Glucose substrates

The ethanol selling price is very sensitive to the glucose substrate... 

Figure 15. Relation of ethanol selling price to glucose substrate costs...

Figure 26.4A shows the calibration curve for GOX-B-immunosen-sors as a function of anti-CT concentrations. It has to be noted that very fast response times of the glucose substrate (3—6s) are observed highlighting the good diffusion of H202 to the underlying platinum surface. 

Glucose Substrate Dissolve 539 g of anhydrous glucose and 1.0 g of magnesium sulfate (MgS04-7H20) in 700 mL of water or the manufacturer s recommended buffer, previously heated to 50° to 60°. Cool the solution to room temperature, and adjust the pH as specified by the enzyme manufacturer. Transfer the solution to a 1000-mL volumetric flask, dilute to volume with water or the specified buffer, and mix. Transfer to a vacuum flask, and de-aerate for 30 min. 

Sample Preparation Transfer to a 500-mL vacuum flask an amount of the sample, accurately weighed in grams or measured in milliliters, as appropriate, sufficient to obtain 2000 to 8000 glucose isomerase units (GIC1J). Add 200 mL of Glucose Substrate, stir gently for 15 s, and repeat the stirring every 5 min for 40 min. De-aerate by vacuum for 30 min. 

Assay Adjust the flow of the Glucose Substrate to such a rate that a fractional conversion of 0.2 to 0.3 will be produced, based on the estimated activity of the sample. Calculate the fractional conversion from optical rotation values obtained on the starting Glucose Substrate and the sample effluent, as specified under Calculations, below. After establishing the correct flow rate, run the column overnight (16 h minimum), then check the pH of the Glucose Substrate, and readjust if necessary to the specified pH. Measure the flow rate, and collect a sample of the column effluent. Cover the effluent sample, allow it to stand for 30 min at room temperature, and then determine the fractional conversion of glucose to fructose (see Calculations, below). If the conversion is less than 0.2... 

Specific Rotation Measure the optical rotation of the effluent sample and of the starting Glucose Substrate at 25.0°, and calculate their specific rotations [see Optical (Specific) Rotation, Appendix IIB] by the equation... 

Using Rhodosprillum rubrum KS 301 strain, continuous photo-biological hydrogen production was tried using a 1.5 1 Nossle loop type photo-bioreactor. With glucose substrate, a hydrogen production velocity of 91 ml-h 1 was obtained under 12 klux irradiation. 

Non-enzymic aldose-ketose isomerisations that are acid catalysed appear to involve a 1,2-hydride shift. During acid-catalysed rearrangement of glucose to fructose, the label of [2- H]glucose substrate is retained in the [l- H]fructose product, distributed equally between the proR and proS positions." In the reverse sense retention of the label of tritiated fructose in the glucose and mannose products was not complete. Similar observations were made for the xylose-xylulose interconversion." With an appropriate sugar configuration (ribose), even the base-catalysed reaction proceeds partly with retention of label, presumably by the same mechanism as with trioses. 

Addition of laminarabiose to the incubation mixture increases the incorporation of D-glucosyl group from the UDP-D-glucose substrate into paramylon by about 20 to 30%. There is no indication that the laminarabiose serves as an acceptor that is incorporated into the polysaccharide. 

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