Enbaia, S, Eswayah, A, Hondow, N orcid.org/0000-0001-9368-2538 et al. (2 more authors) (2020) Detoxification, active uptake, and intracellular accumulation of chromium species by a methane-oxidizing bacterium. Applied and Environmental Microbiology. ISSN 0099-2240
Abstract
Despite the wide-ranging proscription of hexavalent chromium, chromium (VI) remains among the major polluting heavy metals worldwide. Aerobic methane-oxidizing bacteria are widespread environmental microorganisms that can perform diverse reactions using methane as the feedstock. The methanotroph Methylococcus capsulatus Bath, like many other microorganisms, detoxifies chromium (VI) by reduction to chromium (III). Here, the interaction of chromium species with M. capsulatus Bath was examined in detail by using a range of techniques. Cell fractionation and HPLC-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) indicated that externally provided chromium (VI) underwent reduction, and was then taken up into the cytoplasmic and membranous fractions of the cells. This was confirmed by X-ray photoelectron spectroscopy (XPS) of intact cultures that indicated negligible chromium on the surface of, or outside, the cells. Distribution of chromium and other elements within intact and sectioned cells, as observed via transmission electron microscope (TEM) combined with energy-dispersive X-ray spectroscopy (EDX), and electron energy loss spectroscopy (EELS), was consistent with the cytoplasm/membrane location of the chromium (III), possibly as chromium phosphate. The cells could also take up chromium (III) directly from the medium in a metabolically dependent fashion, and accumulate it within the cells. These results indicate a novel pattern of interaction with chromium species distinct from that observed previously with other microorganisms. They also suggest that M. capsulatus, and similar methanotrophs may contribute directly to chromium (VI) reduction, and accumulation in mixed communities of microorganisms that are able to perform methane-driven remediation of chromium (VI).
Metadata
Item Type: | Article |
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Authors/Creators: |
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Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 Dec 2020 15:00 |
Last Modified: | 14 Dec 2020 15:00 |
Status: | Published online |
Publisher: | American Society for Microbiology |
Identification Number: | 10.1128/aem.00947-20 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:168972 |