Optimization Of Condition For Producing Laccase By White Rot Fungus And Its Application On PAHs Degradation

Polycyclic aromatic hydrocarbons(PAHs) was a persistent organic contaminants in the environment,which can lead to abnormality,cancer,mutation,aggrade in sorroundings and accumulated in organism easily,also it has harmful to human health and ecology system enormously.Microorganism of degradation PAHs has no second pollution,low cost and big area application.White rot fungus depend on its strong degradation enzyme,which can degrade particularly aromatic compound and ligin,especially ligin degradation enzyme.In this paper, chose two different white rot fungus to degrade PAHs,one was a white rot fungusPseudotrametes gibbosa isolated from northeast forest region,then optimized producing laccase condition,made it produced more laccase.Compared Pseudotrametes gibbosa with Pleurotus ostreatus of PAHs degradation effect in different fluid culture media with same culture conditions.Producing laccase of culture medium by Pseudotrametes gibbosa was optimized through rthogonal experiments,rthogonal experiments data was analyzed by using intuitionistic analysis and rang extremity anlysis,the scheme of optimum culture medium of producing laccase was showed as A₄B₂C₂D₂E₄,in which carbon source was corn flour,its concentration was on 10g/L,nitrogen source was NH₄Cl,its concentration was 0.44g/L,pH was 7.0. Influence sequence of every factor of Pseudotrametes gibbosa 's producing laccase was: R_e>R_d>R_b>R_a>R_C.pH was the most influential factor for produing laccase by white rot fungus,nitrogen concentration and nitrogen kind next to,carbon kind and carbon concentration finally.Using optimum liquid culture medium by orthogonal experiments,culture environment of Pseudotrametes gibbosa 's producing laccase was optimized,the result illustrated that the best producing laccase temperature and rotate was 25℃and 130r/min respectively.On the basis of optimal liquid culture medium and culture environment,laccase activity produced by Pseudotrametes gibbosa was highest as 2841.3U/L,which was five fold more than that one by TK liquid culture media in common study.At the same time,the result indicated that the peak of Pseudotrametes gibbosa 's producing laccase and the best value of growth weight was not synchronization.Anthracene and pyrene degradation rate by Pleurotus ostreatus were 18.76%and 30.12% respectively,the rate of Pseudotrametes gibbosa degraded anthracene and pyrene was 43.43%å’Œ24.26%。PAHs degradation effect by Pseudotrametes gibbosa was prior to Pleurotus ostreatus through comparison,culture medium seriously influent the degradation effect, laccase activity of Pseudotrametes gibbosa with optimum culture medium was 2841.36U/L, Pleurotus ostreatus was 471.15U/L,degradation effect has plus relativity with laccase activity, high laccase activity means best degradation effect.