Nucleating biofilms for biotechnology using synthetic polymers

Abstract

<p>This project is on developing robust biocatalysts in the form of enzymes expressed in biofilms. The aim is to design polymer scaffolds onto which bacteria adhere in a controlled manner, to form biofilms that can be used in biotechnology. Poly(acryloyl hydrazide) has been chosen as the polymer scaffold, due to easy synthesis and post-polymerization modification resulting in highly functional polymers<sup>1</sup> that are predicted to interact and cluster bacteria together. In this study poly(acryloyl hydrazide) with a range of hydrophobic functionalities were used to cluster and interact with two biofilm forming isogenic E.coli K-12 strains; PHL644 containing a point mutation ompR234 resulting in the overexpression of curli (a biofilm adhesin) and its parental wild type MC4100, with data showing correlations between polymer hydrophobicity, bacterial clustering and biofilm intensity in both strains. </p> <p>Data suggests these polymer induced clusters go on to develop many of the traits of a biofilm; crystal violet staining, lectin staining, and the use of reporter genes have confirmed the presence of extracellular polymeric substances, with their expression levels being directly linked to polymer hydrophobicity. Furthermore our polymers are able to boost biofilm intensity of MC4100 to the levels of PHL644, thereby opening up a potential avenue for non-biofilm forming but industrially relevant strains to experience the benefits of being in biofilm form (robustness, chemical and mechanical resistance).</p> <p>Biocatalytic ability of our polymer induced biofilms has also been tested, again with polymer properties dictating biotransformation yields.</p> <p>Finally, preliminary results have shown that we are able to selectively disperse our polymer induced biofilms, and then re-induce them by simply altering polymer properties in situ, providing a potentially useful reversible platform.</p> <ol> <li><strong>Polym. Chem.</strong>, 2017,<strong>8</strong>, 4576-4584</li> </ol>