BATCH PHENOL DEGRADATION BY CANDIDA-TROPICALIS AND ITS FUSANT

Phenol degradation by Candida tropicalis and its fusant, which is prod uced using protoplast fusion as a selective technique, is evaluated un der batch and high concentration conditions. The respirometric data sh ow that oxygen uptake activities of both yeast strains peak at pH 7.0 and 32 degrees C, but the fusant is more active than the control strai n. Although the data show that both yeast strains are capable of susta ining discernible degradation in the presence of phenol inhibition, ho wever, the C. tropicalis fusant is capable of attaining better phenol degradation than the control strain and it is less susceptible to phen ol inhibition. Under the conditions tested, C. tropicalis is completel y inhibited at phenol concentrations greater than or equal to 3,300 mg /L, whereas for the C. tropicalis fusant complete inhibition is absent until phenol concentrations are greater than or equal to 4,000 mg/L. The observed cell yields of both yeast strains are virtually identical and remain fairly constant at approximately 0.5 mg MLVSS/mg C6H5OH (M LVSS: mixed liquor volatile suspended solids). (C) 1998 John Wiley & S ons, Inc.