Study On The Enhancement Of Dehydrocoenzyme Activator On Petroleum Hydrocarbon Degrading Compound Bacteria

In recent years,with the sustained and rapid development of China’s economy,the demand for crude oil and its products from all walks of life has increased.The serious pollution of soil caused by crude oil transportation and leakage has aroused widespread concern.Because of its advantages of simple operation,low cost,good effect,reliable environmental protection,on-site treatment and high public acceptance,biological method has become a hot spot in the remediation of oil contaminated soil.In this research,three strains of petroleum hydrocarbon degrading bacteria were selected and acclimated from the oil contaminated soil collected in Shengli Oilfield.The three strains were identified by 16S r DNA molecular biological technology.The results showed that strain T-1 was Achromobacter xylosoxidans strain,strain T-2 was Bacillus cereus strain,and strain T-5 was Pseudomonas aeruginosa strain.According to the growth and metabolism of three strains of bacteria and the degradation effect of petroleum hydrocarbon,an efficient petroleum hydrocarbon degradation compound bacterial agent was constructed.The mixture of strain T-1 and strain T-5 was selected with the volume ratio of 2:1.The results showed that the degradation rate of petroleum hydrocarbon by the compound bacterial agent was 26.39%in 7days.Based on the fact that dehydrogenase can activate the hydrogen atoms of petroleum hydrocarbons and transfer them to specific hydrogen receiving bodies,the oxidation and transformation of petroleum hydrocarbons can be realized.Water soluble vitamins are added to the bacteria as the coenzyme or auxiliary group of dehydrogenase,so as to improve the enzyme production activity of the oil hydrocarbon degrading bacteria,and then improve the degradation effect of petroleum hydrocarbons.The effects of the concentration of Na NO₃,（NH₄）₂HPO₄and growth factor on the degradation of total petroleum hydrocarbons were studied in this research.By variance analysis,R²=0.9902,P<0.05,the model was effective.According to the results of response surface optimization experiment,the dehydrogenase activator was composed of Na NO₃7 g/L,（NH₄）₂HPO₄1.0 g/L,riboflavin 6 mg/L and nicotinamide 6 mg/L.By applying dehydrogenation coenzyme activator to the compound bacterial agent for petroleum hydrocarbon degradation,the total bacterial concentration of the bacterial agent was increased in varying degrees,the dehydrogenase activity of the compound bacterial agent was increased from 25.84μg/m L·h to 30.83μg/m L·h,and the degradation rate of crude oil from Dongxin oil production plant of Shengli Oilfield was increased from 26.36%to 33.31%in 7 days.The results showed that coenzyme activator could promote the production of dehydrogenase and the degradation of petroleum hydrocarbons.Four pot experiments with different treatments were carried out to simulate the remediation of petroleum contaminated soil.After 60 days of remediation,the degradation rate of petroleum hydrocarbons in CK group was 39.80%,while in（BS+BA）group was 69.44%,and sphaerobacter,Streptomyces and Pseudomonas were the dominant genera.The results showed that the combined application of dehydrogenation coenzyme activator and petroleum hydrocarbon degradation compound bacteria could activate the synergistic effect of petroleum hydrocarbon degradation compound bacteria and indigenous microorganisms,and promote the microbial degradation of petroleum hydrocarbons in soil.