Biodegradation Of 4-Chlorophenol Effluents By Immobilized Fusarium SP.HJ01

Chlorophenol are widely distributed due to their common presence in the effluents of many industrial processes, including dye, pigment, preservative,herbicide, insecticide, fungicide industries. The application of immobilization techniques to chlorophenols effluents has been the subject of numerous investigations by environmental workers. In this research, Fusarium HJ01 has been applied to degrade 4-chlorophenol(4-CP). The speciality of HJ01 with potential for 4-chlorophenol degradation and its biodegradation enzyme is investigated. A new carrier, carboxymethylcellulose(CMC)-bentonite gel is studied and partially characterized physically and chemically. The fluidized bed reactor filled with CMC-bentonite gel-immobilized Fusarium HJ01 is constructed and operated to 4-chlorophenol treatment.The main conclusions of the research are as follows:1. Fusarium sp.HJ01 could grow using 4-chlorophenol as only carbon resource and energy. Additional carbon can speed the 4-chlorophenol biodegradation.In the condition of 1g·L-1sucrose, pH6,30℃, 100mg·L-1 of 4-chlorophenol is entirely degraded within 96h. The maximum of initial 4-chlorophenol concentration which this strain can endure is 100mg·L-1, when above the value,they are inhibited. the best nitrogen resource and phosphorus resource are NH4-N,H2PO4-P,respectively. The kinetic of 4-CP degradation accord with Haldane model when 4-CP is the sole carbon source and first order equation when sugar is added.2. This strain can exhibit activity of both chlorocatechol 1,2-dioxygenase (CC12O) and chlorocatechol 2,3-dioxygenase(CC23O) in free cell extracts. The activities of CC12O and CC23O reach the highest value which were 0.609U.mg-1 and 0.125U.mg-1 respectively when use 4-chlorophenol as single carbon resource. When CC12O make function, activity is optimal at pH6.8,50℃, while CC23O has a higher activity in alkalescence condition and is more stable at elevated temperatures when the optimal condition is pH8,60℃. Kinetics of enzyme-catalyzed reactions of CC12O and CC23O accord with The Michaelis-Menten equation.3. The density of CMC-bentonite gel are 1.00-1.07×103 kg·m-3, water content of the material is about 90%. The material appears a good character of 4-CP and cymene orange mass transportation.4,In the condition of the same biomass and solid to liquid ratio, the comparison of 4-chlorophenol degradation rate are CMC-bentonite gel-immobilized by embedment> CBC gel-immobilized by absorption> Ca-alginate-immobilized> free cells. In batch-recirculation mode experiment, the optimal air flow rate is 0.8L.min-1. In continuous flow process, the degradation rate obviously fell when the concentration of 4-chlorophenol in influent is larger than 100 mg·L-1. The reactor operated stably in 2 days under these conditions:concentration of 4-chlorophenol in influent is 50 mg·L-1, retention time 4h, air flow rate is 0.8L.min-1,the degradation rate in effluent maintained at about 65%, and the CMC-bentonite gel is not broken up, it shows that this carrier had some practical meaning in wastewater treatment. The kinetic of 4-CP degradation in different retention time accords with zero order equation.