PRISMA-based review of Pseudomonas spp. in microbial heavy-metal bioremediation: mechanisms and taxonomy

TL;DR

This review compares Pseudomonas and Bacillus bacteria in cleaning up heavy metals, highlighting Pseudomonas' versatility and the need for better research standards.

Contribution

The paper provides a PRISMA-based analysis of recent studies on Pseudomonas spp. and their bioremediation mechanisms.

Findings

Bacillus spp. achieved the highest removal efficiencies (80%-90%) through biosorption and biomineralization.

Pseudomonas spp. showed high versatility with mechanisms like efflux systems and enzymatic transformations.

Median removal efficiencies were 70% in lab settings but only 10%-25% in soil, indicating performance gaps.

Abstract

Bioremediation may be sustainable strategy for mitigating heavy-metal contamination in soils and related environmental matrices.

This paper, based on PRISMA 2020 guidelines analyzes 41 experimental studies published between 2022 and 2025, selected from Scopus, Web of Science, and PubMed, with the aim of comparing bacterial taxa, detoxification mechanisms, and remediation performance.

Bacillus and Pseudomonas were the most frequently investigated genera, with Bacillus spp. achieving the highest removal efficiencies (>80%–90%) through biosorption and biomineralization mechanisms. On the other hand, Pseudomonas spp. showed a high functional and genetic versatility, combining efflux systems, enzymatic redox transformations, EPS production, and biofilm-mediated resilience, particularly in multi-metal and fluctuating environmental conditions. Median removal efficiencies was at least 70% in controlled laboratory assays, while it was 10%–25% in soil. Despite methodological heterogeneity, the evidence identifies Pseudomonas as a mechanistic benchmark genus rather than a universally superior biosorbent, owing to its extensive genomic characterization and broad detoxification repertoire. The review highlights the need for standardized experimental protocols, integration of multi-omics approaches, and field-scale validation to improve data comparability and to facilitate the translation of microbial bioremediation from laboratory studies to sustainable environmental applications.

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