Stimulatory and inhibitory effects of metals on 1, 4-dioxane degradation by four different 1, 4-dioxane-degrading bacteria. (January 2020)

• Record Type: Journal Article
• Authors: Inoue, Daisuke; Tsunoda, Tsubasa; Sawada, Kazuko; Yamamoto, Norifumi; Sei, Kazunari; Ike, Michihiko
• Is Part Of: Chemosphere. Volume 238(2020)
• Publication Date: 2020-01
• Subjects: 1, 4-Dioxane biodegradation -- Inhibition -- Stimulation -- Soluble di-iron monooxygenase -- Transition metal; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.124606
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: This study evaluates the effects of various metals on 1, 4-dioxane degradation by the following four bacteria: Pseudonocardia sp. D17; Pseudonocardia sp. N23; Mycobacterium sp. D6; and Rhodococcus aetherivorans JCM 14343. Eight transition metals [Co(II), Cu(II), Fe(II), Fe(III), Mn(II), Mo(VI), Ni(II), and Zn(II)] were used as the test metals. Results revealed, for the first time, that metals had not only inhibitory but also stimulatory effects on 1, 4-dioxane biodegradation. Cu(II) had the most severe inhibitory effects on 1, 4-dioxane degradation by all of the test strains, with significant inhibition at concentrations as low as 0.01–0.1 mg/L. This inhibition was probably caused by cellular toxicity at higher concentrations, and by inhibition of degradative enzymes at lower concentrations. In contrast, Fe(III) enhanced 1, 4-dioxane degradation by Mycobacterium sp. D6 and R. aetherivorans JCM 14343 the most, while degradation by the two Pseudonocardia strains was stimulated most notably in the presence of Mn(II), even at concentrations as low as 0.001 mg/L. Enhanced degradation is likely caused by the stimulation of soluble di-iron monooxygenases (SDIMOs) involved in the initial oxidation of 1, 4-dioxane. Differences in the stimulatory effects of the tested metals were likely associated with the particular SDIMO types in the test strains. Highlights: Effects of 8 metals on 1, 4-dioxane degradation by 4 bacterial strains were studied. Cu(II) commonly had the most severe inhibitory effects on degradation. Cu(II) at low concentrations probably inhibited degradation enzymes. Mn(II) and Fe(III) stimulated degradation depending on the degrading strain. Stimulation by metals was likely associated with SDIMO types in the strains.