Improved enzymatic hydrolysis of polymers by modulation of adsorption
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Förbättrad wnzymatisk hydrolys av polymerer genom modulering av adsorption (Swedish)
Application areas for synthetic polymers are constantly increasing hence demand of improved polymer properties, where functionalization of polymer surface is one approach. The currently utilized methods have large environmental impacts and decrease the quality of polymers resulting in an interest of alternative methods, like enzymatic treatment. The main limitation with enzymatic treatment is slow processes since synthetic polymers are unnatural substrate for enzymes. Genetic engineering is in general applied to increase enzymatic efficiency by enlarging the are around the active site and/or modify the active site. Upcoming is fusion of binding modules to enzymes to facilitate adsorption on insoluble substrates. In this study, has a hydrophobin (hfb4jecorina) originating from Trichoderma reesei been fused to a cutinase from Thermobifida cellulosilytica DSM444535 (Thc_Cut1+Hyd). Additionally, has the carbohydrate binding module from cellobiohydrolase I from T. reesei and the substrate binding domain origin from Ralstonia ickettii T1 been fused to a codon optimized adsorption behavior on insoluble synthetic polymers. The fusion proteins were cloned, expressed in Escherichia coli, characterized and compared to the native enzymes reagarding activity on polymers. Thc_Cut1+Hyd showed decreases activity on soluble substrates but increased activity on amorphous polyethylene terephthalate compared to the native enzyme. rNfpolyA showed no activity on polyamides but on a polyurethane/polyester copolymer where rNfpolyA+CBM and rNfpolyA+PBM showed higher activity. The study shows promising possibilities to enable an increase adsorption and hence improved enzymatic acitivty on insoluble polymers by fusion of binding domains to already active enzymes. The wide affinity diversity of binding domains in combination with the broad enzyme specificity enables limitless possibilities of enhanced enzymatic treatment by targeting enzymes to insoluble substrates.
Place, publisher, year, edition, pages
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-149344OAI: oai:DiVA.org:kth-149344DiVA: diva2:744661