Study On The Isolation, Screening And Identification Of Lubricating Oil-Degrading Strains And Their Degradation Capability

Three lubrication oil degradation bacteria strains were isolated from Fuzhou Xiangban and Xiamen sewage treatment plants. Through the identification of the morphology and physiology, the result showed that strain FZ5 was Alcaligenesfaecalis, X2 was Comamonas acidovorans, 2-2 was Ochrobactrum anthropi. Strain FZ5 had the highest degradation efficiency of lubrication oil.Through studing on the optimal liquid nutrient medium and differential culturing conditions, the results showed that the dry biomasses of strain FZ5 was about 2.0g/L. After some trace elements (MgSO₄·7H₂O 5.0mg/L, CuSO₄·5H₂O 4.0mg/L, MnSO₄·H₂O 4.0mg/L, FeSO₄·7H₂O 1.0mg/L, CaCl₂·2H₂O 4.0mg/L)were added to the lubrication oil degradation culture media and the degradation rate of lubrication oil reaching 53.3%, under conditions: 30℃, 400mg/L lubrication oil concentration, initial pH 7.0, 190r/min, inoculated volume 4mL, culture volumes 60mL, NaCl 0.9%, and cultivation 2d. The strain FZ5 was immobilized by magnetic suspension minor balls, which were prepared using sodium alginate, polyvinyl alcohol, and magnetic MnFe₂O₄-carbon as complex supports.The results showed that degradation rate of lubrication oil by immobilization strain FZ5 reached 91.21%. In the experiment, we found that promoting interaction of lubrication oil degradation existed between the strains X2 and FZ5, and competitive inhibition to the strains X2 and FZ5 caused by the strain 2-2. By studying the mechanism of the strain FZ5, it was found that the extracellular enzyme has played an important role during the process of degradation. Some sugar surfactants were produced during the degradation of lubrication oil. It was supposed that strain FZ5 uptake modes of lubrication oil maybe combine contact behavior of interface with mediated effect of surfactants.