1,3-Propanediol (1,3-PD) can be produced from glycerol by Klebsiella pneumoniae under micro-aerobic conditions. Recently, this fed-batch fermentation process has been successfully scaled up to 1 m(3). The final 1,3-PD concentration, molar yield and volumetric productivity of 72 g l(-1), 57% and 2.1 g l(-1 )h(-1), respectively, are close to those of 75 g l(-1), 61%, and 2.2 g l(-1 )h(-1) under anaerobic conditions. This process would be suitable for the production of 1,3-PD on a large scale.