Studies on isolation, identification of crude oil degrading bacteria and its degradation capability

[Objective] To identify and characterize a crude oil degrading bacteria 2-9 isolated from a crude oil contaminated marine sponge from Dalian Bay,China.[Methods] According to the 16S rRNA genes sequences analysis,physiological and biochemical characterizations,DNA G+C content assaying,determination of cellular fatty acids and testing of carbon sources.Its capability of degrading crude oil was further determined.[Results] The strain 2-9 was identified as Nitratireductor basaltis.Cells are Gram-negative with catalase-positive and oxidase-positive.The similarity between its 16S rRNA gene and that of its most closely related type strain in GenBank Nitratireductor basaltis J3T was 99%.Growth of strain 2-9 occurred with 0 8%(W/V) NaCl(optimum 2%);strain 2-9 grew at 15 °C 42 °C(optimal 30 °C) and at pH 6.0 10.0(optimum pH 8.0).It metabolized many carbohydrates and organic acids;the G+C content of its genomic DNA was 57.29 mol%.The major fatty acids were C18:1ω7c(63.61%),C19:0 cycloω8c(16.97%),C18:0(4.28%) and C16:0(3.39%).When the initial concentration of crude oil was 1 g/L,the strain 2-9 could consume 63.5% of the crude oil in 14 days.[Conclusion] The strain 2-9 was a crude oil degrading bacteria,holding the potential of being applied in the bioremediation of oil spill.