Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion

IntroductionHeavy metal pollution adversely affects soil health by disrupting the microbial community structure and functions. The current study aimed to isolate and characterize heavy metal-tolerant bacterial strains and evaluate their potential for soil bioremediation and promoting agricultural su...

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Main Authors: Saira Abbas, Sobia Zulfiqar, Muhammad Arshad, Nauman Khalid, Amjad Hussain, Iftikhar Ahmed
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-08-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1644466/full
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author Saira Abbas
Saira Abbas
Sobia Zulfiqar
Muhammad Arshad
Nauman Khalid
Nauman Khalid
Amjad Hussain
Amjad Hussain
Iftikhar Ahmed
author_facet Saira Abbas
Saira Abbas
Sobia Zulfiqar
Muhammad Arshad
Nauman Khalid
Nauman Khalid
Amjad Hussain
Amjad Hussain
Iftikhar Ahmed
author_sort Saira Abbas
collection DOAJ
description IntroductionHeavy metal pollution adversely affects soil health by disrupting the microbial community structure and functions. The current study aimed to isolate and characterize heavy metal-tolerant bacterial strains and evaluate their potential for soil bioremediation and promoting agricultural sustainability.MethodsA total of 68 bacterial strains were isolated from industrial discharge-contaminated sites and screened for their maximum tolerance limits (MTL) against Cr, Cu, Pb, As, and Cd. The biosorption potential of 23 phylogenetically diverse strains was evaluated. Molecular identification was carried out through 16S rRNA gene sequencing, and plant growth-promoting genes (acdS and nifH) were screened. Four representative strains (NCCP-650T, NCCP-614, NCCP-644, and NCCP-602) were tested for their effect on the growth of Brassica napus under axenic conditions with 50 mg/L of each metal.ResultsSeveral isolates exhibited high MTLs, with tolerance up to 3600 mg/L for Cr, 3300 mg/L for Cu, and 3000 mg/L for Cd and As, while Pb tolerance reached 2100 mg/L. Biosorption was highest for Pb, followed by Cd and Cu; Cr and As were less effectively biosorbed. Molecular identification revealed affiliation of strains to 19 bacterial genera, with Bacillus (21%), Pseudomonas (12%), and Staphylococcus (10%) as dominant. Seven strains harbored both acdS and nifH genes, with 15 and 8 strains positive for nifH and acdS individually. In plant experiments, all four tested strains improved B. napus growth under heavy metal stress, with NCCP-650T showing the most significant enhancement.DiscussionThe isolated strains demonstrated significant tolerance and biosorption of toxic metals, along with plant growth-promoting potential. These findings suggest that selected isolates, particularly NCCP-650T, can serve as bioinoculants for enhancing plant growth and bioremediation in metal-contaminated environments.
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spelling doaj-art-dd18c9de26ec419db0bac5b4ccb5f91f2025-08-20T03:41:05ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-08-011610.3389/fmicb.2025.16444661644466Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotionSaira Abbas0Saira Abbas1Sobia Zulfiqar2Muhammad Arshad3Nauman Khalid4Nauman Khalid5Amjad Hussain6Amjad Hussain7Iftikhar Ahmed8National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, PakistanDepartment of Zoology, University of Science and Technology, Bannu, PakistanNational Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, PakistanInstitute of Environmental Sciences and Engineering, School of Civil and Environmental Engineering, National University of Sciences and Technology (NUST), Islamabad, PakistanSchool of Food and Agriculture, University of Management and Technology, Lahore, PakistanCollege of Health Sciences, Abu Dhabi University, Abu Dhabi, United Arab EmiratesCollege of Health Sciences, Abu Dhabi University, Abu Dhabi, United Arab EmiratesHigher Education Commission, Islamabad, PakistanNational Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, PakistanIntroductionHeavy metal pollution adversely affects soil health by disrupting the microbial community structure and functions. The current study aimed to isolate and characterize heavy metal-tolerant bacterial strains and evaluate their potential for soil bioremediation and promoting agricultural sustainability.MethodsA total of 68 bacterial strains were isolated from industrial discharge-contaminated sites and screened for their maximum tolerance limits (MTL) against Cr, Cu, Pb, As, and Cd. The biosorption potential of 23 phylogenetically diverse strains was evaluated. Molecular identification was carried out through 16S rRNA gene sequencing, and plant growth-promoting genes (acdS and nifH) were screened. Four representative strains (NCCP-650T, NCCP-614, NCCP-644, and NCCP-602) were tested for their effect on the growth of Brassica napus under axenic conditions with 50 mg/L of each metal.ResultsSeveral isolates exhibited high MTLs, with tolerance up to 3600 mg/L for Cr, 3300 mg/L for Cu, and 3000 mg/L for Cd and As, while Pb tolerance reached 2100 mg/L. Biosorption was highest for Pb, followed by Cd and Cu; Cr and As were less effectively biosorbed. Molecular identification revealed affiliation of strains to 19 bacterial genera, with Bacillus (21%), Pseudomonas (12%), and Staphylococcus (10%) as dominant. Seven strains harbored both acdS and nifH genes, with 15 and 8 strains positive for nifH and acdS individually. In plant experiments, all four tested strains improved B. napus growth under heavy metal stress, with NCCP-650T showing the most significant enhancement.DiscussionThe isolated strains demonstrated significant tolerance and biosorption of toxic metals, along with plant growth-promoting potential. These findings suggest that selected isolates, particularly NCCP-650T, can serve as bioinoculants for enhancing plant growth and bioremediation in metal-contaminated environments.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1644466/fullheavy metalsPGPRtannery dischargebiosorptionbioremediation
spellingShingle Saira Abbas
Saira Abbas
Sobia Zulfiqar
Muhammad Arshad
Nauman Khalid
Nauman Khalid
Amjad Hussain
Amjad Hussain
Iftikhar Ahmed
Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
Frontiers in Microbiology
heavy metals
PGPR
tannery discharge
biosorption
bioremediation
title Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
title_full Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
title_fullStr Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
title_full_unstemmed Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
title_short Molecular characterization of heavy metal-tolerant bacteria and their potential for bioremediation and plant growth promotion
title_sort molecular characterization of heavy metal tolerant bacteria and their potential for bioremediation and plant growth promotion
topic heavy metals
PGPR
tannery discharge
biosorption
bioremediation
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1644466/full
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