Systematic review synthesizes microbial responses to anthropogenic pollutants

Anthropogenic activity, driven by industrialization, agricultural practices, and waste disposal, has emerged as a predominant contributing factor to environmental pollution. These activities release substantial amounts of toxic pollutants into the environment, such as heavy metals, organic pollutants, microplastics, and nanomaterials, adversely affecting various ecosystems. These toxic substances can exert considerable stress on various microorganisms, including bacteria, fungi, and microalgae. The impact of anthropogenic pollutants on microorganisms is a nascent area of study, particularly as environmental stressors continue to increase in both quantity and complexity. This review aims to enhance our understanding of how microorganisms (bacteria, microalgae, and fungi) respond to the anthropogenic pollutants including heavy metals, organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), nanomaterials and microplastics. It explores the toxic effects of these pollutants on diverse microbial species. Furthermore, the review covers studies that examine the molecular mechanisms underlying microbial resistance both through natural resistance processes and adaptive laboratory evolution or evolutionary engineering strategies. The review also highlights how omics technologies such as genomics, transcriptomics, proteomics and metabolomics reveal conserved and unique molecular mechanisms to gain insight into the pollutant-specific and organism-specific adaptation strategies. Nevertheless, limitations in community-level multi-omics studies, the relatively limited data on fungi, and the challenges associated with studying mixed cultures hinder a comprehensive understanding of microbial response and resistance mechanisms to anthropogenic pollutants. Addressing these gaps will be pivotal in leveraging the molecular mechanisms to guide the development of novel strategies to obtain pollutant-tolerant strains for bioremediation, bio-monitoring, and synthetic biology applications.