  The viscosity of an active suspension of E-Coli bacteria is determined
experimentally in the dilute and semi dilute regime using a Y shaped
micro-fluidic channel. From the position of the interface between the pure
suspending fluid and the suspension, we identify rheo-thickening and
rheo-thinning regimes as well as situations at low shear rate where the
viscosity of the bacteria suspension can be lower than the viscosity of the
suspending fluid. In addition, bacteria concentration and velocity profiles in
the bulk are directly measured in the micro-channel.
