Sphere-like bacterial cellulose(BC) is produced in agitated culture,and shows great potentials as an industrial material due to its unique properties.In this study,potato starch of different concentrations was added to Hestrin-Schramm medium and the effects of potato starch on the yield,shape uniformity,and structure of sphere-like BC produced by K.nataicola Y19 in agitated culture were investigated.When 0.15% potato starch was added,3.660 g /L BC was obtained as compared with 2.328 g /L BC produced from the control.And the uniformity of the sphere-like BC was better.By scanning electron microscopy,BC formed through addition of 0.15% potato starch was looser and showed more gaps and holes in the network structure,and the width of its cellulose fiber was broader.By X-ray diffraction and Fourier transforms infrared spectroscopy,more cellulose Iβformed and the crystallinity and crystal size of the sphere-like BC were decreased through addition of potato starch.