Xanthan gum is exo-polysaccharide, produced by Xanthomonas campestris. Considering a reactor operating in continuous mode, optimum dilution rate is determined by maximization condition. Optimum dilution rate is the dilution rate at which the productivity of xanthan gum is maximum. The current work is focused on implementing an algorithm for design of reactor, having optimum dilution rate as the operating condition. The steps of the algorithm and values obtained are briefed in this paper.