Cobalt(II) sequestration on fungal biogenic manganese oxide enhanced by manganese(II) oxidase activity

Chang, Jianing; Tani, Yukinori; Naitou, Hirotaka; Miyata, Naoyuki; Seyama, Haruhiko; Tanaka, Kohei

doi:10.1016/j.apgeochem.2013.07.023

Cited by 22 publications

(9 citation statements)

References 32 publications

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“…Recent research with strain KR21-2 has demonstrated that newly formed Mn oxides possess Mn(II) oxidase activity, which strongly affects the sorption and redox reactions of metals on the solid Mn phase. The enzyme activity enhances the sorption of metal cations [26][27][28] and oxidation of arsenic(III) [29,30], Co(II) [31], and chromium (III) [32] by the Mn oxides. These observations suggest the crucial role of Mn(II)-oxidizing enzymes associated with solid Mn phase in the fate of diverse elements.…”

Section: Introductionmentioning

confidence: 99%

Molecular Cloning and Heterologous Expression of Manganese(II)-Oxidizing Enzyme from Acremonium strictum Strain KR21-2

et al. 2020

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Diverse ascomycete fungi oxidize manganese(II) [Mn(II)] and produce Mn(III, IV) oxides in terrestrial and freshwater environments. Although multicopper oxidase (MCO) is considered to be a key catalyst in mediating Mn(II) oxidation in ascomycetes, the responsible gene and its product have not been identified. In this study, a gene, named mco1, encoding Mn(II)-oxidizing MCO from Acremonium strictum strain KR21-2 was cloned and heterologously expressed in the methylotrophic yeast Pichia pastoris. Based on the phylogenetic relationship, similarity of putative copper-binding motifs, and homology modeling, the gene product Mco1 was assigned to a bilirubin oxidase. Mature Mco1 was predicted to be composed of 565 amino acids with a molecular mass of 64.0 kDa. The recombinant enzyme oxidized Mn(II) to yield spherical Mn oxides, several micrometers in diameter. Zinc(II) ions added to the reaction mixture were incorporated by the Mn oxides at a Zn/Mn molar ratio of 0.36. The results suggested that Mco1 facilitates the growth of the micrometer-sized Mn oxides and affects metal sequestration through Mn(II) oxidation. This is the first report on heterologous expression and identification of the Mn(II) oxidase enzyme in Mn(II)-oxidizing ascomycetes. The cell-free, homogenous catalytic system with recombinant Mco1 could be useful for understanding Mn biomineralization by ascomycetes and the sequestration of metal ions in the environment

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Section: Introductionmentioning

confidence: 99%

Molecular Cloning and Heterologous Expression of Manganese(II)-Oxidizing Enzyme from Acremonium strictum Strain KR21-2

et al. 2020

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“…The reversible production of Cr VI diss with respect to enzymatic Mn(II) oxidation activity may deny the hypothesis that Cr(OH) 3 precipitation is responsible for anaerobic cessation of Cr(III) oxidation by BMOs. Our previous studies demonstrated the anaerobic cessation of oxidative reactions of As(III) to As(V) [29] and Co(II) to Co(III) [30] by newly formed BMOs, whereas aerobic conditions prevented the cessation of As(III)and Co(II)-oxidation reactions. We assumed the anaerobic cessation of Cr(III) oxidation was due to the surface passivation by the accumulation of reduced Mn(II)/Mn(III) species at the redox reactive sites on BMOs, resulting in insufficient electron transfer from the BMO phase to the reductant species including Cr(III).…”

Section: Cessation Of Cr(iii) Oxidation By Bmos Under Anaerobic Condimentioning

confidence: 92%

“…Thus, the enzymatically active BMOs act as a catalytic agent for Cr(III) oxidation with the terminal electron acceptor of dissolved O 2 , by which homogeneous oxidation of Cr(III) does not proceed under the same conditions ( Figure S2A). Our previous results have demonstrated such catalytic oxidation processes of As(III) to As(V) [29] and of Co(II) to Co(III) [30] (as the terminal electron acceptor of dissolved O 2 ) using newly formed BMOs, which continuously mediates the oxidation reactions without release of reduced Mn. Enzymatically active BMOs also performed, through catalytic mediation, effective Ce(III) to Ce(IV) oxidation with a lower release of Mn(II), where the Ce oxidized/Mn released molar of >200 [54].…”

