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Aerobic degradation of ethyl‐ tert ‐butyl ether by a microbial consortium: Selection and evaluation of biodegradation ability
Author(s) -
Kharoune Mourad,
Kharoune Lynda,
Lebault JeanMichael,
Pauss André
Publication year - 2002
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620211007
Subject(s) - biodegradation , degradation (telecommunications) , microbial consortium , ether , environmental chemistry , chemistry , selection (genetic algorithm) , environmental science , organic chemistry , biology , engineering , bacteria , microorganism , computer science , telecommunications , genetics , artificial intelligence
A microbial consortium that degrades ethyl‐ tert ‐butyl ether (ETBE) as the sole source of carbon and energy under aerobic conditions was selected from a gasoline‐polluted soil. This consortium consists of a variety of microorganisms with a predominance of filamentous morphology. Degradation of ETBE was found to be solely related to bacterial activity. After prolonged cultivation followed by successive transfers, the consortium's degradation ability was improved and reached a specific degradation rate of 95 mg/g protein /h (about 146 mg/g dry wt /h). This exceeds the previously reported rates in the literature for ETBE‐degrading microorganisms as pure or mixed cultures. Furthermore, a stoichiometric balance of chemical oxygen demand (COD) removal and oxygen uptake with ETBE removal provides indirect evidence of complete degradation. The consortium's activity was not inhibited by high ETBE concentrations (≤1,600 mg/L), and large inoculum sizes (≥120 mg protein /L) were desirable for a faster and complete degradation of ETBE. The enriched consortium was also able to completely degrade methyl‐ tert ‐butyl ether (MTBE), tert ‐amyl methyl ether (TAME), and tert ‐butyl alcohol (TBA), both alone and in mixture with ETBE, without any measurable release of major degradation intermediates. In each case, MTBE and TAME exhibited the most significant resistance to degradation while TBA was rapidly degraded.