A biochemical characterisation of the rhodanese enzyme in different strains of Trichoderma was carried out in this study. The predominantly extracellular activity of this enzyme from Trichoderma was evaluated and the kinetics of the rhodanese enzyme reaction, including pH and temperature profiles, were assessed. Studies on the rhodanese enzyme from other systems have been compared with the results of this study. The kinetics of rhodanese in certain Fusarium strains, previously reported to degrade cyanides, were also analysed and compared to the enzyme from the Trichoderma. The rhodanese enzyme in all the Trichoderma strains demonstrated a broad pH optimum generally in the range from 8.5 to 11.5, along with a wide temperature optimum of 35-55degreesC. The K-m(CN) and V-max values ranged from 7 to 16 mM and from 0.069 to 0.093 mumole ml(-1) min(-1) mg protein(-1), respectively, between the selected strains of Trichoderma. (C) 2003 Elsevier Science Inc. All rights reserved.