Pullulans

Pullulans.—Conditions for the complete benzylation of pullulan with benzyl chloride in DMSO-sodium hydride in a single step have been reported.  

Starches.—Conditions have been reported for the complete hydrolysis of starch with acid so that no significant acid-catalysed reversion occurred.  

Periodate-oxidized starch has been incorporated into poly(vinyl alcohol) membranes the properties, including the permeability, of the membranes were studied.  

A Blue Starch-agar plate, Phadebas Blue starch, - and Remazol Brilliant Blue starch have been used in the detection of amylase activity. 

A report on the preparation of 2-hydroxyethylated D-glucoses is of relevance to the preparation of the corresponding starch derivatives.  

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Pullularia pullulans Bhi ctonia solani Bhi pus arrhi s B. nigricans Bosellinia sp. 

Nonionic hydrophilic Polyethylene glycol Soluble starch, methyl cellulose, pullulan Dextran Above samples plus hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide Distilled water 0.01 N NaOH DMSO Buffer or salt solution (e.g., 0.1— 0.5 M NaNO,)... 

Corn Starch Dextrans Gelatin Lignins Pullulans Potato Starch Polysaccharides Wheat Starch... 

Figure 6.21 shows the calibration curves of the SB-800 HQ series using standard pullulan. Because a high molecular weight standard sample is not available, the calibration curves of 805 and 806 are partly estimates (dotted lines). The difference in the conformation between polyethylene oxide (PEO) and pullulan in the solvent causes a shift of the calibration curves of pullulan slightly higher than those of PEO. The OHpak SB-800HQ series is better suited for the analysis of hydrophilic samples than the Asahipak GS/GE series. 

Deionized water can be used as an eluent for the analysis of nonionic polymers such as pullulan and polyethylene glycol. However, in most cases, salt solutions or buffer solutions are used to decrease ionic or other interactions between samples and the stationary phase or to prevent sample association (Eigs. 6.22 and 6.23, pages 196 and 197). 

Coiumn type Column size (mm) Theoretical plate number Flow rate (ml/min) Exclusion limit Pullulan Usable pH range Particle size (ftm) Maximum pressure (kgf/cm ) Maximum temperature (°C)... 

FIGURE 6.40 Calibration curves of Shodex PROTEiN KW-800 series. Column Shodex PROTEiN KW-802.S, KW-803, KW-804, 8.0 mm i.d. X 300 mm. Eiuent Pullulan, PEG PEO Purified water, Protein SO mM Sodium phosphate buffer + 0.3 M NaCI (pH 7.0). Flow rate 1.0 mL/min. Detector Pullulan. PEG PEO Shodex Rl Protein Shodex UV (220 nm). Column temp. Ambient. 

Nonionic Polyethylene oxide Polyethylene glycol Polysaccharides Pullulans Dextrans Cellulosics Polyvinyl alcohol Polyacrylamide 0.1 M NaNOj... 

The GBR resin works well for nonionic and certain ionic polymers such as various native and derivatized starches, including sodium carboxymethylcel-lulose, methylcellulose, dextrans, carrageenans, hydroxypropyl methylcellu-lose, cellulose sulfate, and pullulans. GBR columns can be used in virtually any solvent or mixture of solvents from hexane to 1 M NaOH as long as they are miscible. Using sulfonated PDVB gels, mixtures of methanol and 0.1 M Na acetate will run many polar ionic-type polymers such as poly-2-acrylamido-2-methyl-l-propanesulfonic acid, polystyrene sulfonic acids, and poly aniline/ polystyrene sulfonic acid. Sulfonated columns can also be used with water glacial acetic acid mixtures, typically 90/10 (v/v). Polyacrylic acids run well on sulfonated gels in 0.2 M NaAc, pH 7.75. 

Absolute system calibration with a set of narrow distributed nb glucans (pullulans) by means of dual detection of mass and scattering intensity applying a mixed peak position/ broad standard calibration... 

FIGURE 16.10 Intial dextran calibration ( ) and resultingnb/Icbglucan calibration ( )forthe Sepha-cryl S-SOO/S-1000 (60 + 9S X 1.6 cm) system achieved from broad standard calibration with Dextran T-SOO and universal calibration, respectively Staudinger/Mark/Houwink constants (dextran Ksu = 0.0978 ml Mg . Osw = O.SO nb/lcb amylose = pullulan K pi. = 0.0268 ml M g . = 0.6S). 

The selective separation range of P-6/S-200 was determined with Blue Dextran (Vexdi exclusion limit) and fructose (V,o total permeation limit). Molecular weight (degree of polymerization) calibration (Fig. 16.22) was established with dextran standards and low dp pullulans (dp 3, 6, 9, 12, 15, 18) formed by the controlled hydrolysis of high dp pullulan. 

The strongest known producer of j8-poly(L-malic acid) has been identified as Aureobasidium sp. providing 61 g of polymer from 1 liter of culture medium [5,6]. 8-Poly(L-malate, Ca -salt) of the culture broth was first separated from accompanying bulk pullulan by methanol precipitation. The water-redisolved precipitate was converted to the polymer acid by passage over Amberlite IR-120B (H -form). Thus, the best to-day producers of... 

Most frequently, SEC with dextran-, pullulan-, or polystyrene calibration standards has been used to characterize the molecular properties of xylans. However, as for viscometric studies [108], a sufficient solvent ionic strength is a prerequisite for useful SEC measurements of charged polysaccharides, including glucuronoxylans [111-113]. An advantage of the SEC technique is that the presence of protein and phenolic components or oxidative changes can be detected by simultaneous ultraviolet (UV) detection. 

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