The killer toxin of the halotolerant yeast Candida nodaensis

Abstract

In a previous survey, the halotolerant yeast Candida nodaensis was identified as one of the strongest killer strains, displaying an enhancement of killer action in the presence of salt (maximum activity detected at 2M NaCl). Results of nucleic acid extractions and curing experiments suggested that this zymocin might be encoded by a nuclear gene. The great majority of killer toxins are considered labile proteins, unfitted for biotechnological purposes. Preliminary experiments in order to characterise C. nodaensis zymocin showed that, besides keeping its biological activity at high NaCl concentrations, this killer factor is stable after incubation in a relatively broad range of temperature and pH values, either in the absence or in the presence of NaCl (1M).