Characterization of an Alkaline Thermostable Pectin Lyase from Newly Isolated Aspergillus niger_WHAK1 and Its Application on Fruit Juice Clarification

POTURCU K. , ÖZMEN İ. , Biyik H. H.

ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, vol.42, no.1, pp.19-29, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 1
  • Publication Date: 2017
  • Doi Number: 10.1007/s13369-016-2041-6
  • Page Numbers: pp.19-29


Pectin lyase degrades pectic substances that are complex polysaccharides of middle lamella and primary cell walls of plants. In this study, alkaline thermostable pectin lyase from Aspergillus niger strain_WHAK1 was produced on wheat bran and citrus pectin in submerged culture. Pectin lyase was purified by ammonium sulfate fractionation, gel filtration and ion-exchange chromatography, and 76.5 purification fold was obtained. Optimum pH and temperature values of pectin lyase were 8.0 and 40A degrees C at 60min, respectively. The enzyme was stable for 17 months at 4A degrees C. K-m and V-max values were found to be 5.2mg/mL and 0.2(mmol/min)(-1) mL, respectively. Molecular weight of pectin lyase was nearly 23.3 kDa. Effects on PL activity of metal ions (NaCl, KCl, CaCl2, MgCl2, CoCl2, CuCl2.H2O, FeCl3.6H(2)O, ZnSO4.7H(2)O, (NH4)(2)SO4, MnSO4), amino acids (l-tryptophan, l-cysteine hydrochloride monohydrate, l-arginine monohyd rate), ascorbic acid, citric acid monohydrate, EDTA and resorcinol were studied. The presence of FeCl3, CaCl2 and ascorbic acid significantly enhanced relative pectin lyase activity (%). The purified pectin lyase induced viscosity reduction in fruit juice samples, and it was effective for clarification of fruit juices. Pectin lyase showed substrate preference against fruit juice samples.