Tailoring cutinase activity towards polyethylene terephthalate and polyamide 6,6 fibers

• Published in: Journal of biotechnology Vol. 128; no. 4; pp. 849 - 857
• Main Authors: Araújo, Rita, Silva, Carla, O’Neill, Alexandre, Micaelo, Nuno, Guebitz, Georg, Soares, Cláudio M., Casal, Margarida, Cavaco-Paulo, Artur
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 10.03.2007; Amsterdam Elsevier; New York, NY
• Subjects: Adsorption; Biocatalysis; Biological and medical sciences; Biotechnology; Biotransformation; Caprolactam - analogs & derivatives; Caprolactam - chemistry; Caprolactam - metabolism; Carboxylic Ester Hydrolases - chemistry; Carboxylic Ester Hydrolases - genetics; Carboxylic Ester Hydrolases - metabolism; Cutinase; Fundamental and applied biological sciences. Psychology; Fusarium - enzymology; Fusarium - metabolism; Fusarium solani pisi; Models, Molecular; Mutagenesis, Site-Directed; Polyamide 6,6; Polyester; Polyethylene Terephthalates - chemistry; Polyethylene Terephthalates - metabolism; Polymers - chemistry; Polymers - metabolism; Site-directed mutagenesis; Succinates - metabolism; Polyamide 6,6; Cutinase; Polyester; Biocatalysis; Site-directed mutagenesis; Polyethylene; Ester polymer; Fiber; Site directed mutagenesis
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2006.12.028

Cutinase from Fusarium solani pisi was genetically modified near the active site, by site-directed mutagenesis, to enhance its activity towards polyethylene terephthalate (PET) and polyamide 6,6 (PA 6,6) fibers. The mutations L81A, N84A, L182A, V184A and L189A were done to enlarge the active site in order to better fit a larger polymer chain. Modeling studies have shown enhanced free energy stabilization of model substrate tetrahedral intermediate (TI) bound at the enzyme active site for all mutants, for both model polymers. L81A and L182A showed an activity increase of four- and five-fold, respectively, when compared with the wild type, for PET fibers. L182A showed the one- and two-fold higher ability to biodegrade aliphatic polyamide substrates. Further studies in aliphatic polyesters seem to indicate that cutinase has higher ability to recognize aliphatic substrates.