Pullulan structure

Different morphologies of biopolymer-based encapsulation structures obtained through electrospinning, (a) Zein structures (b) PVOH fibers (c) pullulan structures (d) chitosan capsules. 

The products of hydrolysis by isopullulanase and T. vulgaris alpha amylase are in agreement with the structure previously established for pullulan. 

The research performed by several groups on pullulans has demonstrated their potential as nucleic acid delivery vehicles. Although most of the pullulan-based delivery systems yielded low toxicity, some modifications of the backbone or introduction of substituents resulted in higher toxicity. Such modifications are unavoidable because the parent structure is incapable of efficient delivery and lacks target specificity. 

FIGURE 1 Potential hydrolysis rates of six structurally distinct polysaccharides in seawater (A) and surface sediments (B) from Skagerrak and Svalbard. Pull = pullulan, lam = laminarin, xyl = xylan, fu = fucoidan, ara = arabinogalactan, chon = chondroitin sulfate. Note the differences in scale on the y axes for sediments and for seawater. [Skagerrak data from Arnosti (2000).]... 

McIntyre, D. D., and Vogel, H. J. (1993). Structural studies of pullulan by nuclear magnetic resonance. Starch/Staerke 45 406-410. 

Na, K., Lee, K. H., and Bae, Y. H. (2004), pH-sensitivity and pH-dependent interior structural change of self-assembled hydrogel nanoparticles of pullulan acetate/oligo-sulfonamide conjugate,/. Controlled Release, 97(3), 513-525. 

Crang, R. E. Pechak, D. G. (1978). Aureobasidium pullulans fine structure and development. Journal of Coatings Technology, 50, 36-42. 

Pullulanase is an extracellular enzyme of Aerobacter aerogenes that causes essentially quantitative hydrolysis of pullulan to maltotriose. The enzyme is readily prepared in a crude form that is free from other carbohydrases, and is important in structural studies because it debranches amylopectin and glycogen. When the A. aerogenes is grown in continuous culture, the enzyme is bound to the cells, but it can be released by detergents, and purified by ion-exchange chromatography. This purified enzyme has been crystallized. ... 

Hydrophobically modified polymers can associate in aqueous media to form micelle-like structures above their critical association concentrations (CACs). The nanosized self-aggregates were prepared using modified natural polysaccharides such as pullulan, curdlan, and glycol chitosan. The modified polysaccharides provide excellent biocompatibility, biodegradability, low immunogenicity, and biological activities. 

Pullulan [92] is produced in cultures of Aureobasidium sp., A. pullulans being primarily used. Its structure is that of a-maltotriosyl units linked (1 6) a few ( 6.6%) Q -maltotetraosyl units... 

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