懸浮態與固定化細胞同時降解酚及水楊酸之動力學

Dynamics of Simultaneous Degradation of Phenol and Salicylate Using Freely Suspended and Immobilized Cells

蔡尚原(Shang-Yuan Tsai)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(2004年)

摘要

工業廢水中含有許多酚化合物，如不加以處理而直接排放，會對整個生態環境造成嚴重的污染，所以本研究以具降解酚和水楊酸能力之細菌Pseudomonas putida 進行降解，以期能夠將酚和水楊酸處理到合乎於排放標準。
Pseudomonas putida同時降解酚與水楊酸時，在總莫耳濃度相同時，水楊酸比例越高所需降解的時間也越久。而用酚預培養菌液的降解所需的時間比用水楊酸預培養的久，尤其是當水楊酸濃度比例較酚高時。
動力學方面，Pseudomonas putida降解酚和水楊酸皆有基質抑制的現象，Pseudomonas putida對酚的降解能力較水楊酸佳，受酚的抑制較水楊酸小，但是對水楊酸的親和力較好一些。整體而言，Pseudomonas putida比較喜歡降解酚而比較不喜歡降解水楊酸。單成分和雙成分動力參數大致上相互符合，曲線擬合(Curve fitting)的最小標準平方差皆在0.92以上。
疏水性中空纖維薄膜的降解實驗中，酚由廢水端質傳至菌液端速率緩慢，而水楊酸則是完全不會質傳至膜的另一測，水楊酸須等菌液端降解完酚後質傳至廢水端時，才會開始降解。親水性中空纖維膜實驗中，酚與水楊酸都會質傳至菌液端且速率皆有所提昇。而起始濃度較高時，雖然所需降解完全的時間較久但依然能完全降解。整體而言、親水性中空纖維膜很有潛力運用在連續操作，尤其是在基質濃度夠高而毒性不是很高時。
最後，結合質傳理論與動力的結果，預測細胞於中空纖維中降解酚與水楊酸。在總基質濃度37.20 mM以下時，降解理論線結束時間，與實驗點相當吻合。

關鍵字

懸浮態 ； 固定化細胞 ； 降解 ； 酚 ； 水楊酸 ； 中空纖維薄膜 ； 動力

並列摘要

Phenolic compounds are often encountered in industrial effluents. The discharge of wastewater without proper treatment poses serious environmental problems. A Pseudomonas putida strain capable of degrading phenol and salicylate in wastewater was utilized to investigate the dynamics of phenol and salicylate removal and, hopefully, to meet the standard of discharge.
When the total molar concentration of phenol and salicylate was kept constant it took a longer time for biodegradation of the mixture by Pseudomonas putida when the fraction of salicylate was high.
The kinetic studies have shown that both phenol and salicylate inhibited the growth of Pseudomonas putida. In addition the biodegradation of phenol was faster than salicylate, and the cells showed a better affinity to salicylate. Salicylate inhibited the culture to a greater extent than phenol. It was concluded that the culture preferred to biodegrade phenol inspite of the cells being pre-cultured with salicylate. The kinetics parameters were nearly the same for the biodegradation of single and mixed substrates. All the correlation coefficient R2 were above 0.92.
In hydrophobic hollow fiber modules, the mass transfer of phenol from wastewater tank to cell medium tank was slow and there was no mass transfer for salicylate. After phenol was biodegraded to zero level, the cells were transferred to the wastewater tank and salicylate was then biodegraded. In hydrophilic hollow fiber modules, salicylate could pass through the membrane and the mass transfer of phenol from wastewater tank to cell medium tank was faster than hydrophobic. Hydrophilic fibers are more promising for continuous biodegradation, especially when the substrates were not so toxic and their concentrations were high enough.
At last, we combine kinetic results and mass transfer theory for prediction the dynamic of substrate degradation and cell growth in hollow fiber. By comparing modeled line and experimental data at a total substrate concentration below 37.20 mM, the times required for complete biodegradation were nearly the same.

並列關鍵字

Freely Suspended ； Immobilized Cells ； Degradation ； Phenol ； Salicylate ； Hollow fiber membrane ； Kinetic ； Dynamics

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