Substrate Specificity and Stability of a Novel Alginate Lyase From Stenotrophomonas Maltophilia

Stenotrophomonas maltophilia is a gram-negative bacteria that is an increasing important nocosomial pathogen in immunocompromised patients. Approximately 1% of all nosocomal bacteraemias are due to S. maltophilia infection, with the attributed mortality rate at nearly 28%, placing it among the highest attributed mortality rates observed for nosocomal bacteraemias. A major reason for the high mortality associated with S. maltophilia is its ability to produce exopolysaccharides (EPS) that form a biofilm resistant to antimicrobials, as well as enable binding to stents and ventilators. Our goal is to characterize an alginate lyase (AlgL) discovered in our group for selectivity to degrade the EPS present in S. maltophilia biofilms. I developed a high-yield E. coli expression system for AlgL, characterized the secondary structure as a function of solution conditions and measured the kinetic parameters for EPS degradation as a function of temperature. My results indicate the discovered AlgL is robust to high temperatures, and may be a useful starting point for removing biofilm-resistant infections.