A Study On Isolation And Characterzation Of Oil Degrading Bacteria

While the industry development has been promoted by oil use, the crude oil pollution harms human being who pays a huge price for the environmental recovery. The bioremediation method in stead of the traditional physical and chemical methods is being used for the recovery of oil-contaminated soil and marine. At the present, the scientific research is focused on a stable, efficient, and economic oil-degrading bacteria strains. In fact, a complex of petroleum hydrocarbons may be degraded at a limited rate by a single bacteria strain. The key to bioremediation of the oil pollution is to build an complexity of several adaptable bacteria strainis that might degrade the crude oil at a high rate.In this study, the crude oil as a unique carbon source, two bacteria strains qs-1and qs-2were successfully isolated with enrichment cultures from long-term crude oil-contaminated soil in Daqing and intestine of marine fish. Identification in morphology, physiology and biochemistry, and molecular biology was conducted. The effects of carbon source, nitrogen source, temperature, pH value on the growth the two isolated strains were observed. The oil concentration, temperature, pH value, medium volume, inoculum volume, salinity, and additive was experimented respectively and optimized based on their effects on the growth of the two strains.The experimental results showed that strain qs-1and strain qs-2were identified as Pseudomonas sp. and Rhodococcus qingshengii respectively based on their morphologicl, physiological and biochemical features. The analysis of the16s rDNA gene sequence of strain qs-2by BLAST comparison showed that it was100%similarity to the Rhodococcus qingshengii （GenBank number NR₀43535）. Glucose as carbon source and NH4NO3as nitrogen source were suitable to growth of strain qs-1and qs-2at30℃and pH7.0. A49.3%degradation rate of the mixed strains might be gained in the ideal conditions that MgSO47H2O, CaCl2, KH2PO4, K2HPO4, NH4NO3, FeCl3, petroleum, pH, fermentation volume, inoculum volume, salinity, and temperature were0.02%,0.002%,0.1%,0.1%,0.1%,0.005%,2%and7.0,60mL/250mL,12%,2%,30℃respectively in9days.