@article{oai:tsukuba.repo.nii.ac.jp:00043405,
 author = {青柳, 秀紀 and Takahashi, Masato and Sawada, Yoshisuke and Aoyagi, Hideki},
 issue = {1},
 journal = {AMB Express},
 month = {Aug},
 note = {Monitoring the environmental factors during shake-flask culture of microorganisms can help to optimise the initial
steps of bioprocess development. Herein, we developed a circulation direct monitoring and sampling system
(CDMSS) that can monitor the behaviour of CO2
and O2
in the gas–liquid phases and obtain a sample without interrupting
the shaking of the culture in Erlenmeyer flasks capped with breathable culture plugs. Shake-flask culturing of
Escherichia coli using this set-up indicated that a high concentration of CO2
accumulated not only in the headspace
(maximum ~100 mg/L) but also in the culture broth (maximum ~85 mg/L) during the logarithmic phase (4.5–9.0 h).
By packing a CO2
absorbent in the gas circulation unit of CDMSS, a specialised shake-flask culture was developed to
remove CO2
from the headspace. It was posited that removing CO2
from the headspace would suppress increases
in the dissolved CO2
concentration in the culture broth (maximum ~15 mg/L). Furthermore, the logarithmic growth
phase (4.5–12.0 h) was extended, the U.O.D.580 and pH value increased, and acetic acid concentration was reduced,
compared with the control. To our knowledge, this is the first report of a method aimed at improving the growth of E.
coli cells without changing the composition of the medium, temperature, and shaking conditions.},
 title = {Development of a circulation direct sampling and monitoring system for O2 and CO2 concentrations in the gas–liquid phases of shake-flask systems during microbial cell culture},
 volume = {7},
 year = {2017}
}