Expression of Alkane Hydroxylase from Acinetobacter sp. Strain ADP1 Is Induced by a Broad Range of n-Alkanes and Requires the Transcriptional Activator AlkR

In Acinetobacter sp. strain ADP1, alkane degradation depends on at least five essential genes. rubAB and xcpR are constitutively transcribed. Here we describe inducible transcription of alkM, which strictly depends on the presence of the transcriptional activator AlkR. alkR itself is expressed at a low level, while a chromosomally located alkM::lacZ fusion is inducible by middle-chain-length alkanes from heptane to undecane, which do not support growth of ADP1, and by long-chain-length alkanes from dodecane to octadecane, which are used as sources of carbon and energy. The putative AlkM substrate 1-dodecene is also an effective inducer. Products of alkane hydroxylase activity like 1-dodecanol prevent induction of alkM expression. alkM is expressed only in stationary phase, suggesting its dependence on at least one other regulatory mechanism.