Study On Producing Enzyme By The Northeast White-rot Fungi And Its Characteristics On PAHs Degradation

In recent years, with the rapid development of the industry science, industry and agriculture are also increasing, But a series of environmental problems has been Caused, at the same time,the environment of human living and social progress and development are threaten. Polycyclic aromatic hydrocarbons(PAHs) was a persistent organic contaminants in the environment. With the excessive use of fossil fuels, a great deal of PAHs is being released. PAHs is strong toxicity and more perniciousness, in addition it has stable properties in nature,which is difficult to be degraded. White rot fungi has highly ability of degrading, it depond on its non-specific extracellular degradation, which can degrade PAHs in a more effective way.In this paper,12local white-rot fungus which widespread grown in the forest northeast China were selected, through the screening test of degradation of PAHs, we eventually obtained highly efficient degrading bacteria-Pleurotus ostreatus, Polyporellus picipes, Pseudotrametes gibbosa, Ganoderma lucidum. Those anthracene degradation ratio after18days of inoculation exceed40%.In the study we optimized the laccase conditions of4kinds of white-rot fungus in carbon source, nitrogen source and pH by response surface analysis (RSA).Tu sum up, main components of Pleurotus ostreatus carbon source9.49g/L, nitrogen source0.93g/L, pH6.16; main components of Pseudotrametes gibbosa carbon source9.34g/L, nitrogen source0.39g/L, pH6.26; main components of Pleurotus ostreatus., carbon source36.85g/L, nitrogen source4.88g/L, pH6.1; the main components of Polyporellus picipes carbon source35.09g/L, nitrogen source3.94g/L, pH4.12.Different kinds of white-rot fungus has its own optimizing medium Condition. Optimal culture conditions of Polyporellus picipes were the temperature28℃, rotation speed160r/min, besides Optimal culture conditions of Pseudotrametes gibbosa was rotation speed130r/min.Using the optimal conditions for cultivating white-rot fungus, we researched on the process of growth and Lac secretion, different kinds of white-rot fungus differs in the period of Lac secretion, the period of growth, the maximum Lac. Polyporellus picipes has the maximum Lac, reached138764.2U/L, Pseudotrametes gibbosa has the maximum biomass237.05mg, the maximum biomass had appeared in day5for Ganoderma lucidum, the maximum Lac had appeared in day7for Pleurotus ostreatus. PAHs had promoted enzyme production, in the presence of anthracene Pseudotrametes gibbosa and Polyporellus picipes achieved the maximum Lac more earlier, meanwhile Pleurotus ostreatus and Ganoderma lucidum achieved the maximum Lac more later. Through measuring the degradation efficiency of PAHs by different kinds of white-rot fungus in the prophase, mid-term and anaphase. In every period of degradation all kinds of white-rot fungus have higher degradation efficiency in anthracene than pyrene; There are significant differences in differences periods of white-rot fungus. The degradation efficiency of anthracene and pyrene under Pleurotus ostreatus is30.12%and22.73%, the degradation efficiency of anthracene and pyrene under Pseudotrametes gibbosa is43.32%and24.26%, the degradation efficiency of anthracene and pyrene under Ganoderma lucidum is37.29%and38.35%, the degradation efficiency of anthracene and pyrene under Polyporellus picipes is94.76%and57.53%, To sum up, Polyporellus picipes has the maximum Lac In period of degradation, and its enzyme production has been promoted under anthracene, it also has s highest efficiency in the degradation of PAHs. In this study provide the scientific basis for the development and utilization of local white-rot fungi biological resources.