Thermostable alkaline protease produced by an Aspergillus niger strain


Coral G., ARIKAN B., Ünaldi M., Güvenmez H.

Annals of Microbiology, vol.53, no.4, pp.491-498, 2003 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 53 Issue: 4
  • Publication Date: 2003
  • Journal Name: Annals of Microbiology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.491-498
  • Keywords: Alkaline protease, Aspergillus niger
  • Hatay Mustafa Kemal University Affiliated: Yes

Abstract

A thermostable alkaline protease was isolated from the Aspergillus niger Z1 strain in a liquid Czapek Dox medium, containing casein (1% w/v) as the sole nitrogen source. Enzyme extract was subjected to electrophoresis in SDS-polyacrylamide gel. Two protein bands were seen on polyacrylamide gel. Active enzyme was visualized in a zymogram and protease activity exhibited a molecular mass of 68 kDa on SDS-polyacrylamide gel. The optimum pH for activity was found to be 9.0. The temperature optima of the enzyme was found to be 40°C at pH 9.0 and it remained stable up to 90°C, with 48.4% of the original activity retained after heat treatment at 90°C for 15 min. Proteolytic activity was inhibited by PMSF, but slightly inhibited by SDS.