Crude Oil Degrading Fingerprint and the Overexpression of Oxidase and Invasive Genes for n -hexadecane and Crude Oil Degradation in the Acinetobacter pittii H9-3 Strain

A crude oil-degrading bacterium named strain H9-3 was isolated from crude oil contaminated soil in the Northeastern area of China. Based on its morphological characteristics and 16S rDNA sequence analysis, strain H9-3 is affiliated to Acinetobacter pittii in the group of Gammaproteobacteria. The strain was efficient in removing 36.8% of the initial 10 g·L − 1 of crude oil within 21 days. GC-MS was performed and a preference was shown for n -C10, n -C11, i -C14, i -C17, i -C34, n -C12, n -C13, n -C14, n -C27, n -C32 and i -C13, over n -C16, n -C18–C22, n -C24– n -C31, and n -C36. This can be regarded as the specific fingerprint for crude oil degradation by strain H9-3 of Acinetobacter pittii . In addition to crude oil, it was shown that soybean oil and phenols can be utilized as carbon sources by strain H9-3. It was also shown that aniline and α -naphthol cannot be utilized for growth, but they can be tolerated by strain H9-3. Methylbenzene was neither utilized nor tolerated by strain H9-3. Although n -hexadecane was not preferentially consumed by strain H9-3, during culture with crude oil, it could be utilized for growth when it is the sole carbon source. The degradation of some branched alkanes ( i -C14, i -C17 and i -C34) and the preferential degradation of crude oil over phenols could be used as a reference for distinguishing A. pittii from A. calcoaceticus . The difference in gene expression was very significant and was induced by diverse carbon sources, as shown in the qRT-PCR results. The oxidation and adhesion events occurred at high frequency during alkane degration by Acinetobacter pittii strain H9-3 cells.