Biodegradation of Gaseous Chlorobenzene by White-rot Fungus Phanerochaete chrysosporium

Objective To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene. Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles. A certain amount of chlorobenzene was injected into the headspace of the bottles under different conditions. At a certain interval, the concentrations in the headspace were analyzed to evaluate the degradation of chlorobenzene by P. chrysosporium. Results The degradation effects of P. chrysosporium on chlorobenzene under different conditions were investigated. The difference in the optimum temperature for the growth of the fungi and chlorobenzene degradation was observed. The data indicated that a lower temperature （28℃） would promote the degradation of chlorobenzene than the optimum temperature for the growth of the fungi （37℃）. A low nitrogen source concentration （30 mg N/L） had a better effect on degrading chlorobenzene than a high nitrogen source concentration （higher than 100 mg N/L）. A high initial concentration （over 1100 mg/m3） of chlorobenzene showed an inhibiting effect on degradation by P chrysosporium. A maximum removal efficiency of 95% was achieved at the initial concentration of 550 mg/m3. Conclusion P. chrysosporium has a rather good ability to remove gaseous chlorobeuzene. A low nitrogen source concentration and a low temperature promote the removal of chlorobenzene by P. chrysosporium. However, a high initial chlorobenzene concentration can inhibit chlorobenzene degradation.

白腐真菌生长条件及其代谢动力学模型(英文)

To investigate the growth conditions of white-rot fungus and simulate its metabolism kinetic models, the rules how the factors such as biomass, culture fluid, pH value, glucose consumption and exopolysaccharides generation, etc., changed during the batch culture process of white-rot fungi by using an air-lift fermenter, as well as metabolic kinetics of white-rot fungi were studied. Based on Logistic equation, Luedeking-Piret equation and experimental data, the correlation model parameters of mycelia biomass, glucose consumption and exopolysaccharide generation were obtained and found to be change with time in metabolism process. Detailedly, μm=0.071 8 h-1,α= 0.831 8 g/(g·h), β= 0.002 g/(g·h), b1=0.016 3 g/(g·h) and b2=3.023 3 g/(g·h). Hence the mycelial growth kinetic model, exopolysaccharide generation kinetic model and substrate consumption kinetic model which describe fermentation process of white-rot fungi were established. Meanwhile, the experimental data were verified by this model, and a good fitting result with an average relative error less than 10% between the data obtained from experiments and the model was yielded. The results show that these models can predict the growth and metabolic rules of white-rot fungus, the fermentation process of exopolysaccharides and the kinetic mechanism of white-rot fungus accurately.

黄孢原毛平革菌产木素过氧化物酶发酵条件的优化

对白腐菌(Phanerochaete chrysosporium)产木素过氧化物酶的发酵条件进行了研究。在单因素试验的基础上用正交试验进行工艺参数的优化。结果表明,木素过氧化物酶的最佳培养条件为培养13 d、接种0.5 mL,料液比1∶2.5(W/V,g∶mL)、培养温度25℃,酶活为771 U/mL。

Conditional Optimization of Laccase Production by Whiterot Fungi through Fermentation

Phanerochaete chrysosporium was selected as the production strain of laccase,and the effects of stirring speed,ventilation volume,culture temperature,inoculation amount and initial p H of medium on laccase production by liquid fermentation in cylinder were studied. On the basis of single factor test,an orthogonal test was carried out to find optimal conditions for laccase production P. chrysosporium through liquid fermentation. These results showed that the stirring speed of fermentation cylinder had the highest effect on laccase production,and the optimal conditions were shown as follows： the temperature at 28 ℃,the rotating speed at 300 r/min,the ventilation volume of 5 L/min（ ventilation ratio of 1.0 vvm）,the initial p H of medium of 5,and the inoculation amount of 15%,which gave the highest laccase level of 14. 86 U/ml.