@article{ajmr2019734,
author={{Nasrin, Farhana and Azad, Dr. Abul Kalam and Hasan, Mohammad Rashedul and Kader, Dr. Md. Maruful and Rahman, Br. Gen. Md. Saidur and Hasan, Chowdhury Mohammad Monirul},
title={Adaptive Responses in the Metabolism of <i>Escherichia coli</i> in View of Gene Expressions under Aerobic and Micro-aerobic Condition},
journal={American Journal of Microbiological Research},
volume={7},
number={3},
pages={91--97},
year={2019},
url={http://pubs.sciepub.com/ajmr/7/3/4},
issn={2328-4137},
abstract={The major aims of biology to understanding life at a systems level. Escherichia coli is a metabolically versatile bacterium able to respond to changes in environmental factors availability. The effect of pH downshift on fermentation characteristics was investigated in a continuous culture of <i>Escherichia coli</i> at aerobic and micro-aerobic conditions.  Regardless of oxygen availability, higher levels of acetate were associated with lower biomass yields and lower glucose consumption rates at pH 5.5 as compared to the observations made at pH 7.0. Observed gene expressions indicated that the down- regulation of the glucose uptake rate corresponded to the down-regulation of<i> ptsG</i> gene expression which in turn was caused by the up-regulation of <i>mlc</i> gene under the positive control of Crp. In accordance with up-regulation of <i>arcA </i>gene expression at acidic conditions, the expressions of TCA cycle-related genes such as <i>icdA</i> and <i>gltA</i>,<i> </i>and the respiratory chain gene <i>cyoA </i>were down-regulated, whereas <i>cydB</i> gene expression was up-regulated. Decreased activity of the TCA cycle caused more acetate formation at lower pH levels. Under micro-aerobic condition, higher levels of formate and lactate were produced at lower pH due to up-regulation of <i>pflA, yfiD</i> and<i> ldhA </i>genes. Meanwhile, lower levels of ethanol were produced due to the down-regulation of <i>adhE</i> gene at lower pH, as compared to the observation at neutral pH. The combined effect of pH and temperature on gene expression was also investigated and observed that decreases in the specific glucose consumption rate were associated with increases in the specific acetate production rate. This type of information is useful for the production of recombinant proteins, bio-molecules, simultaneous saccharification and fermentation (SSF) and strain improvement.},
doi={10.12691/ajmr-7-3-4}
publisher={Science and Education Publishing}
}