Immunization of the industrial fermentation starter culture strain of Saccharomyces cerevisiae to a contaminating killer toxin-producing Candida tropicalis

Izgu F., Altinbay D., Derinel Y.

FOOD MICROBIOLOGY, vol.21, no.6, pp.635-640, 2004 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 21 Issue: 6
  • Publication Date: 2004
  • Doi Number: 10.1016/j.fm.2004.03.012
  • Journal Name: FOOD MICROBIOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.635-640
  • Middle East Technical University Affiliated: No

Abstract

K3 killer trait was introduced into the fermentation starter strain of Saccharomyces cerevisiae BSP 1 in order to construct immune industrial strain that produces K3 type killer toxin and was resistant to Candida tropicalis (K+) contamination. Protoplasts of respiration-deficient Rhodegrees strain of S. cerevisiae NCYC 761 (K3) and S. cerevisiae BSP 1 were fused. The resulting respiration-competent hybrid with K3 type killer activity was selected on media containing a non-fermentable carbon source and by a killer zone assay in a plate test, respectively. The fusant was similar to the parent strain in its fermentation and sugar utilization patterns, growth rate, dough-raising properties and osmotolerance. The newly constructed S. cerevisiae BSP 1 (K3) inhibited the growth of C tropicalis in a pH range from 3.5 to 5.0 and over a temperature range of 20-30degreesC. (C) 2004 Elsevier Ltd. All rights reserved.