Glucose, aerobic oxidation degradation

By combining the glycolytic pathway, the Krebs cycle, and oxidative phosphorylation, the energy yield from the aerobic degradation of glucose will be... 

The uptake of fructose occurs by active transport, while glucose, which can be utilized only by rare mutants, enters the cell by diffusion only. Fructose is degraded via the Entner-Doudoroff pathway and the products of this pathway are further oxidized via the usual routes of intermediary metabolism. The basic metabolism does not differ from that of other aerobic bacteria. The strains mentioned are even able to respire anaerobically with nitrate as a hydrogen acceptor they grow as denitrihers with fructose as the substrate. No anaerobic growth tms been observed under autotrophic conditions. 

Biodegradation can be either oxidative (aerobic) or reductive (anaerobic) depending on the environment the polymer is placed in. In the latter case, CH, and sometimes NH3 are formed as by-products of the degradation. Eor glucose, the biodegradation reaction can be summarized in the following reactions. 

Figure 14.24 NAD, as the coenzyme in glyceraldehyde-3-phosphate dehydrogenase (GAPDH), is used to oxidize glyceraldehyde-3-phosphate (GAP) to 1,3-bisphosphoglycerate during the degradation of glucose in glycolysis. One of the ways that NADH can be reoxidized to NAD is by the electron transport chain in mitochondria, where, under aerobic conditions, rearomatization of NADH helps to drive ATP synthesis.

Though the direct production of l-AA from D-glucose seems to be an ideal process, L-AA could be easily degraded in both water solutions [54] and ethanol solutions [55] under aerobic conditions. The aerobic culture processes for direct l-AA production have to face the oxidation of l-AA during the production processes. A possible process to avoid the oxidation of l-AA in water solution is to further convert it into its more stable derivatives, such as 2-O-D-glucopyranosyl-L-ascorbic acid (AA2G) [56]. 

Under aerobic conditions, glucose oxidation by the cortex produces very little lactic acid. Under anaerobic conditions glycolysis sets in, and lactic acid is produced with great rapidity. Brain cortex shows a typical Pasteur effect, in that the quantity of glucose degraded anaerobically is relatively greater than the quantity oxidised under aerobic conditions. 

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