Mangrove fungi in action: Novel bioremediation strategy for high-chloride wastewater

Abstract

Bioremediation of extremely high-chloride wastewater poses significant challenges due to the adverse effects of elevated salt concentrations on most microorganisms, where chloride levels can be as high as 7% (w/v). Mangrove wetlands derived fungus, Aspergillus aculeatus, emerged as a promising candidate, capable of removing approximately 40% of chloride ions in environments with concentration of 15% (w/v), representative of industrial wastewater conditions. Transcriptomics and biochemical assays conducted under increasing salt conditions revealed that elevated chloride concentrations induce the expression and activity of S-adenosyl methionine-dependent methyltransferase, which facilitates the conversion of chloride into chloromethane. This is the first report characterizing the biological mechanism behind high salt tolerance and chloride removal capacity of Aspergillus aculeatus. This salt remediation mechanism may work as a starter for developing future bioremediation strategies to treat high-chloride wastewater using fungi, offering an eco-friendly alternative to traditional physical or chemical methods.