Researches On Promotion Biodegradation Of Phenol By Chloroperoxidase&It’s Kinetics

Phenol was a kind of commonly raw material in the modern chemical industry,it was producted more than1.8million tons in one year. At the same time, there wasa large number of phenol wastewater discharge into the environment due to produceand consume in the process. Because of it’s lively chemical properties and stabilitystructure of benzene, phenol has become a toxic and harmful typical pollutants in theenvironment. Aerobic biological oxidation of phenol was a main metabolic pathways.In these pathways, phenol hydroxylase (PHO), catechol1,2-oxygenase (CatA) andcatechol2,3-oxygenase (CatO2ase) were the speed restriction enzymes in the phenoldegradation process. Because most of these enzymes were inducible enzyme, somicroorganism bio-synthetic these enzymes would take a long time lag, it will delaythe oxidation of phenol, it would affect the removal efficiency of phenol inwastewater. In this paper, according to the principle of co-metabolism of phenoldegrading strain, some strains with PHO, CatO2ase or CatA oxygenase enzymeswere screened. Using immobilization CPO and phenol degradating strainsco-oxidated phenol, established a efficient enzyme-bacteria phenol compounddegradation system,it can promote the bio-oxidation of phenol pollutants and thebiochemical removal, improved traditional way of phenol degradation.There were some results as following from the paper:1. Adding catechol and HMS or MA as co-metabolizing material of phenoldegradation can induced the different categories of oxygenase microbial in thesludge, From the domesticated sludge we have separated2highly active phenoldegradation strains L2and L6. Identified L2strain was Delftia sp., have CatA, L6isstrain was Sphingomonas sp., has CatO2ase; At the same time, the experiment foundthat added catechol can increase the speed of oxygenase synthesis, but also caninhibit the synthesis of PHO, reduce the oxidation of phenol generated the speed ofcatechol.2. Using hydrophilic polymer PEG6,000, the trace CPOin the fermented liquidcan precipitated in a high degree of saturation (NH4)2SO4.It can be extracted highpurity CPO with low cost, high recovery rate of by phosphate solution of sediment.CPO was immobilized by the composite carrier with sodium alginate and carrageenan, and successfully applied to the biological phenol oxidation process. Under the optimization condition with40℃, pH6.5, H2O210mg/L,10g/100ml immobilized CPO,500mg/L and1000mg/L phenol conversion rate reached86.57%and83.83%in2h, respectively. The chemical activity of phenol can quickly passivation by the immobilized CPO, the speed of phenol oxidized to catechol was increased, and the oxygenase induced was too, it improved the efficiency of phenol biodegradation.3. The composition of immobilized CPO, L2&L6compound strains and the conditions of the degradation of phenol was optimized using response surface analysis experiment design method, the results show that the enzyme-bacteria compound system with10g/100mL immobilized CPO and quantity of0.75%(v/v), the initial pH7.1, phenol concentration of500mg/L, yeast extract and200mg/L,2.5mg/L FeSO4, catechol200mg/L,the fluid volume75mL/250mL and L2and L6standard bacteria suspension according to1:1(v/v) can converted97.87%500mg/L phenol in16h, and The initial rate was only91.78%, increased more6.1%. Complete degradation time ahead of the more than4h, and COD remove more than8h ahead of schedule. Adding1%of sucrose, glucose and galactose and so on supplementary carbon source of enzyme-bacteria compound system of phenol degradation has a further promote role.4. That the intermediate of phenol conversion by CPO was catechol have been verified from the experiments. It was helpful to form co-substrates effect, and improved to adapt to the concentration of phenol for the growth of bacteria. From the experimental results,within100-1200mg/L phenol concentration range respectively, kinetics model shows that:(1) Haldane equation for the conversion of phenol with single immobilized CPO was:q=-1Haldane equations of degradation of phenol with synergetic degradation of co-strains was:(3) Haldane equation of composite degradation of phenol with combination Enzyme-strains System is: R2=0.9617.The fitting degree of all the3experimental results was higher, and among them, the enzyme-bacteria composite system than the largest degradation rate (qmax=1.95X10-4h-), the constant matrix is low(ks=1.0501mg/L), the substrate inhibition constant is higher(KI=5.1272mg/L). It was proved the combination Enzyme-strains System response speed, high affinity for phenol, phenol of high depth, strong inhibition, these parameters represent the build of the enzyme-bacteria biodegradation has obvious advantages,provides a new model for phenol biodegradation.