Previously, organisms incapable of producing 1,3-propanediol (1,3-PDO), were thought to be incapable of fermenting glycerol. Now Ramon Gonzalez of Rice University, Houston, Tex., et al. show that this is not so, as Paenibacillus macerans, which cannot produce 1,3-PDO, can nonetheless ferment glycerol, producing large quantities of ethanol. That is useful, because as a byproduct of biodiesel and bioethanol production, glycerol is plentiful and inexpensive. This is the first demonstration of this phenomenon in a gram-positive organism; previously, this group found it to occur in Escherichia coli, a gram-negative species. "We will continue to investigate the fermentative metabolism of glycerol in these organisms, and to this end we are using systems biology techniques-gene arrays, proteomics, and metabolic flux analysis," says Gonzalez.
(A. Gupta, A. Murarka, P. Campbell, and R. Gonzalez, 2009. Anaerobic fermentation of glycerol in Paenibacillus macerans: metabolic pathways and environmental determinants. Appl. Environ. Microbiol. 75:5871-5883.)