Functional Analysis of Novel Genes Encoding Long-Chain -Alkane Hydroxylases in sp. Strain CH91.

sp. strain CH91 is capable of utilizing long-chain -alkanes as the sole carbon source. Two new genes ( and ) encoding AlkB-type alkane hydroxylase were predicted by its whole-genome sequence analysis. The purpose of this study was to elucidate the functional role of and genes in the -alkane degradation of strain CH91. RT-qPCR analyses revealed that the two genes were induced by -alkanes ranging from C16 to C36 and the expression of the gene was up-regulated much higher than that of . The knockout of the or gene in strain CH91 resulted in the obvious reduction of growth and degradation rates on C16-C36 -alkanes and the knockout mutant exhibited lower growth and degradation rate than the knockout mutant. When gene or was heterologously expressed in KOB2Δ1, the two genes could restore its alkane degradation activity. These results demonstrated that both and genes were responsible for C16-C36 -alkanes' degradation of strain CH91, and plays a more important role than . The functional characteristics of the two genes in the degradation of a broad range of -alkanes make them potential gene candidates for engineering the bacteria used for bioremediation of petroleum hydrocarbon contaminations.