ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiotechnology
This article is part of the Research TopicRecent Advances and Techniques in Bioremediation with ExtremophilesView all articles
Enhanced immobilization of cadmium, lead, and antimony with improved soil fertility using sulfate-reducing bacteria@nano zero-valent iron-modified biochar: Coupled chemisorption and microbial mechanisms
Provisionally accepted
Shirui Peng1Fengshuo Ya1Juan Yin2Changjun Liao2Dangling Qin2Jiapan Lian1
Hong Li3Hailong Wang4
Jianming Xue5Xiaoe Yang6Hongfei Lin2Jiancheng Chen1Guofei Pan1
Yanyan Wei1*- 1Guangxi University, Nanning, China
- 2Nanning Bossco Environmental Protection Technology Co., Ltd, Nanning, China
- 3Chongqing University, Chongqing, China
- 4Foshan University, Foshan, China
- 5New Zealand Forest Research Institute, Christchurch, New Zealand
- 6Zhejiang University, Hangzhou, China
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Soil co-contamination with cadmium (Cd), lead (Pb), and antimony (Sb) poses significant environmental and health risks, highlighting the need for effective remediation strategies. Sulfate-reducing bacteria (SRB) are promising for bioremediation, but require optimization to improve effectiveness. Here, we developed SRB@nZVI@BC, a novel composite integrating SRB, nano zero-valent iron-modified biochar (nZVI@BC), and sodium alginate (SA). Its optimal preparation conditions were identified as 2% SA, 2% CaCl2, 30% SRB solution, and 0.1% nZVI@BC based on mass transfer performance, mechanical strength, and sulfate reduction rate. The application of SRB@nZVI@BC increased the proportion of stable forms of Cd, Pb, and Sb in soil and achieved removal efficiencies of 60.22%–63.93% for Cd, 57.13%–59.45% for Pb, and 56.02%–70.37% for Sb in leachate. Compared to alone SRB treatment, SRB@nZVI@BC significantly enhanced SRB activity, promoting sulfur cycling and the generation of S2⁻, thereby facilitated heavy metal precipitation as insoluble sulfides. SRB@nZVI@BC could improve the adsorption capacity of soil for heavy metals by activating the oxygen-containing functional groups such as C-O-C. Moreover, SRB@nZVI@BC reshaped the soil microbial community by enriching sulfate-reducing genera such as Desulfosporosinus and Desulfitobacterium, driving heavy metal transformation and stabilization. The composite further enhanced soil nutrient availability (N, P, K) and increased enzyme activities, contributing to soil fertility recovery. Overall, SRB@nZVI@BC provides an eco-friendly solution for stabilizing multi-metal-contaminated soils and promoting the restoration of barren lands through synergistic adsorption and biomineralization.
Keywords: immobilized bacteria, heavy metal, biochar, Nanoscale zero valent iron, SRB
Received: 25 Sep 2025; Accepted: 26 Nov 2025.
Copyright: © 2025 Peng, Ya, Yin, Liao, Qin, Lian, Li, Wang, Xue, Yang, Lin, Chen, Pan and Wei. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yanyan Wei
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