The Effects Of Ethanol On Growth And Cell Morphology Of Arthorbacter Simplex

In this study, Arthrobacter simplex that was used in steroids1-en-dehydrogenation process was selected. Further more, the effects of organic solvent on cell morphology was systematily investigated.The ethanol tolerance mutant TCCC11037-UV15X1-2was obtained based on which the strains were screened by UV and high concentrations of ethanol domestication continuously, with growth activity and well hereditary stability in the presence of10%(v/v) concentrations. Both original strain and tolerance mutant could use the ethanol as sole carbon and energy source, especially for tolerance mutant. It also had growth activity even in the presence of6%(v/v) concentrations.When the ethanol was added to the culture medium system with the seeds, the growth of both strains were inhibited, and conspicuously for original strain. The results suggested that cell biomass and specific growth rate declined with the ethanol concentrations increased; When the ethanol was added at the logarithm growth later period of cells, the growth of original strain was inhibited significantly, and gradually increased with the ethanol concentrations increased. Compared with the original strain, the tolerance mutant with preferable ethanol tolerance, and the ethanol concentration range of4%promoted the growth of tolerance mutant.The ratio between cell surface and volume of original strain was decreased with the ethanol concentrations increased, and with significant dose-dependent of ethanol. The results also suggested that when it cells were replaced on environment without pressure, the cell surface areas were similar to those of cells at exponential phase without ethanol. This reduction of the relative surface represented an adaptive response to reduce the contact areas with the presence of ethanol, and it was induced by ethanol; For the tolerance mutant, the surface areas was not changed significantly with the concentration change and removal, it represented a relatively stable, long-term change. The cell morphology was researched with ethanol was added to the resting cells system. The results showed that the response of the cell morpholory was completed in a relatively short period of time, and the changes of cell morphology were not signifyeant dose-dependent of ethanol.