Isolation and Characterization of Novel Bacteria Capable of Degrading 1,4-Dioxane in the Presence of Diverse Co-Occurring Compounds

Abstract

Biodegradation is found to be a promising, cost-effective and eco-friendly option for the treatment of industrial wastewater contaminated by 1,4-dioxane (1,4-D), a highly stable synthetic chemical and probable human carcinogen. This study aimed to isolate, identify, and characterize metabolic 1,4-D-degrading bacteria from a stable 1,4-D-degrading microbial consortium. Three bacterial strains (designated as strains TS28, TS32, and TS43) capable of degrading 1,4-D as a sole carbon and energy source were isolated and identified as Gram-positive Pseudonocardia sp. (TS28) and Gram-negative Dokdonella sp. (TS32) and Afipia sp. (TS43). This study, for the first time, confirmed that the genus Dokdonella is involved in the biodegradation of 1,4-D. The results reveal that all of the isolated strains possess inducible 1,4-D-degrading enzymes and also confirm the presence of a gene encoding tetrahydrofuran/dioxane monooxygenase (thmA/dxmA) belonging to group 5 soluble di-iron monooxygenases (SDIMOs) in both genomic and plasmid DNA of each of the strains, which is possibly responsible for the initial oxidation of 1,4-D. Moreover, the isolated strains showed a broad substrate range and are capable of degrading 1,4-D in the presence of additional substrates, including easy-to-degrade compounds, 1,4-D biodegradation intermediates, structural analogs, and co-contaminants of 1,4-D. This indicates the potential of the isolated strains, especially strain TS32, in removing 1,4-D from contaminated industrial wastewater containing additional organic load. Additionally, the results will help to improve our understanding of how multiple 1,4-D-degraders stably co-exist and interact in the consortium, relying on a single carbon source (1,4-D) in order to develop an efficient biological 1,4-D treatment system.

Isolation and characterization of pure cultures for metabolizing 1,4-dioxane in oligotrophic environments

“…1,4-Dioxane biodegradation is initiated by enzymes encoding soluble di-iron monooxygenase (SDIMO) genes. SDIMO genes also have the ability to catalyze the initial oxidation of a wide variety of hydrocarbons ( Li et al 2014 ; Inoue et al 2016 ; Tusher et al 2021 ). To date, three SDIMO gene clusters (Group-2, Group-5, and Group-6) have been confirmed to be involved in the metabolic biodegradation of 1,4-dioxane ( Table S1 ).…”

“… Li et al (2014) found a positive correlation between the biodegradation of 1,4-dioxane and the abundance of Group-5 SDIMO genes, tetrahydrofuran/dioxane monooxygenase ( thmA/dxmA ). Genes thmA/dxmA also were identified in the 1,4-dioxane-metabolizing bacteria that belong to the genera Dokdonella, Afipia , and Pseudonocardia ( Inoue et al 2016 ; Tusher et al 2021 ) ( Table 2 ). Similarly, tetrahydrofuran monooxygenase gene cluster ( thmADBC ) was expressed by Pseudonocardia dioxanivorans CB1190 during growth on 1,4-dioxane ( Grostern et al 2012 ; Sales et al 2013 ).…”

“…About 20 bacterial strains ( Supporting Information Table S1 ) have been reported in the literature to use 1,4-dioxane as the sole carbon and energy source ( Parales et al 1994 ; Mahendra & Alvarez-Cohen 2005 , 2006 ; Kim et al 2009 ; Sei et al 2013a ; Huang et al 2014 ; Pugazhendi et al 2015 ; Chen et al 2016 ; Inoue et al 2016 ; Matsui et al 2016 ; He et al 2017b ; Barajas-Rodriguez & Freedman 2018 ; Inoue et al 2018 ; Yamamoto et al 2018 ; Tusher et al 2020 ; Ma et al 2021 ; Simmer et al 2021 ; Tusher et al 2021 ; Dai et al 2022 ; Ramos-García et al 2022 ). The majority of them are gram-positive bacteria that belong to the genera Pseudonocardia, Mycobacterium , and Rhodococcus .…”

Efficacy of Continuous Flow Reactors for Biological Treatment of 1,4-Dioxane Contaminated Textile Wastewater Using a Mixed Culture

“…[51], Mycobacterium sp. PH-06 [39] Afipia [52,53], Dokdonella [53], Xanthobacter [26,54] and Flavobacterium [3]. However, in this study, a mixed culture was tested with two types of bioreactors, CSTR and PFR, on the lab scale.…”

Multi-Technique Investigation of Grave Robes from 17th and 18th Century Crypts Using Combined Spectroscopic, Spectrometric Techniques, and New-Generation Sequencing

“…[41]. Moreover, Dokdonella sp is reported as a microorganism able to degrade ethers [42]. Enzymes produced by these bacteria could be involved in the degradation of dyes and may be responsible for the weak retention of colours.…”