for many years, 1,3-PD production has relied primarily on two genera of microorganism : Clostridium spp. and Klebsiella spp. , along with genetically engineered Escherichia coli, which is operating in an industrial process. Several recent papers have demonstrated that Citrobacter species are worth considering as 1,3-PD producers. In particular, an out standing result obtained using the Citrobacter freundii FMCC-B 294 (vk-19) strain (66 g/L of 1,3-PD at high yield and productivity from raw glycerol and under non-sterlie conditions, places this species among the major players in microbial 1,3-PD production.