Thidarat Nimchua1, Douglas E. Eveleigh2, Usa Sangwatnaroj3, and Hunsa Punnapayak1. (1) Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Phayathai Road, Bangkok, 10330, Thailand, (2) Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, (3) Department of Materials Science, Faculty of Science, Chulalongkorn University, Phayathai Road, Bangkok, 10330, Thailand
Cutinase has a potential use for the modification of polyethylene terephthalate (PET) fabric its esterase activity modifying the fabric surface. Crude cutinase was produced by incubating F. solani PBURU-B5 in liquid mineral medium containing suberin (2 g/L). The enzyme was purified by sequential use of 50-80% ammonium sulfate precipitation, Hitrap Q FF, Hitrap Phenyl HP and HiPrep 16/60 Sephacryl S-200 High Resolution Chromatography. It was purified approximately 69 fold with overall 11% recovery and a specific activity of 137.5 U/mg. The enzyme was a single polypeptide about 18.8 kDa MW as determined by gel filtration and SDS-PAGE. The optimum pH was 9.0 at 45oC. Km value for p-NPB was 0.53 M-1. The enzyme activity was unaffected by the presence of metals with the exception of Cu++ (10 mM). Enzymatic modification of PET fabric using crude enzyme from PBURU-B5 showed hydrolysis of ester bonds of the PET fiber. After the enzyme treatment, the hydrophilicity of PET fabric increased as indicated from the enhanced water and moisture absorption. SEM showed surface modification. The treated fabric had enhanced dye uptake and a softer feel.