Characterization of Anaerobic Petroleum Degrading Bacterium strain HD-1.

点击翻译按钮获取中文摘要

We isolated a new type of Gram-negative mixotrophic bacterium, Pseudomonas sp. HD-1, which is a facultative anaerobe. Cells were grown on CO_2 as a sole carbon source in the presence of H_2. Anaerobic growth of the strain was enhanced by the addition of aliphatic as well as aromatic hydrocarbons. When cells were grown on n-alkane anaerobically, many oil vacuoes formed in the cells and about 40-50% of the dry cell weight was lipid and oil. The total increase in the hydrophilic components of the cells indicated the anaerobic assimilation of aliphatic hydrocarbon. Electron microscopic observation showed that the cell surface was highly wavy and that the membrane had a multi-layr structure irrespective of the presence of oil.The strain was demonstrated to degrade tetradecane (C_<14>) under anaerobic condition and one of the major metabolic intermediates was identified as 1-dodecene (C_<12>). This result demonstrates that alkanes are biodegradable without molecular oxygen via a pathway different from beta-oxidation. The strain was found to grow on CO_2 in the presence of tetradecane and absence of H_2 gas and light. These facts strongly indicate that the bacterium is able to utilize alkane as an energy source anaerobically.