Oxidative Stress Response Of Phanerochaete Chrysosporium In Simulated Waste Water

The harm of heavy metals and organic pollutants to the environment has becomea global problem. In the field of wastewater treatment, the existing technologiesdepending on microorganisms can successfully remove the heavy metals and organicpollutants in the wastewater. Microorganisms adsorb heavy metals and degradeorganic matter， at the same time, these contaminants can induce microbial cell stressresponse and produce a large number of reactive oxygen species (ROS), whichproduces oxidative stress to cells, and even causes oxidative damage. As a result, it isnecessary to understanding the toxicity of the microbial contaminants and the microdefense mechanism of pollutants induced by microorganism.This paper explored the change of the active oxygen levels in Phanerochaetechrysosporium(P. chrysosporium) under the duress of cadmium (Cd(II)) and2,4-dichlorophenol (2,4-DCP). Oxidative stress effectin P. chrysosporium by thepollutants was illustrated through detecting the malondialdehyde (MDA) and thedynamic changes of the intracellular protein content. The change of superoxidedismutase, catalase activity, and combined with glutathione function were analysed byultraviolet and visible spectrophotometry and Bradford assa y was employed to discussthe regulating mechanism of the P. chrysosporium on Cd(II) and2,4-DCPintimidation.At low concentration treatment (5mg/L Cd(II),20mg/L2,4-DCP), the contentof intracellular ROS was significantly higher than the control group. While at highconcentration treatment (50,100mg/L of Cd(II),2,4-DCP respectively), intracellularROS content was lower than the control group. With5mg/L Cd(II) deal with bacteria,the content of MDA in P. chrysosporium increased slowly, and50mg/L for Cd(II)deal with bacteria, MDA content would be increased after decreased. Under thecontinuous induction with100mg/L2,4-DCP, the contentof MDA in P. chrysosporiumin8hours was less than that at the startof contact.In5mg/L of Cd(II), intracellular protein content increased with the increase ofcontact time, and achieved a higher value77.512μg/mL. At50mg/L Cd(II) and20mg/L of2,4-DCP, the content of intracellular protein was increasing followed bydecreasing with the contact time. In100mg/L of2,4-DCP,intracellular protein contentwas reducing with the increase of contact time.After the stress of Cd(II) and2,4-DCP, the antioxidant enzyme activity of SOD and CAT in P. chrysosporium increased to the peak during a short time. In4hours,SOD vigor reached13.264U/mg protein, CAT activity of4.710U in bacteria treatedwith100mg/L2,4-DCP. As the extension of time, the antioxidant enzyme systemenergy gradually decreased integrally. The enzyme activity of some experimentalgroup was significantly lower than that of the control, it was shown that theantioxidant enzyme activity was depressed at this time. After treating the P.chrysosporium with the concentration of Cd(II)(>5mg/L) and2,4-DCP (>20mg/L),the content of glutathione (GSH) reduced bythe increasing of type oxidizedglutathione (GSSG) and GSH/GSSG showed a trend of decrease.