Title Trans-Membrane Transport of n-Octadecane by Pseudomonas sp. DG17
Author Fei Hua, Hong Qi Wang*, Yi Li, and Yi Cun Zhao
Address College of Water Sciences, Beijing Normal University, Beijing 100875, P. R. China
Bibliography Journal of Microbiology, 51(6),791–799, 2013,
DOI 10.1007/s12275-013-3259-6
Key Words Pseudomonas, n-octadecane transport, facilitate, energy-dependent, specific
Abstract The trans-membrane transport of hydrocarbons is an important and complex aspect of the process of biodegradation of hydrocarbons by microorganisms. The mechanism of transport of 14C n-octadecane by Pseudomonas sp. DG17, an alkane-degrading bacterium, was studied by the addition of ATP inhibitors and different substrate concentrations. When the concentration of n-octadecane was higher than 4.54 μmol/L, the transport of 14C n-octadecane was driven by a facilitated passive mechanism following the intra/extra substrate concentration gradient. However, when the cells were grown with a low concentration of the substrate, the cellular accumulation of n-octadecane, an energy-dependent process, was dramatically decreased by the presence of ATP inhibitors, and n-octadecane accumulation continually increased against its concentration gradient. Furthermore, the presence of non-labeled alkanes blocked 14C n-octadecane transport only in the induced cells, and the trans-membrane transport of n-octadecane was specific with an apparent dissociation constant Kt of 11.27 μmol/L and Vmax of 0.96 μmol/min/mg protein. The results indicated that the transmembrane transport of n-octadecane by Pseudomonas sp. DG17 was related to the substrate concentration and ATP.