高效降酚真菌的分离、鉴定及特性研究

Study on Isolation,Identification and Characteristic of Phenol Degradation Fungus

苯酚和酚类化合物是环境中常见的有毒污染物。利用富集、筛选和纯化的方法,从山西省太谷县圣源污水处理厂曝气池中分离得到一株能以苯酚为唯一碳源生长的苯酚降解真菌GY8。采用rDNA ITS区序列分析,鉴定该菌株为热带假丝酵母属。该菌株在48 h内对1.0 g/L苯酚降解率接近100%,在以苯酚为唯一碳源的培养条件下能够耐受1.8 g/L的苯酚。同时,通过设定不同pH值、不同接种量、不同溶解氧条件,对该菌降解特性进行研究。结果表明,该菌最适pH值为6.5,随着接种量的增加降解能力增强,5%接种量可使1.0 g/L苯酚在24 h内降解率达90%以上,有氧条件更利于苯酚的降解。研究表明,热带假丝酵母GY8对处理含酚废水具有良好的应用前景。

Phenol and phenolic compounds are one of the most prevalent toxic environmental pollutants. In this paper, by using the enrichment, selection and pure culture, a phenol-biodegrading fungus strain, designated as GY8, was isolated from the aeration tank of Taigu wastewater treatment plant. The strain was able to utilize phenol as a sole carbon source. Analysis of the r DNA ITS sequence showed that it belonged to the genus of Candida tropicalis. The strain could degrade almost 1.0 g/L of phenol within 48 h and could tolerate up to 1.8 g/L phenol by utilizing it as the sole carbon source. Various parameters were investigated for the maximum biodegradation of phenol by setting different levels of pH, inoculum size, and dissolved oxygen conditions. The results showed that the maximum growth and phenol degradation of strain could be obtained under the optimal condition of pH 6.5. Increasing inoculum size could accelerate the degradation rate. The rate of phenol degradation at concentration of 1.0 g/L reached above 90% at 5%（v/v）inoculum size within 24 h. The dissolved oxygen could accelerate the rate of phenol degradation. It is concluded that the organism i.e. Candida tropicalis GY8 has potential prospect in bio-treatment of phenol-containing wastewater.