Degradation of tetracyanonickelate (II) by Cryptococcus humicolus MCN2

Abstract

A new yeast strain capable of degrading free and metallocyanides was isolated from coke-plant wastewater. The isolated strain designated MCN2 was identified as Cryptococcus humicolus by 26S rDNA sequencing and phylogenetic analysis. During growth of the isolate with KCN as a sole nitrogen source, formamide and formic acid were found as transient intermediates by [C-13]nuclear magnetic resonance analysis and ammonia accumulated as a final product in the culture medium. The strain MCN2 could degrade high concentrations of tetracyanonickelate (II) (K2Ni(CN)(4), TCN) up to 65 mM CN within 60 h when a sufficient amount of glucose was supplied as a carbon source. The maximal degradation rate of TCN was 2.5 mM CN h(-1) at the initial concentration of 51 mM CN. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.