Considering the time-delay in fermentation process, we propose a nonlinear time-delay system to describe the fed-batch process of glycerol bioconversion to 1,3-propanediol(1,3-PD). Taking the 1,3-PD yield of per unit time at the terminal time as the performance index, regarding the feeding rates of glycerol and 1,3-PD as well as the terminal time as the control variables, we present a time-delay optimal control problem subject to control and state constraints. To solve this optimal control problem, by using time-scaling transformation, we first transform it into an equivalent one with fixed terminal time. Then, the equivalent problem is approximated by a sequence of finite-dimensional optimization problems using the control parameterization method. Finally, an improved particle swarm optimization method is constructed to solve the approximate optimization problem. Numerical results show that 1,3-PD yield of per unit time at the terminal time increases 58% compared with the previous result.