Sphingomonas turrisvirgatae a new agar-degrading Sphingomonas species

Sphingomonas turrisvirgatae (type strain MCT13T), was isolated from a drainage ditch within a disused system of constructed wetlands, flowing through uncultivated land. Its growth on agarized media is associated with clearing and pitting around the colonies, a feature so far never reported among sphingomonads. The MCT13T isolate is characterized by a quite narrow carbon sources assimilation spectrum, and agarase activity is enhanced on poor media. This trait suggests the existence of nutrients-related regulation mechanisms, and/or the possibility of associative interactions with other environmental microorganisms. The analysis of the S. turrisvirgatae (MCT13T) draft genome, has detected the presence of four different agarase-like enzymes encoding genes. Up to now, agarolytic activity has been more often found in marine-bacteria and has not been observed in any of the characterized or validly published Sphingomonas species. A BLAST search, using the amino acid sequences of the four putative agarases, showed the best alignment scores (48 to 71% identity) with three proteins of the uncharacterized Caulobacter sp. X isolate, where the genes order is also partially conserved. The preliminary bioinformatics analyses have also detected the presence of genes potentially useful in bioremediation or in industrial applications, rendering Sphingomonas turrisvirgatae MCT13T, a possible tool for both the degradation of complex carbohydrates and pollutants.