Mechanism and application of bacterial exopolysaccharides: An advanced approach for sustainable heavy metal abolition from soil

• Published in: Carbohydrate research 2024-10, Vol.544, p.109247, Article 109247
• Main Authors: Ghosh, Ankita, Sah, Diksha, Chakraborty, Moumita, Rai, J.P.N.
• Format: Article
• Language: English
• Subjects: Bacteria - metabolism; Bacterial exopolysaccharides; Biodegradation, Environmental; Bioremediation; Eco-friendly alternatives; Environmental sustainability; Heavy metal contamination; Metals, Heavy - chemistry; Metals, Heavy - metabolism; Microbial biosorbents; Polysaccharides, Bacterial - chemistry; Soil - chemistry; Soil Microbiology; Soil Pollutants - chemistry; Soil Pollutants - metabolism; Soil remediation
• ISSN: 0008-6215; 1873-426X; 1873-426X
• DOI: 10.1016/j.carres.2024.109247

The escalation of heavy metal pollutants in soils and effluents, driven by industrialization and human activities, poses significant environmental and health risks. Conventional remediation methods are often costly and ineffective, prompting a shift towards sustainable alternatives such as biological treatments. Natural biosorbents, including microbial cells and their byproducts, have emerged as promising solutions. One such approach involves leveraging exopolysaccharides (EPS), complex high-molecular-weight biopolymers synthesized by microbes under environmental stress conditions. EPS are intricate organic macromolecules comprising proteins, polysaccharides, uronic acids, humic compounds, and lipids, either located within microbial cells or secreted into their surroundings. Their anionic functional groups enable efficient electrostatic binding of cationic heavy metals, making EPS effective biosorbents for soil remediation. This review thoroughly explores the pivotal role of bacterial EPS in the removal of heavy metals, focusing on EPS biosynthesis mechanisms, the dynamics of interaction with heavy metals, and case studies that illustrate their effectiveness in practical remediation strategies. By highlighting these aspects, the review underscores the innovation and practical implications of EPS-based bioremediation technologies, demonstrating their potential to address critical environmental challenges effectively while paving the way for sustainable environmental management practices. Key findings reveal that EPS exhibit robust metal-binding capacities, facilitated by their anionic functional groups, thereby offering a promising solution for mitigating metal pollution in diverse environmental matrices. [Display omitted] •EPS from microbial synthesis effectively bind heavy metals in soil remediation.•Anionic functional groups enhance EPS' electrostatic interactions with heavy metals.•EPS show up to 90 % metal-binding efficiency in contaminated soils.•Microbial EPS biosynthesis increases under heavy metal stress by 40–60 %.•EPS-based bioremediation provides cost-effective and sustainable alternatives.