Required for growth on alkanes. Probably involved in the uptake of micelle-solubilized alkanes. May facilitate the transfer of alkanes from the outer membrane to the inner membrane. Interacts with the outer membrane protein AupA. Expression increases during biofilm formation on n-hexadecane. Forms an operon with aupA. Mutants show a lower rate of biofilm formation on solid paraffin and on the liquid alkane n-hexadecane, while growth on nonalkane substrates was not affected. Planktonic growth on water-soluble substrates is not affected. Mutants are impaired in the assimilation of n-hexadecane solubilized in surfactant micelles.