DefinePK

Abstract

Background:  The global spread of petrochemical and petroleum contamination, such as petroleum hydrocarbons (PHCs), is currently a significant environmental risk. The global biosphere is badly harmed by these pollutants, and biodiversity is significantly reduced. This study was to screen for xylanase synthesis in  Pseudomonas  spp. and evaluate its efficiency as a bioremediator in removal of hydrocarbons from hydrocarbon-contaminated soil. Methods:  Soil samples from Al-Dora oil plant Baghdad, Iraq, were cultured in nutritional agar medium containing 0.5% of corn cob xylan for determination of xylanase producers and measuring of xylanase activity, after that xylanaseproducers were identified. The xylanase was purified with DEAE-cellulose chromatography and the percentage of hydrocarbon degradation was calculated after treatment of hydrocarbon-contaminated soil with purified xylanase and detection of hydrocarbon degradation percentage. Results:  Pseudomonas putida  had the highest productivity for xylanase in comparison with other Pseudomonas species such as  Pseudomonas syringae  and  Pseudomonas aeruginosa , which revealed lower levels in xylanase production. Ammonium salt saturation and ion exchange chromatography were used to purify the xylanase enzyme on a DEAE-cellulose column with ultimate recovery of 43% and 4.3 fold of purification. With pure xylanase, hydrocarbons degraded over time, peaking after two weeks and then progressively diminishing. Conclusions:  Pseudomonas putida  is the best producer foe xylanase than other species. The purified xylanase led to removal of hydrocarbons from hydrocarbon-contaminated soil with time increasing manner until maximum removal after 15 days. Authors recommend using xylanase for cleaning up of oil-contaminated areas. Therefore, employing microorganisms as biological tools may be a more feasible way to handle one of the most serious issues in modern society which might be a more workable and affordable way to minimize waste and preserve natural resources. Keywords:  Petroleum hydrocarbons; Pseudomonas putida ; Xylanase; Bioremediation; Soil contamination