Before revision:  This tuning criterion discovered in our analysis is not satisfied by wild-type bacteria such as E. coli . Operating in the tuned regime leads to swim-speed enhancements in excess of 4 times relative to wild-type condition. This result provides a simple design rule to achieve optimal cargo transport for future bio-hybrid or synthetic flagellated micro-swimmers. Additionally, our study also reveals the existence of an anomalous propulsion regime where swim-speed increases with increasing load  .
After revision:  This tuning criterion discovered in our analysis is not satisfied by wild-type bacteria such as E. coli which swim 2-3 times slower than the maximum possible speed given the amount of available motor torque. Our analysis also reveals the existence of an anomalous propulsion regime where swim-speed increases with increasing load .