Analyzing microbial communities and metabolic functions in estuaries affected by human activity to uncover bioelectrochemical system potential

In the context of bioelectrochemical systems (BES), a profound understanding of the taxonomic composition within indigenous microbial communities is crucial. Their metabolic versatility assumes a foundational role in dictating the functionality of BES, yielding diverse applications for bioenergy production and bioremediation in anthropogenically impacted estuaries. Employing high-throughput sequencing of the V3-V4 region of 16S rRNA and predictive metagenomic analyses of three different estuaries samples (eutrophicated urban reservoir, mud volcano impacted river, and its river mouth), this study delves into the intricate interplay between these communities and their metabolic functions in response to human-induced perturbations, with a specific focus on their applicability to BES. Our findings illuminate remarkable distinctions among the three samples, manifesting in variations in microbial composition and functional metabolic pathways within the respective ecosystems. The mud volcano-affected river, characterized by the highest microbial diversity, exhibited the most diverse array of functional metabolic processes, prominently dominated by chemoheterotrophy (67.43%). In contrast, the river mouth displayed a distinct penchant for autotrophy (33.33%). The eutrophicated urban reservoir showcased a balanced coexistence of chemoheterotrophy (41.18%) and autotrophy (35.29%). Regarding metabolic potential for BES application, most of metabolism potential were associated with anodic activity, while cathodic activity was restricted to autotrophy and its relatives. The results suggested that the microbial communities anthropogenically impacted estuaries were potentially used for anodic and cathodic reactions in BES as electrogens to generate bioelectricity and reduce of pollutants.