A pectin methylesterase gene, pme-zj5a, from Aspergillus niger ZJ5 was cloned and high-level expressed in Pichia pastoris. The highest PME activity was 71.11 U/ml after induction with methanol for 20 h at 30 degrees C. The molecular mass of purified PME-ZJ5A was estimated to be 37 kDa by SDS-PAGE, and its K-m, V-max, and k(cat) values of PME-ZJ5A were determined to be 3.27 mg/ml, 5.36 mu mol/min/mg, and 2233 s(-1) with pectin. Purified recombinant PME-ZJ5A exhibited optimal activity at pH 3.8 and 45 degrees C. It retained more than 60% of its maximum activity at 10 degrees C. Moreover, recombinant PME-ZJ5A can increase the transmittance of pineapple juice by 60.8%, and increase the firmness of pineapple cubes nearly double when combined with CaCl2, which showed good potential in fruit processing. (C) 2018, The Society for Biotechnology, Japan. All rights reserved.