Diatoms in Bioremediation: Quantitative Insights, Mechanistic Advances, and Future Smart Bioengineering Perspectives

Abstract

Global water pollution has exceeded the critical levels due to unchecked industrialization, agricultural runoff, and domestic waste discharge. The decade has witnessed shifting attention towards microalgae-based systems in the search for sustainable, energy-efficient, and circular remediation technologies. Diatoms (Bacillariophyceae), stand out among them for their unique nanostructured silica frustules, robust photosynthetic efficiency, and adaptability to extreme environmental gradients. This review extensively examines the potential of diatoms in bioremediation across diverse pollutant classes: nutrients, heavy metals, hydrocarbons, dyes, microplastics and pharmaceuticals by integrating quantitative data from recent studies (2015–2025). Species-specific pollutant removal efficiencies are analyzed, with instances like Nitzschia palea achieving an impressive 95% phenanthrene removal (10 mg L⁻¹) and Navicula pelliculosa eliminating 87% phosphate from municipal wastewater. We have also reviewed mechanistic insights into biosorption, bioaccumulation, enzymatic biotransformation, and diatom bacteria symbiosis in the context of modern nanobiotechnology. The paper further explores emerging frontiers such as diatom-inspired nanomaterials, AI-assisted monitoring, and omics-guided strain optimization. Integrating these capabilities with circular bioeconomy principles could ascertain diatoms as the cornerstone of smart phycoremediation systems capable of mitigating pollution while generating biofuels, nutraceuticals, and biosilica products.