Expression and characterization of a cutinase (AnCUT2) from Aspergillus niger

Cutin hydrolase (EC 3.1.1.74), an extracellular polyesterase found in pollens, bacteria and fungi, is an efficient catalyst that exhibits hydrolytic activity on a variety of water-soluble esters, synthetic fibers, plastics and triglycerides. Thus, cutinase can be used in various applications such as ester synthesis, bio-scouring, food and detergent industries. Ancut2 is one of five genes encoding cutinases present in the Aspergillus niger ATCC 10574 genome. The cDNA of Ancut2 comprising of an open reading frame of 816 bp encoding a protein of 271 amino acid residues, was isolated and expressed in Pichia pastoris. The partially purified recombinant cutinase exhibited a molecular mass of approximately 40 kDa. The enzyme showed highest activity at 40 degrees C with a preference for acidic pH (5.0-6.0). AnCUT2 showed hydrolytic activity towards various p-nitrophenyl esters with preference towards shorter chain esters such as p-nitrophenyl butyrate (C4). Scanning Electron Microscopy demonstrated that AnCUT2 was capable of modifying surfaces of synthetic polycaprolactone and polyethylene terephthalate plastics. The properties of this enzyme suggest that it may be applied in synthetic fiber modification and fruit processing industries.