The present work is focused on precise temperature control of continuous bioreactor. The control of such process is difficult due to its highly nonlinear and dynamic nature. A Fractional Order PID (FOPID) controller is therefore designed for the purpose and Dragonfly Algorithm (DA) is used to evaluate the design parameters. DA is based on swarm intelligence (SI) having certain advantages whereas fractional order PID increases the degrees of freedom. The proposed controller may provide good control performance as it utilizes the advantages of both techniques. The Genetic Algorithm (GA) and Simulated Annealing (SA) are also used for optimization of the parameters. The performance of designed controllers is analyzed for set point tracking, and disturbance rejection. Results reveal that DA-FOPID outperforms the other designed controllers.