Isolation of oligogalacturonic acids in gram quantities by preparative h.p.l.c.

Abstract

Oligogalacturonic acids up to a degree of polymerization of 7 (d.p. 7) were isolated in gram quantities by preparative h.p.l.c. from endo-polygalacturonase- and pectate lyase-depolymerized polygalacturonic acid. A Dynamax-60A NH 2 (21.4 × 250 mm) 1-aminopropyl silica gel column was used with an isocratic acetate buffer (ca. 0.9 m, pH 5) mobile phase. Automated operation of the preparative h.p.l.c. system allowed for rapid, high-resolution separation and collection of oligogalacturonic acids that typically were 95–99% pure on a chromatographic peak area basis. The chromatographic system described represents an advance in oligogalacturonic acid isolation and purification methodology since it is faster, less labor intensive, and it provides higher isolation rates (over 300 mg/h of total oligosaccharides) than the traditionally used ambient pressure strong anion-exchange chromatography.