Shaking alone, without concurrent aeration, affects the growth characteristics of Escherichia coli
Aims: This study investigated the effects of linear vibration on cultures grown
in both hard- and soft-sided containers to determine whether vibration alone
affected the growth rate.
Methods and Results: Cultures of Escherichia coli were exposed to vibrational
acceleration with and without access to additional oxygen. Vibrated cultures
grown in hard-sided containers exited lag phase earlier and had a higher final
yield than identical unshaken cultures, whether or not the cultures had access
to ambient air. Cultures grown in soft-sided containers showed no response to
Conclusions: Vibration in hard-sided containers decreases the length of the lag
phase and increases final OD in E. coli, with or without increased oxygenation.
Increased mixing and improved suspension, which result from vibration of cul-
tures in hard-sided containers, are the most likely physical mechanisms for the
more favorable culture conditions.
Significance and Impact of the Study: This paper demonstrates that growth
enhancement of shaken cultures is a function of the rigidity of the vessel even
without aeration of the medium.