Studies On Biodegradation Of Pentachlorophenol In Soil By Phanerochaete Chrysosporium Burdsall

The article studied the biodegradation of pentachlorophenol-contaminated soil by typical white rot fungus Phanerochaete chrysosporium .The influence of three control parameters ( inoculation amount, temperature and soil moisture) on the growth of P. chrysosporium and PCP biodegradation efficiency were examined . The correlations of both PCP biodegradation with fungus growth and peroxidases activity and fungus growth to lignin peroxidases (LiP) activity were analyzed . Kinetic equations of different initial concentration PCP degradation were gived . hi the end , tested the PCP degradation activity of P. chrysosporium under unsterilized soil conditions . The results obtained are as follows:Research of method to measure PCP in soil . Based on the safranic-T spectrometer method to directly extract PCP from soil samples and determine PCP concentration . Data showed that when PCP concentration in soil was 50-100 mg/kg , the recovery rate was 85.50 ~ 95.38% , and the sensitivity was O.Olmg/kg by using this new method . The method which needn't large-scale instrument is not only easy to do but exact and reliable.Studies PCP degradation conditions in sterilized soil by P. chrysosporium . Results indicated that at the test concentration the optimum parameters for obtaining the maximum degradation rates for PCP are 0.10 ml/g in inocubation amount, 4:1 for soil/ water ratio and 30-37℃ in temperature , degradation rate was the highest in this condition with the values 91.64% on the 30th day . At the same time fungus growth showed that the ideal conditions for P. chrysosporium growth are 0.10 ml/g in inocubation amount, 4:1 for soil/ water ratio and 37℃ in temperature .The results of correlation analysis among the PCP degradation, P. chrysosporium growth and enzyme activity are shown below: 1) The correlation is significant between thedegradation of PCP and fungi growth with a lower (50.05mg/kg) initial PCP concentration and there is no significant relevancy to peroxidases activity. 2)When initial PCP concentration is at a higher ( 175.72mg/kg ) level, PCP degradation is markedly relevant with LiP3) In a moderate PCP level ( 87.40mg/kg and 145.94mg/kg), PCP degradation is relevant with MnP, however. 4) In a moderate PCP level ( 87.40mg/kg and 145.94mg/kg), fungi growth is relevant to MnP and not relevant to LiP . But when PCP concentration is lower or higher, the analytical results is reverse .Degradation of different initial PCP concentration conformed to one-rate kinetic equation. At PCP concentration of 50.05 ~ 175.72 mg/kg , biodegradation rate constants reduces with increasing of PCP concentration , which indicated that high concentration of PCP can signficantly restrain the biodegradation by P. chrysosporium .In unsterilized soil, effect of inocubation amount and temperature on PCP degradation with P. chrysosporium are as follows: at inocubation amount of 0.15ml/g soil , P. chrysosporium grew more rapidly than which at lower inocubation amount . Within 25 days, the amount of P. chrysosporium increased to 1.2 ×105cfu/g soil , but the fungi seriously dead in growth anaphase. Influence of inocubation amount on PCP degradation in unsterile soil were similar with that in sterile soil. The optimum temperature for growth of P. chrysosporium and PCP biodegradation was the same 37℃. In inocubation amount of 0.101ml/g soil and temperature of 37℃, the rate of PCP degradation was 68.81% within 65 days, which showed the large potential ability of P. chrysosporium to degrade PCP.