BIODEGRADATION OF PHENOL WITH CANDIDA TROPICALIS ISOLATED FROM AEROBIC GRANULES

摘要

In this study, strains were isolated via selected medium from aerobic granules acclimated with phenol synthetic wastewater, which could use phenol as the sole carbon and energy source. Among of them, YA-3 was confirmed to possess the highest phenol tolerance and degradation rate, and identified as Candida tropicalis with the phylogenetic analysis of 26S rDNA ITS sequences. To investigate its degradation properties of phenol, inoculum volume, pH, temperature and second carbon source were optimized in phenol degradation experiment, and the optimal conditions were listed as inoculum ratio 3-7% (V/V), pH 4.0-8.0 and 25-35℃. Appropriate dosage of glucose could speed up the proliferation of Candida tropicalis, thus promoted the degradation of phenol. According to the degradation of phenol at different initial concentration, the inhibitory kinetics of phenol degradation was simulated using Haldane model. The model's kinetic parameters were evaluated as the maximum specific growth rate μ_(X,max)=0.418hr~(-1), the half-saturation coefficient K_S = 74.69mg/L, the inhibition coefficient for cell growth K_1 =432.38mg/L, and the maximum specific phenol degradation rate was 0.447hr~(-1). These results demonstrated that Candida tropicalis had high feasibility and engineering value, which could be used as bioaugmentation consortia to shorten the acclimation phase of aerobic granules or remedy phenol contamination in situ.