1,4-Dioxane degradation characteristics of Rhodococcus aetherivorans JCM 14343

Abstract

Rhodococcus aetherivorans JCM 14343 can degrade 1,4-dioxane as a sole carbon and energy source. This study aimed to characterize this 1,4-dioxane degradation ability further, and assess the potential use of the strain for 1,4-dioxane removal in industrial wastewater. Strain JCM 14343 was able to degrade 1,4-dioxane inducibly, and its 1,4-dioxane degradation was also induced by tetrahydrofuran and 1,4-butanediol. The demonstration that 1,4-butanediol not only induced but also enhanced 1,4-dioxane degradation was a novel finding of this study. Although strain JCM 14343 appeared not to be an effective 1,4-dioxane degrader considering the maximum specific 1,4-dioxane degradation rate (0.0073 mg-dioxane/mg-protein/h), half saturation concentration (59.2 mg/L), and cell yield (0.031 mg-protein/mg-1,4-dioxane), the strain could degrade over 1100 mg/L of 1,4-dioxane and maintain its degradation activity at a wide range of temperature (5-40 °C) and pH (4-9) conditions. This suggests the usefulness of strain JCM 14343 in 1,4-dioxane treatment under acidic and cold conditions. In addition, 1,4-dioxane degradation experiments in the presence of ethylene glycol (EG) or other cyclic ethers revealed that 1,4-dioxane degradation by strain JCM 14343 was inhibited in the presence of other cyclic ethers, but not by EG, suggesting certain applicability of strain JCM 14343 for industrial wastewater treatment.

Field Test of On-Site Treatment of 1,4-Dioxane-Contaminated Groundwater Using <i>Pseudonocardia</i> sp. D17

“…A reason for this phenomenon was the repression of physiological activities, including 1,4-dioxane-degradation activity, of strain D17 by environmental and operational factors such as the limitation of readily-utilizable organic compounds (Table 1) and other trace elements in groundwater and/or the endogenous respiration caused by excess aeration. Previous studies have reported the possibility of the repression of 1,4-dioxane biodegradation by catabolite repression and/or metabolic flux dilution [20,39]. Given the low 1,4-dioxane concentration in the presence of other utilizable organic compounds (i.e., BOD) in the contaminated groundwater, the 1,4-dioxane degradation ability of strain D17 might be repressed by catabolite repression and/or metabolic flux dilution.…”

Enrichment and Analysis of Stable 1,4-dioxane-Degrading Microbial Consortia Consisting of Novel Dioxane-Degraders

“…However, the growth and degradation rates of most of the previously reported dioxane-degraders are found to be low [8]. In addition, several studies found that 1,4-dioxane biodegradation using pure strains can be inhibited in the presence of co-contaminants like heavy metals, chlorinated and fluorinated compounds, or additional carbon sources like aromatic hydrocarbons [11,[24][25][26], by affecting the microbes, their metabolic activity, and the responsible enzymes [3,27,28]. On the other hand, metabolic degradation is considered to be relatively advantageous over the co-metabolic degradation, since the latter process requires additional substrates to supply auxiliary electron donors for inducing dioxane-degrading enzymes in microbial populations [29].…”

“…It is also used as a surfactant in foods, detergents, and cosmetics, and particularly as a stabilizing agent for chlorinated solvents, especially 1,1,1-trichloroethane (1,1,1-TCA), trichloroethene (TCE), and tetrachloroethene (PCE) [8,10]. Moreover, it is formed as an undesirable by-product during the manufacture of ethylene oxide, ethylene glycol, polyesters, and surfactants, including polysorbates, sorbitol, and sorbitan [8,9,11]. Due to the extensive use and unintentional formation of 1,4-dioxane during industrial processes, this xenobiotic compound is often found in domestic sewage and industrial wastewater at a concentration of several hundred mg/L [12,13].…”

Draft Genome Sequence of Rhodococcus aetherivorans JCM 14343 T , a Bacterium Capable of Degrading Recalcitrant Noncyclic and Cyclic Ethers

“…M embers of the genus Rhodococcus possess the versatile ability to catabolize a variety of xenobiotic organic pollutants and are useful for the bioremediation of polluted environments (1,2). Among the members of this genus, Rhodococcus aetherivorans is a species of special interest in the biodegradation of various recalcitrant organic pollutants, such as noncyclic and cyclic ethers (3)(4)(5), petroleum compounds (6), and chlorinated organic compounds (7). The type strain of this species, R. aetherivorans JCM 14343 (originally named strain 10bc312), was originally isolated from petrochemical biotreater sludge as a methyl tert-butyl ether (MTBE)-degrading strain (3).…”

“…The type strain of this species, R. aetherivorans JCM 14343 (originally named strain 10bc312), was originally isolated from petrochemical biotreater sludge as a methyl tert-butyl ether (MTBE)-degrading strain (3). Our recent study revealed that this strain is also capable of degrading recalcitrant cyclic ethers, such as 1,4-dioxane and tetrahydrofuran (4). To further understand the genetic basis of the degradation of ethers and other abilities, genome sequence analysis of R. aetherivorans JCM 14343 T was performed.…”