biodegradation biology.organism_classification Pollution Tailings Butyrates Biodegradation Environmental chemistry Environmental chemistry Volvocida Water Pollutants Chemical |
| Zdroj: | Chemosphere. 84(4) |
| ISSN: | 1879-1298 |
| Popis: | Naphthenic acids (NAs) are a major contributor to toxicity in tailings waste generated from bitumen production in the Athabasca Oil Sands region. While investigations have shown that bacteria can biodegrade NAs and reduce tailings toxicity, the potential of algae to biodegrade NAs and the biochemical mechanisms involved remain poorly understood. Here, we discovered that the marine alga Dunaliella tertiolecta is able to tolerate five model NAs (cyclohexanecarboxylic acid, cyclohexaneacetic acid, cyclohexanepropionic acid, cyclohexanebutyric acid and 1,2,3,4-tetrahydro-2-naphthoic acid) at 300 mg L −1 , a level which exceeds that of any single or combination of NAs typically found in tailings ponds. Moreover, we show that D. tertiolecta can metabolize four of the model NAs. Analysis of NA-amended cultures of D. tertiolecta via low resolution gas chromatography–mass spectrometry allowed us to quantify decreasing NA levels, identify metabolites, and formulate putative mechanisms of biodegradation. Degradation of cyclohexanebutyric acid and cyclohexanepropionic acid proceeded via β-oxidation and resulted in the transient accumulation of cyclohexaneacetic acid and cyclohexanecarboxylic acid, respectively. Cyclohexanecarboxylic acid was metabolized via 1-cyclohexenecarboxylic acid suggesting that further degradation may occur by step-wise β-oxidation. When D. tertiolecta was inoculated in the presence of oil sands tailings water from the Athabasca region, biodegradation of single-ring NAs was observed relative to controls. This result corroborates the trend we observed with the single-ring model NAs. |
| Databáze: | OpenAIRE |
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