Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings

To promote environmentally sustainable remediation and resource recovery from ion-adsorption rare earth tailings (IRET), this study comprehensively investigated the previously isolated strain REO-01 by examining its sulfate-reducing performance, Cd(II) immobilization potential, and physiological and...

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Main Authors: Ping Zhang, Chaoyang Wei, Fen Yang
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/7/1511
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author Ping Zhang
Chaoyang Wei
Fen Yang
author_facet Ping Zhang
Chaoyang Wei
Fen Yang
author_sort Ping Zhang
collection DOAJ
description To promote environmentally sustainable remediation and resource recovery from ion-adsorption rare earth tailings (IRET), this study comprehensively investigated the previously isolated strain REO-01 by examining its sulfate-reducing performance, Cd(II) immobilization potential, and physiological and biochemical responses under varying environmental conditions. Strain REO-01 was identified as a Gram-negative facultative anaerobe with strong sulfate-reducing activity and effective Cd(II) immobilization capacity. During a 96 h incubation period, the strain entered the exponential growth phase within 36 h, after which the OD<sub>600</sub> values plateaued. Concurrently, the culture pH increased from 6.83 to 7.5, and the oxidation-reduction potential (ORP) declined to approximately −300 mV. Cd(II) concentrations decreased from 0.2 mM to 3.33 μM, corresponding to a removal efficiency exceeding 95%, while sulfate concentrations declined from 1500 mg/L to 640 mg/L, with a maximum reduction efficiency of 66.16%. The strain showed optimal growth at 25–40 °C and near-neutral pH (6–7), whereas elevated Cd(II) concentrations (≥0.2 mM) significantly inhibited cell growth. A sulfate concentration of 1500 mg/L was found to be optimal for cellular activity. Among the tested carbon sources, sodium lactate at 4.67 g/L yielded the most favorable results, reducing ORP to −325 mV, increasing pH to 7.6, and lowering Cd(II) and sulfate concentrations to 3.33 μM and 510 mg/L, respectively. These findings highlight the strong potential of strain REO-01 for simultaneous sulfate reduction and Cd(II) remediation, supporting its application in the in situ bioremediation and resource utilization of rare earth tailings.
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spelling doaj-art-8741be5c8a244812a110f79adab70ed72025-08-20T02:47:10ZengMDPI AGMicroorganisms2076-26072025-06-01137151110.3390/microorganisms13071511Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth TailingsPing Zhang0Chaoyang Wei1Fen Yang2School of Environmental Science And Engineering, Tongji University, Siping Rd. 1239, Shanghai 200092, ChinaKey Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaKey Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaTo promote environmentally sustainable remediation and resource recovery from ion-adsorption rare earth tailings (IRET), this study comprehensively investigated the previously isolated strain REO-01 by examining its sulfate-reducing performance, Cd(II) immobilization potential, and physiological and biochemical responses under varying environmental conditions. Strain REO-01 was identified as a Gram-negative facultative anaerobe with strong sulfate-reducing activity and effective Cd(II) immobilization capacity. During a 96 h incubation period, the strain entered the exponential growth phase within 36 h, after which the OD<sub>600</sub> values plateaued. Concurrently, the culture pH increased from 6.83 to 7.5, and the oxidation-reduction potential (ORP) declined to approximately −300 mV. Cd(II) concentrations decreased from 0.2 mM to 3.33 μM, corresponding to a removal efficiency exceeding 95%, while sulfate concentrations declined from 1500 mg/L to 640 mg/L, with a maximum reduction efficiency of 66.16%. The strain showed optimal growth at 25–40 °C and near-neutral pH (6–7), whereas elevated Cd(II) concentrations (≥0.2 mM) significantly inhibited cell growth. A sulfate concentration of 1500 mg/L was found to be optimal for cellular activity. Among the tested carbon sources, sodium lactate at 4.67 g/L yielded the most favorable results, reducing ORP to −325 mV, increasing pH to 7.6, and lowering Cd(II) and sulfate concentrations to 3.33 μM and 510 mg/L, respectively. These findings highlight the strong potential of strain REO-01 for simultaneous sulfate reduction and Cd(II) remediation, supporting its application in the in situ bioremediation and resource utilization of rare earth tailings.https://www.mdpi.com/2076-2607/13/7/1511ion-adsorption rare earth tailingssulfate-reducing bacteriametabolic activity of SRBcadmium immobilizationcarbon source optimization
spellingShingle Ping Zhang
Chaoyang Wei
Fen Yang
Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
Microorganisms
ion-adsorption rare earth tailings
sulfate-reducing bacteria
metabolic activity of SRB
cadmium immobilization
carbon source optimization
title Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
title_full Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
title_fullStr Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
title_full_unstemmed Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
title_short Optimization of Growth Conditions of <i>Desulfovibrio desulfuricans</i> Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings
title_sort optimization of growth conditions of i desulfovibrio desulfuricans i strain reo 01 and evaluation of its cd ii bioremediation potential for detoxification of rare earth tailings
topic ion-adsorption rare earth tailings
sulfate-reducing bacteria
metabolic activity of SRB
cadmium immobilization
carbon source optimization
url https://www.mdpi.com/2076-2607/13/7/1511
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AT chaoyangwei optimizationofgrowthconditionsofidesulfovibriodesulfuricansistrainreo01andevaluationofitscdiibioremediationpotentialfordetoxificationofrareearthtailings
AT fenyang optimizationofgrowthconditionsofidesulfovibriodesulfuricansistrainreo01andevaluationofitscdiibioremediationpotentialfordetoxificationofrareearthtailings