Endophytic bacteria stimulate mercury phytoremediation by modulating its bioaccumulation and volatilization

The quantification, efficiency, and possible mechanisms of mercury phytoremediation by endophytic bacteria are poorly understood. Here we selected 8 out of 34 previously isolated endophytic bacterial strains with a broad resistance profile to metals and 11 antibiotics: Acinetobacter baumannii BacI43...

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Bibliographic Details
Published in:Ecotoxicology and environmental safety 2020-10, Vol.202, p.110818-110818, Article 110818
Main Authors: Mello, Ivani Souza, Targanski, Sabrina, Pietro-Souza, William, Frutuoso Stachack, Fernando Ferrari, Terezo, Ailton Jose, Soares, Marcos Antônio
Format: Article
Language:English
Subjects:
Antibiotics
Bioaccumulation
Bioremediation
Metal
Volatilization
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Summary:The quantification, efficiency, and possible mechanisms of mercury phytoremediation by endophytic bacteria are poorly understood. Here we selected 8 out of 34 previously isolated endophytic bacterial strains with a broad resistance profile to metals and 11 antibiotics: Acinetobacter baumannii BacI43, Bacillus sp. BacI34, Enterobacter sp. BacI14, Klebsiella pneumoniae BacI20, Pantoea sp. BacI23, Pseudomonas sp. BacI7, Pseudomonas sp. BacI38, and Serratia marcescens BacI56. Except for Klebsiella pneumoniae BacI20, the other seven bacterial strains promoted maize growth on a mercury-contaminated substrate. Acinetobacter baumannii BacI43 and Bacillus sp. BacI34 increased total dry biomass by approximately 47%. The bacteria assisted mercury remediation by decreasing the metal amount in the substrate, possibly by promoting its volatilization. The plants inoculated with Serratia marcescens BacI56 and Pseudomonas sp. BacI38 increased mercury volatilization to 47.16% and 62.42%, respectively. Except for Bacillus sp. BacI34 and Pantoea sp. BacI23, the other six bacterial strains favored mercury bioaccumulation in plant tissues. Endophytic bacteria-assisted phytoremediation contributed to reduce the substrate toxicity assessed in different model organisms. The endophytic bacterial strains selected herein are potential candidates for assisted phytoremediation that shall help reduce environmental toxicity of mercury-contaminated soils. •Resistance to mercury and multimetals correlates positively in endophytic bacteria.•Resistance to mercury and antibiotics correlates positively in endophytic bacteria.•Multimetal-resistant bacteria increase maize growth in mercury-contaminated soil.•Endophytic bacteria inoculation promotes mercury bioaccumulation and volatilization.•Soil remediation by inoculated plants reduces environmental toxicity levels.
ISSN:0147-6513
1090-2414
DOI:10.1016/j.ecoenv.2020.110818