Optimization of phenol degradation by Candida tropicalis Z-04 using Plackett-Burman design and response surface methodology

• Published in: Journal of environmental sciences (China) 2011, Vol.23 (1), p.22-30
• Main Authors: Zhou, Jiangya, Yu, Xiaojuan, Ding, Cong, Wang, Zhiping, Zhou, Qianqian, Pao, Hao, Cai, Weimin
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Biodegradation, Environmental; Candida; Candida tropicalis; Candida tropicalis - metabolism; Candida tropicalis Z-04; Charge coupled devices; Degradation; Design engineering; effluents; Environmental Restoration and Remediation - methods; experimental design; Granular materials; granules; Inoculum; Optimization; Phenol; Phenol - metabolism; phenol degradation; Plackett-Burman design; Regression Analysis; Reproducibility of Results; response surface methodology; temperature; Yeast; yeast extract; 中心复合设计; 优化策略; 响应曲面法; 实验设计; 热带念珠菌; 苯酚降解; 酵母提取物; 验证实验
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/S1001-0742(10)60369-5

Statistical experimental designs were used to optimize the process of phenol degradation by Candida tropicalis Z-04, isolated from phenol-degrading aerobic granules. The most important factors influencing phenol degradation （p 〈 0.05）, as identified by a two-level Plackett-Burman design with 11 variables, were yeast extract, phenol, inoculum size, and temperature. Steepest ascent method was undertaken to determine the optimal regions of these four significant factors. Central composite design （CCD） and response surface analysis were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum phenol degradation. The analysis results indicated that interactions between yeast extract and temperature, phenol and temperature, inocuhim size and temperature affected the response variable （phenol degradation） significantly. The predicted results showed that the maximum removal efficiency of phenol （99.10%） could be obtained under the optimum conditions of yeast extract 0.41 g/L, phenol 1.03 g/L, inoculum size 1.43% （V/V） and temperature 30.04℃. These predicted values were further verified by validation experiments. The excellent correlation between predicted and experimental values confirmed the validity and practicability of this statistical optimum strategy. This study indicated the excellent ability of C. tropicalis Z-04 in degrading high-strength phenol. Optimal conditions obtained in this experiment laid a solid foundation for further use of this microorganism in the treatment of highstrength phenol effluents.