A novel sulfatase for acesulfame degradation in wastewater treatment plants as evidenced fromShinellastrains

Abstract

The artificial sweetener acesulfame is a persistent pollutant in wastewater worldwide. So far, only a few bacterial isolates were recently found to degrade acesulfame efficiently. InBoseaandChelatococcusstrains, a Mn2+-dependent metallo-β-lactamase-type sulfatase and an amidase signature family enzyme catalyze acesulfame hydrolysis via acetoacetamide-N-sulfonate (ANSA) to acetoacetate. Here, we describe a new acesulfame sulfatase inShinellastrains isolated from German wastewater treatment plants. Their genomes do not encode the Mn2+-dependent sulfatase. Instead, a formylglycine-dependent sulfatase gene was found, together with the ANSA amidase gene on a plasmid shared by all known acesulfame-degradingShinellastrains. Heterologous expression, shotgun proteomics and size exclusion chromatography corroborated the physiological function of theShinellaenzyme as a Mn2+-independent acesulfame sulfatase. Since both theBosea/Chelatococcussulfatase and the novelShinellasulfatase are absent in other bacterial genomes or metagenome assembled genomes, we surveyed 60 tera base pairs of wastewater-associated metagenome raw datasets. TheBosea/Chelatococcussulfatase gene was regularly found from 2014 on, particularly in North America, Europe and East Asia, whereas theShinellasulfatase gene was first detected in 2020. The completeShinellapathway is only present in five datasets from China, Finland and Mexico, suggesting that it emerged quite recently in wastewater treatment facilities.