Quantifying Microbially Mediated Kinetics of Ferrihydrite Transformation and Arsenic Reduction: Role of the Arsenate-Reducing Gene Expression Pattern

• DOI: 10.1021/acs.est.9b07137
• Publication Date: 2020-04-30T18:56:12Z
• Authors: Zhenqing Shi; Shiwen Hu; Jingyi Lin; Tongxu Liu; Xiaomin Li; Fangbai Li
• Keywords: Ferrihydrite; Shewanella putrefaciens; Genetic algorithm; Biogeochemical Cycle

The behavior of arsenic (As) is usually coupled with iron (Fe) oxide transformation and mediated by both abiotic reactions microbial processes in the environment. However, quantitative models for kinetic processes, which specifically consider arsenate-reducing gene expression correspondent to different reaction conditions, are lacking. In this study, based on pure cultured Shewanella putrefaciens incubation experiments, extended X-ray absorption fine structure spectroscopy, high resolution transmission electron microscopy, a suite analyses, we developed kinetics model microbially As reduction Fe quantified As(V) rate coefficients patterns arrA genes. reasonably described temporal changes speciation distribution. rates varied dramatically during reactions, were well represented varying transcript abundances genes at concentrations. contributions biotic overall assessed. results improved our understanding key role As(V)-reducing regulating distribution As. modeling approaches promising developing comprehensive biogeochemical involving multiple reactions.