Magnetotactic bacteria (MTB) can be controlled by an externally applied magnetic field. Their fast migration speed and quick response time, along with their capability to achieve 4 pN thrust force, make them well suited for micro-bio-actuators and bio-carriers. Here, we use conventional methods of microlithographyto construct a microfluidic device to evaluate the activity of MTB in microchannels. Experiments also prove that a single MC-1 MTB can push a 2 mum bead in a well controlled manner. Finally, we discuss the advantages of MTB based bio-carriers and prospect for future applications.