Research On Screening And Characteristics Of Petroleum Hydrocarbon Degrading Fungi In Oily Sludge

With the continuous development of the oil industry,oil pollution problems caused by oil extraction,transportation,and processing are increasing.The types,yields and scope of contaminated soil caused by oil are also increasing in varying degrees.Among them,oily sludge is a type of mixed oily solid waste produced in the production or transportation of oil fields.It has a large output and high oil content.If it is not handled properly,it will cause great harm to the environment.At present,harmless and resource disposal of the oily sludge has not been studied and implemented by most oil field systems.In this paper,the oily sludge of an oily sludge treatment plant in Ansai area of Changqing Oilfield was selected as the research object.Six fungi with petroleum hydrocarbon degrading ability were screened,and their growth characteristics and degradation characteristics were studied in depth.Concluded asfollow:1)Six strains of petroleum hydrocarbon degrading fungi were selected from the oily sludge of Changqing Oilfield in Ansai area and they were numbered:F-2,F-3,F-4,F-5,F-7,F-8.They were identified that F-2,F-4 and F-5 belong to the genus Sphaerospora sp.,F-3 belongs to the genus Spicola sp.,and F-7 belongs to the genus Gliocladium sp.,F-8 belongs to the genus Penicillium sp..2)The effect of environmental conditions on the growth of the strain was discussed.F-2,F-5,F-7,and F-8 had a wide range of adaptability to p H,and could grow stably in the environment of p H 5-9.In the temperature range of 20-50℃,F-3 and F-8 grew well and had strong tolerance to temperature.The other strains were more sensitive to temperature changes.F-2,F-3,F-7,and F-8 had a large demand for oxygen and the optimum speed was 160 r/min.Glucose was the most easily utilized carbon source for F-2,F-3,F-5 and F-8.Among them,the optimum concentration of F-2,F-3 and F-8 was 2%,and the optimum concentration of F-5 was 3%.Sucrose was the most easily available carbon source for F-4 and F-7,of which the optimum concentration of F-4 was 2%,and the optimum concentration of F-7 was 3%.3)The analysis of the factors affecting the degradation of petroleum hydrocarbons by fungi showed that F-7 had the best tolerance to petroleum hydrocarbon concentration.When the petroleum hydrocarbon concentration was 9 g/L,its degradation rate could reach more than50%.F-3 had the weakest tolerance to petroleum hydrocarbons.Most strains showed good petroleum hydrocarbon degradation ability when KNO₃was used as nitrogen source and K₂HPO₄+KH₂PO₄was used as compound phosphorus source.Among them,F-2,F-3,F-4 and F-5 were more sensitive to the change of nitrogen source concentration.Except for F-7,the other strains were more sensitive to the change of phosphorus source concentration.The optimal inoculum of F-2,F-4,F-5 and F-7 was 3%.4)GC-MS component analysis results showed that F-2,F-3,F-4 and F-5 had obvious degradation effects on short-chain alkanes;F-7 had the widest range of carbon chain utilization and the best degradation effect.The degradation effect of F-8 was second only to F-7.The study on the laccase activity of the strains found that the laccase activity of F-7 and F-8 had a significant correlation with the degradation rate of petroleum hydrocarbons,while the correlation between the other strains was not obvious.