Biodegradation of phenol and m-cresol by mutated Candida tropicalis

摘要

The phenol and m-cresol biodegradations were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis.The results showed that C.tropicalis exhibited the increased capacity of phenolic compounds degradation after laser irradiation.It could degrade 2600 mg/L phenol and 300 mg/L m-cresol by 5% inoculum concentration,respectively.In the dual-substrate biodegradation system,0-500 mg/L phenol could accelerate m-cresol biodegradation,and 300 mg/L m-cresol could be completely utilized within 46 hr at the presence of 350 mg/L phenol.Besides,the maximum biodegradation of m-cresol could reach 350 mg/L with 80 mg/L phenol within 61 hr.Obviously,phenol,as a growth substrate,could promote CTM 2 to degrade m-cresol,and was always preferentially utilized as carbon source.Comparatively,low-concentration m-cresol could result in a great inhibition on phenol degradation.In addition,the kinetic behaviors of cell growth and substrate biodegradation were described by kinetic model proposed in our laboratory.