Anaerobic metabolism fermentation, glycerol

Dharmadi, Y., Murarka, A. and Gonzalez, R. 2006. Anaerobic Fermentation of Glycerol by Escherichia Coli A New Platform for Metabolic Engineering. Biotechnol. Bioeng., 94, 821— 829. 

The fermentation of 1,3PD from glycerol (see Fig. 8.8c) was discovered in the late 19th century [60]. It has since been found that a considerable number of bacteria can use glycerol as a source of carbon and energy under anaerobic conditions and the reaction pathways have been elucidated [61]. Out of every three molecules of glycerol, one is oxidized, phosphorylated into DHAP and subsequently metabolized via the glycolysis pathway and the TCA cycle the other two are converted into 1,3PD, to maintain redox balance (see Fig. 8.9), via dehydration and NADH-driven reduction. 

Under aerobic conditions yeast may also use glycerol, ethanol and lactic acid which are themselves the products of anaerobic (fermentative) growth. Similarly the organic acids acetic, citric and malic are also metabolized by some species. Other compounds, generated by cellular metabolism, which appear in the medium and may be subsequently taken up by the cells, include pyruvic acid and acetaldehyde. In addition yeast cells may fix carbon dioxide to provide up to 5 % of their carbon requirement [4]. 

Dharmadi Y, Murarka A, Gonzalez R. (2006). Anaerobic fermentation of glycerol by Escherichia colt a new platform for metabolic engineering. Biotechnol Bioeng, 94(5), 821-829. 

Gonzalez, R., Murarka, A., Dharmadi, Y, et al., 2008. A new model for the anaerobic fermentation of glycerol in enteric bacteria trunk and auxiliary pathways in Escherichia coli. Metabolic Engineering 10,234-245. 

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