Study On The Effect And Mechanism Of Surface Hydrophobic Strain Combined With Lipophilic Nutrient To Degrade Marine Oil Slick

The surface hydrophobicity of microorganisms is one of the main factors affecting their ability to absorb and degrade hydrophobic organic substances.Improving the surface hydrophobicity of microorganisms can help them adhere to the surface of petroleum hydrocarbons,thus effectively reducing the mass transfer distance of petroleum hydrocarbons and improving their bioavailability.In this paper,22 strains of oil-degrading bacteria were screened from the surface seawater polluted by oil near Dinghai Port in Zhoushan City through enrichment culture,separation and purification,and the surface hydrophobicity was determined respectively.Three strains with high surface hydrophobicity were selected for physiological and biochemical identification and 16S r RNA gene sequence evolution analysis.The main research contents of this paper are as follows:(1)In order to improve the adhesion ability of petroleum degrading bacteria to petroleum pollutants,this paper adopted the method of improving the strain surface hydrophobicity,and studied the change rules and regulatory measures of the surface hydrophobicity of three strains of petroleum degrading bacteria under different growth cycle,growth substrate,salinity and surfactant conditions,and obtained the best regulatory measures to improve the strain surface hydrophobicity.(2)In order to explore the change mechanism of strain surface hydrophobicity,the changes of outer membrane proteins,total membrane proteins,total proteins and lipopolysaccharide with the surface hydrophobicity of strain Y9,S2 and X1 were studied under different growth stages and different regulatory measures during the expanded culture process.The changes of protein composition were studied by SDS-PAGE of the isolated proteins.(3)After obtaining the method to improve the surface hydrophobicity of the strain,in order to explore its degradation effect on petroleum pollutants,the shaking bottle experiment was used to study the diesel degradation rate of each single strain and mixed bacteria after improving the surface hydrophobicity.The experimental results showed that,The oil degradation rate of the bacteria group constructed by the strain that improved the surface hydrophobicity was higher than that of the single strain group and the double strain group,and to improve the oil degradation rate of the surface hydrophobic bacteria group.(4)Through the indoor simulation of the oil-polluted environment in the East China Sea,the bioremediation experiment will be carried out by combining the mixed bacteria community that improves the surface hydrophobicity with the liophilic nutrient.Results show that due to the high surface hydrophobicity strains can be adhesive seawater surface oil,has a significant increase in surface waters of the bacteria and the experiment after 9 d,microbial surface waters from 3.20×10~5 CFU/m L rise to 5.68×1013 CFU/m L.At the same time,the lipophilic nutrient can provide nutrients required for microbial growth at the oil-water interface,thus accelerating the degradation of oil by petroleum degrading bacteria.The oil concentration of surface seawater decreases from 9267.5 mg/L to 175.8 mg/L,greatly improving the biodegradation effect.Therefore,the combination of surface hydrophobic strain and lipophilic nutrient in this paper can provide an effective foundation for the treatment of Marine environment in the actual situation.