Isolation and degradation properties of heavy oil-degrading strain Bacillus flexus DL1-G

A bacterial strain DL1-G able to effectively degrade heavy oil was isolated from heavy oil-contaminated soil in the Dalian Bonded Area.The strain was identified to Bacillus flexus through morphological observation,physiological characteristics,16S rRNA gene sequence and phylogenetic tree analysis.The results showed that the degradation rate of 1g/L heavy oil was 39.89%,the total absolute contents of saturated and aromatic hydrocarbons was decreased by 68.30%.The saturated hydrocarbon nC11～nC38,nC6～nC30-alkyl cyclohexanes,pristine,phytane were undetected by gas chromatography-mass spectrometry(GC-MS) after biotreatment,more than 99% C14～C16-bicyclic sesquiterpanes,8α(H),8β(H)-Drimane degraded,13β(H),14α(H)-C19～C29-tricyclic terpanes and 11 kinds of steroidal compounds degraded by 36.32% and 12.04%,respectively.Among the aromatic hydrocarobons,more than 90% naphthalene series,fluorene series,dibenzothiophene series were degraded,anthracene,phenanthrene,fluorine,pyrene and naphthalene were degraded by 98.55%、97.16%、82.98 %、64.85%、63.61%,respectively,indicating strain DL1-G might play a significant role in biotreatment of heavy oil pollution.