Wa. Duetz et B. Witholt, Effectiveness of orbital shaking for the aeration of suspended bacterial cultures in square-deepwell microtiter plates, BIOCH ENG J, 7(2), 2001, pp. 113-115
Growth of heterogeneous culture collections in microtiter plates is advanta
geous for logistic reasons and also in enabling significant savings in medi
um costs, labor input and use of equipment during large screening projects.
The main hurdles to overcome for aerobic microbial strains are the prevent
ion of cross-contamination and excessive evaporation while assuring suffici
ent aeration rates. For this purpose we developed a sandwich spongy silicon
e/cotton wool cover to close the wells of square-deepwell microtiter plates
. Oxygen transfer rates were derived from growth curves of Pseudomonas puti
da and were shown to be threefold higher during orbital shaking at a shakin
g diameter of 5 cm at 300 rpm (24 mmol O-2 l(-1) h(-1) at a culture volume
of 0.75 ml) in comparison to a shaking diameter of 2.5 cm. Photographic ana
lysis showed a clear influence of the shaking diameter on the hydrodynamic
behavior in the wells; during shaking at a 2.5 cm amplitude, out-of-phase c
onditions occurred resulting in poor vertical mixing, while a 5 cm shaking
amplitude led to an optimal surface to volume ratio and a turbulent flow. (
C) 2001 Elsevier Science B.V. All rights reserved.