Fomina Marina, Bowen Andrew D, Charnock John M, Podgorsky Valentin S, Gadd Geoffrey M
Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
Institute of Microbiology and Virology, NASU, Zabolotnogo st. 154, Kiev, 03680, Ukraine.
Environ Microbiol. 2017 Mar;19(3):1310-1321. doi: 10.1111/1462-2920.13664. Epub 2017 Feb 1.
This work elucidates spatio-temporal aspects of the biogeochemical transformation of copper mobilized from malachite (Cu (CO )(OH) ) and bioaccumulated within Aspergillus niger colonies when grown on different inorganic nitrogen sources. It was shown that the use of either ammonium or nitrate determined how copper was distributed within the colony and its microenvironment and the copper oxidation state and succession of copper coordinating ligands within the biomass. Nitrate-grown colonies yielded ∼1.7× more biomass, bioaccumulated ∼7× less copper, excreted ∼1.9× more oxalate and produced ∼1.75× less water-soluble copper in the medium in contrast to ammonium-grown colonies. Microfocus X-ray absorption spectroscopy revealed that as the mycelium matured, bioaccumulated copper was transformed from less stable and more toxic Cu(I) into less toxic Cu(II) which was coordinated predominantly by phosphate/malate ligands. With time, a shift to oxalate coordination of bioaccumulated copper occurred in the central older region of ammonium-grown colonies.
本研究阐明了孔雀石（Cu(CO)₂(OH)₂）中释放出的铜在不同无机氮源上生长时，在黑曲霉菌落内生物累积的生物地球化学转化的时空特征。结果表明，使用铵盐或硝酸盐决定了铜在菌落及其微环境中的分布方式，以及生物量中铜的氧化态和铜配位配体的演替。与以铵盐为氮源生长的菌落相比，以硝酸盐为氮源生长的菌落生物量高出约1.7倍，生物累积的铜量少约7倍，草酸盐排泄量多约1.9倍，培养基中水溶性铜的生成量少约1.75倍。微聚焦X射线吸收光谱显示，随着菌丝体成熟，生物累积的铜从不稳定且毒性更强的Cu(I)转化为毒性较弱的Cu(II)，其主要由磷酸盐/苹果酸盐配体配位。随着时间的推移，在以铵盐为氮源生长的菌落中心较老区域，生物累积的铜发生了向草酸盐配位的转变。
