Substrate solution glucose, fructose

Glutaraldehyde Substrate solution (glucose, fructose, protein)... 

A volume of 450 ml of cubes treated by the method described in (A) were reacted in a 1.5 liter fluidized bed fermenter with a substrate solution comprised of 100 g/L glucose, 100 g/L fructose and a protein concentration of 6.1 g/L, at a D of 0.053 Iv1, and titrated with 3 N KOH. After 48 hours, 68.8% of the substrate was converted with a resulting production of 3.65 g sorbitol/L h and 0.6 g sorbitol/g protein h. After approximately 50 days, the productivity of the fermenter was reduced by about one half. 

Harrison, Tarr and Hibbert96 investigated the production of levan from sucrose by the action of Bacillus subtilis Cohn and B. mesentericus Trevisan. Nutrient solutions containing 10% carbohydrate, 0.1% peptone, 0.2% disodium hydrogen phosphate and 0.5% potassium chloride were incubated at 37° for six days. Levan formation occurred only with sucrose and raffinose, and not with melezitose, lactose, maltose, D-xylose, D-glucose or D-fructose. It was therefore suggested that only those carbohydrates with a terminal D-fructofuranose residue were satisfactory substrates for levan formation. 

This enzyme [EC 2.4.1.7], also known as sucrose gluco-syltransferase, catalyzes the reaction of sucrose with orthophosphate to produce D-fructose and a-D-glucose 1-phosphate. In the forward reaction, arsenate may replace phosphate as the substrate. However, the resulting product is unstable in aqueous solutions. In the reverse reaction, various ketoses and L-arabinose may replace D-fructose. See Arsenolysis... 

Mannitol has often been used as an osmotic regulator in the external solutions, and has been presumed to be inert. It was found to be a respiratory substrate in 15 of 26 species representing 17 families of higher plants, some of which were capable of utilization of mannitol that was equal to that of n-glucose and D-fructose. Oat (Avena sativa), most often used for the cell-wall studies, showed only a slight output of carbon dioxide from labeled mannitol. About 10% of the carbon in the mannitol was converted, with time, into the hemicellulose and cellulose fractions. Only the glucose, and, perhaps, the cellobiose, was labeled.4 ... 

The ring structure is the predominant form of the substrates glucose and fructose in solution. Ring opening of a sugar substrate prior to isomerization catalyzed by the other PGIs discussed above is assisted by a His side chain. The structure of a bound substrate... 

Stereospecificity. Sucrose, a major product of photosynthesis in green leaves, is synthesized by a battery of enzymes. The substrates for sucrose synthesis, d-glucose and d-fructose, are a mixture of a and P anomers as well as acyclic compounds in solution. Nonetheless, sucrose consists of a-d-glucose linked by its carbon-1 atom to the carbon-2 atom of P-d-fructose. How can the specificity of sucrose be explained in light of the potential substrates ... 

The production of biodegradable polymeric materials by biotechnological processing is a traditional nonfood use of sucrose, leading to some - homo-polysaccharides -+dextrans, formed by the action of cell-independent dextran sucrose from Leuco-nostoc mesenteroides on sucrose solutions or - molasses. The glucose moiety is used as the substrate donor, whereas the fructose remains unreacted - fructans, formed by cell-immobilized enzymes from Bacillus polymyxa on sucrose solutions or molasses. The fructose moiety is used for building the polymeric chain, whereas the equivalent glucose and sucrose remain unreacted. 

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