TY - JOUR

T1 - Antimony Isotope Fractionation during Kinetic Sb(III) Oxidation by Antimony-Oxidizing Bacteria Pseudomonas sp. J1

AU - Jia, Xiaocen

AU - Kaufmann, Andreas

AU - Lazarov, Marina

AU - Wen, Bing

AU - Weyer, Stefan

AU - Zhou, Jianwei

AU - Ma, Liyuan

AU - Majzlan, Juraj

N1 - Publisher Copyright: © 2024 American Chemical Society.

PY - 2024/7/2

Y1 - 2024/7/2

N2 - Antimony (Sb) isotopic fractionation is frequently used as a proxy for biogeochemical processes in nature. However, to date, little is known about Sb isotope fractionation in biologically driven reactions. In this study, Pseudomonas sp. J1 was selected for Sb isotope fractionation experiments with varying initial Sb concentration gradients (50-200 μM) at pH 7.2 and 30 °C. Compared to the initial Sb(III) reservoir (δ123Sb = 0.03 ± 0.01 ∼ 0.06 ± 0.01‰), lighter isotopes were preferentially oxidized to Sb(V). Relatively constant isotope enrichment factors (ϵ) of −0.62 ± 0.06 and −0.58 ± 0.02‰ were observed for the initial Sb concentrations ranging between 50 and 200 μM during the first 22 days. Therefore, the Sb concentration has a limited influence on Sb isotope fractionation during Sb(III) oxidation that can be described by a kinetically dominated Rayleigh fractionation model. Due to the decrease in the Sb-oxidation rate by Pseudomonas sp. J1, observed for the initial Sb concentration of 200 μM, Sb isotope fractionation shifted toward isotopic equilibrium after 22 days, with slightly heavy Sb(V) after 68 days. These findings provide the prospect of using Sb isotopes as an environmental tracer in the Sb biogeochemical cycle.

AB - Antimony (Sb) isotopic fractionation is frequently used as a proxy for biogeochemical processes in nature. However, to date, little is known about Sb isotope fractionation in biologically driven reactions. In this study, Pseudomonas sp. J1 was selected for Sb isotope fractionation experiments with varying initial Sb concentration gradients (50-200 μM) at pH 7.2 and 30 °C. Compared to the initial Sb(III) reservoir (δ123Sb = 0.03 ± 0.01 ∼ 0.06 ± 0.01‰), lighter isotopes were preferentially oxidized to Sb(V). Relatively constant isotope enrichment factors (ϵ) of −0.62 ± 0.06 and −0.58 ± 0.02‰ were observed for the initial Sb concentrations ranging between 50 and 200 μM during the first 22 days. Therefore, the Sb concentration has a limited influence on Sb isotope fractionation during Sb(III) oxidation that can be described by a kinetically dominated Rayleigh fractionation model. Due to the decrease in the Sb-oxidation rate by Pseudomonas sp. J1, observed for the initial Sb concentration of 200 μM, Sb isotope fractionation shifted toward isotopic equilibrium after 22 days, with slightly heavy Sb(V) after 68 days. These findings provide the prospect of using Sb isotopes as an environmental tracer in the Sb biogeochemical cycle.

KW - antimony (Sb)

KW - isotope fractionation

KW - kinetic-dominated

KW - microbial oxidation

KW - Sb(III)-oxidizing bacteria

UR - http://www.scopus.com/inward/record.url?scp=85197094690&partnerID=8YFLogxK

U2 - 10.1021/acs.est.3c10271

DO - 10.1021/acs.est.3c10271

M3 - Article

C2 - 38887934

AN - SCOPUS:85197094690

VL - 58

SP - 11411

EP - 11420

JO - Environmental Science and Technology

JF - Environmental Science and Technology

SN - 0013-936X

IS - 26

ER -