Aerobic degradation of ethyl‐tert‐butyl ether by a microbial consortium: Selection and evaluation of biodegradation ability

Abstract

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 (< or = 1,600 mg/L), and large inoculum sizes (> or = 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.

Ethyl tert-butyl ether (EtBE) degradation by an algal-bacterial culture obtained from contaminated groundwater

“…After 24 h, 13 C TBA concentrations increased relatively compared with declining 13 C EtBE concentrations, indicating that TBA is indeed a metabolite from EtBE degradation. This is in line with previous reports suggesting that TBA is the main metabolite of EtBE degradation (Kharoune et al, 2002;Ohkubo and Yagi, 2012). Although 13 CO 2 was detected by NMR, we were not sure if complete EtBE degradation up to CO 2 was occurring.…”

“…Error bars represent standard deviations based on analytical replicates of the same fed-batch reactor sample. Kharoune et al, 2002;Le Digabel et al, 2013;Ohkubo and Yagi, 2012). The higher aerobic EtBE degradation rates determined in previous studies might be due to the fact that those cultures were either pure cultures or enrichments obtained with EtBE at relatively high oxygen concentrations.…”

Degradation of fuel components

“…After 24 h, 13 C TBA concentrations increased relatively compared with declining 13 C EtBE concentrations, indicating that TBA is indeed a metabolite from EtBE degradation. This is in line with previous reports suggesting that TBA is the main metabolite of EtBE degradation [209,210]. Although 13 gene copies/ml sample in the fed-batch reactor, however, their role in the EtBE degradation is not known.…”

Sorption characteristics of ethyl tert-butyl ether to Chinese reference soils

“…Some works have been done on ETBE environmental issues in the past decades, such as water quality and ETBE use (Zogorski et al 1996), ETBE biodegradation (Hernandez-Perez et al 2001;Kharoune et al 2002;Steffan et al 1997), ETBE toxicity to animals and humans (McGregor 2007;Stanard et al 2003), transfer in water-air systems of ETBE (Arp and Schmidt 2004), and effect of ETBE solubility by temperature (Gonzalez-Olmos and Iglesias 2008).…”