Kinetics of cell growth and crystalline nanocellulose production by Komagataeibacter xylinus

The mass transfer rate of oxygen often limits the cell growth of aerobic bacteria and its product formation. Baffles and agitation increase mixing and oxygen transfer. The effects of agitation rates on the cell growth and oxygen uptake rate (OUR) of Gluconacetobacter xylinus (G. xylinus), recently named Komagataeibacter xylinus (K. xylinus), in stirred-tank bioreactors are presented in this study. Agitation rates also affected the bacterial cellulose production with yields of 1.13 and 0.54 g/l at agitation rates of 700 rpm and 500 rpm, respectively. Stirred-tank bioreactors offer a means to scale up production and result in higher production yields of bacterial cellulose. Separation and purification of bacterial cellulose was achieved in a one step process and preserved the crystalline cellulose Iα structure. This work gives insight into the conditions necessary to increase bacterial cellulose production and to alter the bacterial cellulose crystallinity during bioprocessing.