Background and Aim: Dielectric Barrier Discharge (DBD) cold plasma has efficient antibacterial activity on bacterial contamination at a short period of time and confirms its potential for routine used in clinical environment biodecontamination as an alternative to conventional disinfectant methods of water treatment. The goal of this study is to evaluated in vitro effectiveness of DBD cold plasma on clinically important opportunistic pathogens that identified from water samples which were: Legionella E.meningosepteca and S. paucimobilis growth and to study DBD effectiveness on survival bacterial cell after treatment. Methodology: 100-200 cfu/ml of Seven different environmental bacterial isolates belong to Legionella (4 isolates) E.meningosepteca(one isolate) and S. paucimobilis (two isolates) at species were subjected to eleven different exposure time of DBD cold plasma treatment rang from 15Sec to 300 Sec, and plated on suitable agar media. Results were quantified by viable count.

Lignin peroxidase produced from A. terreus SG777 precipitated with 80% ammonium sulfatesaturation then desalting by dialysis against Tris buffer solution and partially purified by ionexchange chromatography using DEAE- cellulose.The specific activity reached 56.67U/mg withpurification fold was 5.4 times and 13.7% recovery. The optimum pH for activity and stability was(3). The maximum activity was observed at 40°C and the enzyme maintained the activity when itwas incubated at (25-35)˚C.Degradation of poly aromatic hydrocarbons when incubated with 65.51 U/ml lignin peroxidaseat (40°C) for 4 hr compared with the Refinery treatment. Results showed (97.54%) removalefficiency of Di benzo (a, h) anthrancene by lignin peroxidase, while only (54.37%) was treated byRefinery treatment. Flourene and anthrancene degradation (95.98%) and (83.51%) respectively,while the flourene and anthrancene degradation treated by Refinery treatment only 84.51% and(46.83%) respectively.The aim of this study was degradation of poly aromatic hydrocarbons by using partialpurification lignin peroxidase.