Glycerol as carbon source

In addition to providing amino acids and glycerol as carbon sources, glucocorticoids promote gluconeogenesis by inducing synthesis of the enzyme phosphoenolpyruvate carboxykinase (PEPCK). 

Bretz, K. (2015) Succinic acid production in fed-batch fermentation of AnaerobiospirUlum succiniciproducens using glycerol as carbon source. Chem. Eng. Technol, 38, 1659-1664. 

Various bacteria own the ability to produce propionic acid within their metabolic pathways. Present-day research is focused on strains of Propionibacteriaceae and Clostridiaceae. Propionibacteria are using the dicarboxylic acid pathway (methylmalonyl coenzyme A-pathway) to produce the desired product. These gram-positive, anaerobic bacteria are able to use glucose, sucrose, lactate, lactose and glycerol as carbon source. The metabolic end products are propionate, succinate, carbon dioxide and acetate. Professionals acknowledge Propionibacterium... 

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. 

The crude glycerol phase from biodiesel production has several other potential applications. One use is to treat acid mine drainage. The crude glycerol served as carbon source for the sulfate-reducing bacteria in bioreactors used for this purpose (Za-mzow et al., 2006). Other applications include the utilization as a feed component for swine (Kijora Kupsch, 1996). 

C. necator H16 could utilize plant oil as carbon source after the hydrolysis of oil into fatty acids and glycerol by the secreted extracellular lipases and esterases. Initially, one pair of lipase/chaperone gene and one esterase gene were detected in Ralstonia sp. Ml by Quyen et al. (2005, 2007). However, recent gene expression study by Brigham et al. (2010) showed that C. necator H16 putatively possessed... 

Usually, glucose and sucrose are used as carbon sources for cellulose production, although other carbohydrates such as fructose, maltose, xylose, starch and glycerol have also been tried. The effect of initial glucose concentration on cellulose production is also important, since the formation of gluconic acid as a byproduct in the medium decreases the pH of the culture and ultimately decreases the production of cellulose. Cellulose yields at initial glucose concentrations of 6, 12, 24 and 48 g/L were studied, and the consumption of glucose was found to be 100, 100, 68 and 28 % of the initial concentration, respectively [14]. 

It was shown how industrial waste like surplus whey, crude glycerol phase, lignocellu-loses, molasses and residues from the slaughtering and biodiesel industry can be upgraded to substrates for biopolymer production. Applying such waste streams as carbon source can be regarded as the most promising route to make the entire PHA biopolymer production process economically competitive this is valid for bulk plastics made of petrochemical competitors as well as for special polymers currently used for niche products. 

The media for rifamycin SV productiem appear to have similar composition. In the original patent on rifamycin SV production by a mutant strain of Nocardia mediterranea (72), yields of about 2 g/liter are reported with a medium containing as carbon sources (g/liter) glucose, 95 glycerol, 40 and propyleneglycol, 5 and peanut meal, soybean meal, and ammonium ions as nitrogert sources. 

Gluconobacter can utilize sugar alcohols (mannitol, sorbitol, or glycerol) or hexoses (glucose or fructose) as carbon sources. Acids are formed from propanol, butanol, glycerol, erythritol, mannitol, arabinose, ribose, fructose, galactose, mannose, and maltose by a majority of strains (De Ley and Swings, 1984). 

Foster and Waksman (1938) supplied ethanol as the only carbon source and found that 70% was converted to fumaric acid. Using glucose, transient accumulation of ethanol is often observed, and apparently this might later be converted into fumaric acid. Glycerol, another potential side-product of fumaric acid fermentation, can also serve as carbon source for formation of fumaric acid (Moon et al. 2004). 

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