A\nNovel Sulfatase for Acesulfame Degradation in Wastewater\nTreatment Plants as Evidenced from <i>Shinella</i> Strains

The artificial sweetener\nacesulfame is a persistent pollutant in\nwastewater worldwide. So far, only a few bacterial isolates were recently\nfound to degrade acesulfame efficiently. In <i>Bosea</i> and <i>Chelatococcus</i> strains, a Mn<sup>2+</sup>-dependent\nmetallo-β-lactamase-type sulfatase and an amidase signature\nfamily enzyme catalyze acesulfame hydrolysis via acetoacetamide-<i>N</i>-sulfonate to acetoacetate. Here, we describe a new acesulfame\nsulfatase in <i>Shinella</i> strains isolated from wastewater\ntreatment plants in Germany. Their genomes do not encode the Mn<sup>2+</sup>-dependent sulfatase. Instead, a formylglycine-dependent\nsulfatase gene was found, together with the acetoacetamide-<i>N</i>-sulfonate amidase gene on a plasmid\nshared by all known acesulfame-degrading <i>Shinella</i> strains. Heterologous expression, proteomics, and size exclusion\nchromatography corroborated the physiological function of the <i>Shinella</i> sulfatase in acesulfame hydrolysis. Since both\nacesulfame sulfatase types are absent in other bacterial genomes or\nmetagenome-assembled genomes, we surveyed 73 tera base pairs of wastewater-associated\nmetagenome raw data sets. <i>Bosea</i>/<i>Chelatococcus</i> sulfatase gene signatures were regularly found from 2013, particularly\nin North America, Europe, and East Asia, whereas <i>Shinella</i> sulfatase gene signatures were first detected in 2020. Moreover,\nsignatures for the <i>Shinella</i> sulfatase and amidase\ngenes co-occur only in six data sets from China, Finland, and Mexico,\nsuggesting that the <i>Shinella</i> genes were enriched\nor introduced quite recently in wastewater treatment facilities.