Autonomous manipulation and assembly at micro/nanoscale continues to be one of the main challenges of micro/nanorobotics. Biomotors are increasingly being considered as robust, versatile and cost-effective choices for a variety of micro/nanorobotic tasks. Here we propose utilization of motility and chemotaxis in flagellated bacteria for autonomous sorting of 6 µm and 10 µm micro-particles within a microfluidic platform. Difference in surface chemistry of the 6 µm and 10 µm particles are exploited to selectively assemble bacteria onto 6 µm particles and separate them from 10 µm particles via chemotaxis motility of the attached bacteria. It has been shown that within 1 hour, an increasingly larger number of 6 µm particles accumulate within a 600 µm radius, near the chemo-attractant source.