Biodegradation of 2,6-ditert-butylphenol by immobilized microorganism strains

• Published in: Journal of environmental sciences (China) Vol. 18; no. 2; pp. 369 - 372
• Main Authors: Zhang, Ya-lei, Zhang, Zhi-gang, Xu, De-qiang, Qiang, Zhi-min, Li, Guang-ming, Zhao, Jian-fu
• Format: Journal Article
• Language: English
• Published: Key Laboratory of Yangtze Water Environment of Ministry of Education, Tongji University, Shanghai 200092, China%School of Life Science, Fudan University, Shanghai 200433, China%Department of Civil, Architectural and Environmental Engineering, University of Missouri-Rolla, Rolla, MO 65409, USA%State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China 2006
• Subjects: 合成工艺; 固定机制; 微生物; 生物降解; microorganism strains; biodegradation; 2,6-ditert-butylphenol; immobilization
• ISSN: 1001-0742; 1878-7320
• DOI: 10.3321/j.issn:1001-0742.2006.02.029

2,6-Ditert-butylphenol （2,6-DTBP） is a major organic contaminant presenting in acrylic fiber manufacturing wastewaters. This compound is of high bio-resistance due to its complex structure which consists of one phenol group and two highly branched tert-butyl groups. This research attempted to improve the biodegradation efficiency of 2,6-DTBP through various strain immobilization methods. The stratified immobilization can settle oxygen transmission in the single microorganism immobilization, and can realize two-process reaction in the single device by choosing two symbiotic microorganisms. Two effective strains, named F-1-4 and F-3-4, which were screened out in our previous work, were used to degrade 2,6-DTBP after being immobilized in calcium alginate gel. Results indicate that the substrate removal efficiency of various immobilization methods follows the order： stratified 〉 single F-3-4 〉 mixed ≈single F-1-4. The immobilized biodegradation capacity was higher than the free one. After an incubation time of 12 d, 91% of 2,6-DTBP could be degraded by the stratified immobilization method, compared to 79% achieved by the mixed immobilization method with an initial 2,6-DTBP concentration of 100 mg/L. The stratified immobilization satisfies the oxygen demand nature of the aerobic F-3-4 and the facultative F-1-4, thus yielding the highest degradation efficiency. Both the outer layer strain F-3-4 and the inner layer strain F-1-4 can grow actively on the substrate of 2,6-DTBP, as illustrated by SEM images. This study shows that the highly bio-refractory compound, 2,6-DTBP, can be effectively degraded using appropriately inunobilized microorganism strains.