Section: Cr(iii) Oxidation Efficiency Of Newly Formed Bmos With An Enmentioning

confidence: 98%

“…Acremonium strictum KR21-2, which is capable of enzymatically oxidizing Mn(II) to BMO [51,52], was grown in HAY liquid medium (20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid (HEPES) buffer (pH 7.0) with 1 mM MnSO 4 ) as reported previously [27,30,39,41].…”

Section: Formation Of Fungal Bmos By a Strictum Kr21-2mentioning

confidence: 99%

“…After incubating A. strictum KR21-2 in 1 mM Mn 2+ -supplemented HAY medium (pH 7.0) for harvested, washed with 100 mM 2-morpholinoethanesulfonic acid (MES) buffer (pH 6.0) three times, and treated with 0.1-0.5 mM Cr(NO 3 ) 3 in 100 mM MES (pH 6.0) for 24 h. To monitor the abilities of Cr(III) oxidation and sequestration of newly formed BMO under air-equilibrated (aerobic) and N 2 gas-purged (anaerobic) conditions as reported previously [30,39,41]. Supernatants were sampled at 0, 2, 4, 8, and 24 h, separated by centrifugation (11,000× g for 2 min), and preserved in 2% HNO 3 .…”

Section: Cr(iii)-oxidizing Ability Of Newly Formed and Heated Bmos Atmentioning

confidence: 99%

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Sequestration and Oxidation of Cr(III) by Fungal Mn Oxides with Mn(II) Oxidizing Activity

et al. 2019

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Biogenic manganese oxides (BMOs) have gained increasing attention for environmental application because of their sequestration and oxidizing abilities for various elements. Oxidation and sequestration of Cr(III) by BMOs, however, still remain unknown. We prepared BMOs in liquid cultures of Acremonium strictum strain KR21-2, and subsequently conducted single or repeated treatment experiments in Cr(NO3)3 at pH 6.0. Under aerobic conditions, newly formed BMOs exhibited a rapid production of Cr(VI) without a significant release of Mn(II), demonstrating that newly formed BMO mediates a catalytic oxidation of Cr(III) with a self-regeneration step of reduced Mn. In anaerobic solution, newly formed BMOs showed a cessation of Cr(III) oxidation in the early stage of the reaction, and subsequently had a much smaller Cr(VI) production with significant release of reduced Mn(II). Extraordinary sequestration of Cr(III) was observed during the repeated treatments under anaerobic conditions. Anaerobically sequestered Cr(III) was readily converted to Cr(VI) when the conditions became aerobic, which suggests that the surface passivation is responsible for the anaerobic cessation of Cr(III) oxidation. The results presented herein increase our understanding of the roles of BMO in Cr(III) oxidation and sequestration processes in potential application of BMOs towards the remediation of Cr(III)/Cr(VI) in contaminated sites.

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Sequestration of Cd(II) and Ni(II) ions on fungal manganese oxides associated with Mn(II) oxidase activity

Chang¹,

Tani²,

Naitou³

et al. 2014

Applied Geochemistry

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Cobalt(II) sequestration on fungal biogenic manganese oxide enhanced by manganese(II) oxidase activity

Cited by 22 publications

References 32 publications

Molecular Cloning and Heterologous Expression of Manganese(II)-Oxidizing Enzyme from Acremonium strictum Strain KR21-2

Molecular Cloning and Heterologous Expression of Manganese(II)-Oxidizing Enzyme from Acremonium strictum Strain KR21-2

Sequestration and Oxidation of Cr(III) by Fungal Mn Oxides with Mn(II) Oxidizing Activity

Sequestration of Cd(II) and Ni(II) ions on fungal manganese oxides associated with Mn(II) oxidase activity

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