Bacterial accumulation in a throttled flow

ERNESTO ALTSHULER; ADOLFO J. BANCHIO; ANKE LINDNER; VERONICA I. MARCONI; GASTON L. MIÑO; ARAMIS RIVERA; ERIC CLÉMENT

Rotterdam

Conferencia; 9th International Conference on Porous Media and Annual Meeting; 2017

interpore

In confined environments, such as narrow passages or porous media, bacteria suspensions can undergo significant modification of their transport properties. Under these conditions, both accumulations caused by ratchet arrangement, and attachment to surfaces leading to biofilm formation can be observed. In addition, the combination of flow and surface shape can have significant impacts on the microorganisms? behavior that allow processes such as rheotaxis to occur. Under these conditions, the transport of the bacterial suspension differs significantly from passive suspensions. Here we systematically test this scenario on Escherichia coli suspensions flowing in a straight channel with a funnel‐like constriction in the middle[1]. This constriction is characterized by the aperture (Wf) and its angle (Θf). We explore how the modification of Wf and Θf affects the accumulation of bacteria in the channel. Concentrations of bacteria passing the constriction were observed for all the cases. However, the range of flow rates producing such accumulation varied with the geometry. We are able to partially reproduce the experimental results using a simple phenomenological model containing the different forces experienced by E. coli in a confined  geometry.