Sucrose, purification

The ion-exclusion process for sucrose purification has been practiced commercially by Firm Sugar (104). This process operates in a cycHc-batch mode and provides a sucrose product that does not contain the highly molassogenic salt impurities and thus can be recycled to the crystallizers for additional sucrose recovery. 

Ordinary glucose is ct-glucopyranose monohydrate m.p. 80-85°C and [ajp 4-113-4 . In solution it gives a mixture with the form with [alo 4-52-5 . It is manufactured from starch by hydrolysis with mineral acids, purification and crystallization, and is widely used in the confectionery and other food industries. It is about 70% as sweet as sucrose. 

J. C. P. Chen and C.-C. Chou, eds.. Cane Sugar Handbook, John Wiley Sons, Inc., New York, 1993 comprehensive reference with emphasis on sucrose extraction and purification. 

Chlorophyll b [519-62-0] M 907.52, sinters at 86-92 , sinters at 170 , dec at 160-170 , m 183-185 , 190-195 , [alj, -267 (Me2CO + McOH), [a] j-133 (McOH + Pyridine 95 5). See purification of chlorophyll a, and is separated from "a" by chromatography on sucrose [UV, IR Stoll and Weidemann Helv Chim Acta 42 679, 681 7959]. It forms red-black hexagonal bipyramids or four sided plates from dilute EtOH and has been recrystd from CHCl3-MeOH. It is soluble in MeOH, EtOH, EtOAc and insoluble in pet ether. [J Am Chem Soc 88 5037 1966.]... 

The purification is done by sucrose density-gradient centrifugation (DeSa and Hastings, 1968 Hastings and Dunlap, 1986). Six sucrose... 

Because plants present chlorophylls and carotenoids simultaneously, it may be useful to separate both groups from each other in a laboratory or preparative scale in order to avoid contamination in further purification steps, mainly when they are prepared in large amounts. Clean-up procedures using an open column packed with absorbents such as alumina, magnesia, polyethylene powder, powdered sucrose, DEAE-Sepharose, starch, cellulose, or MgO HyfloSupercel are good approaches. MgO HyfloSupercel in a proportion of 1 1 or 1 2 is the usual adsorbent. Sucrose and cellulose are interesting as they do not alter the chlorophylls, but they are tedious to work with. 

The amount of mix to add depends on the experimental setting and the number of fractions collected. We typically add 70 pi of spike-in mix into an entire sucrose gradient, where each fraction receives the relative share from that amount. For example, 35 pi of the spike-in mix will be added to each fraction of a gradient that was divided into two, and 7 pi of this mix will be added to each fraction of a gradient that was divided into 10fractions. The added amounts should consider losses during purification steps and that a minimum of 0.2 ng of each spike is needed to yield sufficient signal in the microarray hybridization. 

S. Ravaud, H. Watzlawick, R. Haser, R. Mattes, and N. Aghajari, Overexpression, purification, crystallization and preliminary diffraction studies of the Protaminobacter rubrum sucrose isomerase SmuA, Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun., 62 (2006) 74-76. 

Enbrel is a product now approved for medical use that is based upon this strategy. The product is an engineered hybrid protein consisting of the extracellular domain of the TNF p75 receptor fused directly to the Fc (constant) region of human IgG (see Box 13.2 for a discussion of antibody structure) The product is expressed in a CHO cell line from which it is excreted as a dimeric soluble protein of approximately 150 kDa. After purification and excipient addition (mannitol, sucrose and trometamol), the product is freeze-dried. It is indicated for the treatment of rheumatoid arthritis and is usually administered as a twice-weekly s.c. injection of 25 mg product reconstituted in WFI. Enbrel functions as a competitive inhibitor of TNF, a major pro-inflammatory cytokine. Binding of TNF to Enbrel prevents it from binding to its true cell surface receptors. The antibody Fc component of the hybrid protein confers an extended serum half-life on the product, increasing it by fivefold relative to the soluble TNF receptor portion alone. 

In a study of the pectinesterase from bananas,64,85,102 three pectinesterase fractions were obtained after respective extraction with water, 150 mM sodium chloride, and 150 mM sodium chloride of pH 7.5. The fractions obtained were further purified by fractional salting-out with ammonium sulfate, and chromatography on columns of DEAE- and CM-cellulose. A 50-fold purification was achieved, and the individual, purified fractions were characterized with respect to different effects of cations, inhibition by sucrose, and reaction kinetics. 

Solubilization and Partial Purification of Cytochrome P-450 from Hepatic Microsomes of Male, DBA-Pretreated Little Skates. Washed hepatic microsomes (3) from the livers of 10 skates were suspended in 0.25 M sucrose and frozen under nitrogen (-5 to -10°) at the Maine laboratory. They were then packed in dry ice and transported to NIEHS, Research Triangle Park, NC, within 14 days of preparation and were stored at -62°C until use. Microsomes... 

H2A.Bbd was discovered as an H2A-like protein encoded by human ESTs [77]. H2A.Bbd is only 42% identical to conventional H2A and is smaller due to a shortened C-terminus that lacks the ubiquitination site that is present in most other H2As (Fig. 6). H2A.Bbd appears to be associated with nucleosomes as indicated by the co-purification of an epitope-tagged H2A.Bbd with nucleosomal fragments in a sucrose gradient run at high ionic strength [77]. 

Ciystallization from solution is an important separation and purification process in a wide variety of industries. These range from basic materials such as sucrose, sodium chloride and fertilizer chemicals to pharmaceuticals, catalysts and specialty chemicals. The major purpose of crystallization processes is the production of a pure product. In practice however, a number of additional product specifications are often made. They may include such properties as the ciystd size distribution (or average size), bulk density, filterability, slurry viscosity, and dry solids flow properties. These properties depend on the crystal size distribution and crystal shape. The goal of crystallization research therefore, is to develop theories and techniques to allow control of purity, size distribution and shape of crystals. 

In the large-scale production of PHAs, the extraction and purification of PHA from biomass is a crucial factor for determining the practical importance of these polymers. It is important that PHAs can be extracted efficiently and easily, much like the extraction of endogenous compounds such as starch, sucrose, and oil. 

Figure 6. Partial purification of Inhibitors I and II mRNA. Fractions containing Inhibitors I and II mRNA determined by in vitro translation analyses were recovered from an initial 15-30% linear sucrose gradient, precipitated by cold ethanol, and applied to a 10-25% linear sucrose gradient. The sample was centrifuged for 36 h at 25,000 rpm. Fractions of the gradient were collected and subjected to in vitro translation analyses. The upper graph represents total methionine incorporation assayed with 1 jiL of the translation mixture as described (ll). The bottom figure quantitates the radiolabel incorporated specifically into Inhibitor I (solid bars) and Inhibitor II (open bars).

In the initial stages of purification, sucrose is recovered in juice form by crushing cane stalks or by extraction of sliced sugarbeets (cossettes) with hot water. The resulting solutions are clarified with lime, then evaporated to thick syrups from which sugar is recovered by crystallization. The final syrup obtained after exhaustive crystallization of sucrose is known as molasses. Enhanced recovery of sucrose from beet molasses is accomplished by ion-exclusion chromatography, a process used in some sugar mills in the United States, Japan, Finland, and Austria. 

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