The Change On Arthrobacter Simplex Cell Properties Under Ethanol Condition And Its Influence On Material Transportation Across Cell Barrier

In this study, ethanol tolerance strain Arthrobacter simplex TCCC 11037 UV15X1-2 obtained in our previous work was selected as a model, adaptive behavior of bacteria was studied in the presence of ethanol under growth system, change of cell properties and its influence on material transportation across cell barrier were analysed pretreatment with ethanol under resting system. Our results would be offer a wide range basic data for the Arthrobacter simplex organic solvent adaptation mechanism, and laid a foundation for the relationship between cell properties and material transportation across cell barrier or catalytic reaction efficiency.Arthrobacter simplex TCCC 11037 UV15X1-2 was cultured with the process of different concentration ethanol in mid-exponential phase, growth curve and survival of bacteria was determined. Favourable growth property were observed when ethanol concentration no more than 6%, while the growth rate and the maximum biomass decreased obviously, and the survival rate almost 0 when ethanol ranged from 8% to 15%, it indicated that high ethanol concentration cause severe toxic to bacteria cells; Cell cultured with different concentration of ethanol for 3h, various cell properties were researched with the change of ethanol concentration. The results showed that the descend of metabolism acitivity and energy level and the increase of ROS accumulation is the important cause of bacteria growth suppress and even the death under high ethanol condition; Cis-trans isomerization of unsaturated fatty acids was an important adaption behavior of cells under ethanol condition; Significant differently expressed proteins of Arthrobacter simplex TCCC 11037 UV15X1-2 cell in the presence of 6% ethanol under growth system were identified by LC-MS/MS and bioinformatics methods, the results showed that some proteins may be associated with ethanol tolerance, such as:chaperone protein GroEL, DnaJ, DnaK, C1pB, DNA homologous recombination repair protein RecA、UvrD/REP helicase, oxidative stress protein glyoxalase.Conversion reaction and various cell properties of resting cells were analysed after pretreatment with different concentration of ethanol. The results showed that the initial conversion rate of cortisone acetate increased by 32.6% when cell was pretreatment with 8% ethanol for 1h, the analysis of cell properties indicaed that increased cell permeability is the main reason for the increase of initial conversion rate. The analysis of cell lipid and fatty acid composition indicaed that increased cell permeability after the ethanol pretreatment was associated with the destruction of membrane lipid permutation order, such as, cell total lipid content was decreased, total unsaturated fatty acids content was increased and the cis unsaturated fatty acid content was increased. Significant differently expressed proteins of Arthrobacter simplex TCCC 11037 UV15X1-2 cell pretreatment with 8% ethanol under resting system was identified by LC-MS/MS and bioinformatics methods, the results showed that glucosamine/fructose-6-phosphate aminotransferase, putative UDP-N-acetyl muramyl tripeptide synthetase, LysM and putative M23 family peptidase related to cell wall peptidoglycan synthesis,3-ketoacyl-ACP reductase, putative acetyl/ propionyl CoA carboxylase,3-oxoacyl-(ACP) synthase Ⅱ related to cell fatty acid synthesis, may associated with the increasing of cell permeability after pretreatment with ethanol.