Pullulan Elaboration by Aureobasidium pullulans Protoplasts

Abstract

Protoplasts of Aureobasidium pullulans are capable of producing pullulan. Biosynthesis of the polymer pullulan required induction with kinetics similar to those of whole cells. The protoplasts also produced a heteropolysaccharide component containing mannose, glucose, and galactose. The relative proportions of the pullulan and heteropolysaccharide fractions were a function of glucose concentration, with the pullulan content of the total polysaccharide rising from 20% at 2.5 mM glucose to 45% at 20 mM glucose. Elaboration of pullulan by both cells and protoplasts was sensitive to 0.6 M KCl, which was present as the osmotic stabilizer in protoplast experiments. The presence of KCl resulted in a shift in the pH optimum to a more acidic value. The molecular weight of the protoplast-derived pullulan was sharply reduced from the molecular weight of the whole-cell-derived product. Exposure of the protoplasts to proteolytic enzymes had no effect on polysaccharide elaboration.

Recent advances in radical polymerization of bio-based monomers in aqueous dispersed media

“…Both are bio-sourced because the production of AA by fermentation from 3-hydroxypropionic acid is widely described on the laboratory scale 80 and THG is a natural terpenoid. The second copolymer was made by the amidation reaction between a hydrophilic polysaccharide, carboxymethylpullulan (CMP) produced from pullulan, a natural polysaccharide derived from starch 81 and a hydrophobic part composed of a dihydromyrcenol (DHM) terpenoid amino-derivative. The newly synthesized amphiphilic copolymers were employed as stabilizers in the miniemulsion (co)polymerization of β-myrcene and styrene.…”