Akira Takei

Extracellular polysaccharides produced by tuberose callus

A high yield of extracellular polysaccharide (ECP) was obtained from callus cultures of tuberose (Polianthes tuberosa), which could be separated into an unadsorbed and two acidic fractions (TPS-1, -2) by ion-exchange column chromatography. The yields of each fraction were markedly increased by the addition of 10(-5) M 2,4-dichlorophenoxyacetic acid to the medium. Of the three fractions, the amount of TPS-1 accounted for over 60% of total yield of ECP, which was a predominant polysaccharide consisting of arabinose (Ara), mannose (Man) and galactose (Gal) as major neutral monosaccharides. Judging from the patterns of electrophoresis and ultra-centrifugation, TPS-1 was identified to be homogeneous. Methylation and GC-mass spectrometry analyses of this fraction revealed the presence of 1,2,3-linked Man, 1-linked Ara, 1,3-linked Ara, 1-linked Gal and 1,3,4-linked glucuronosyl (GlcUA) residues in a molar ratio of 1.0:1.08:0.85:0.75:1.08. Based on additional analyses of the mild acid hydrolysate and the absolute configuration of the constituent monosaccharides, a possible structure for TPS-1 was a glucuronomannan possessing the unit of -->4)-beta-D-GlcUAp-(1-->2)-alpha-D-Manp-(1--> with branching at the C-3 position, where -->1)-alpha-L-Araf, -->1)-beta-D-galp, -->1)-alpha-L-Araf-(3-->1)-alpha-L-Araf or -->1)-alpha-L-Araf-(3-->1)-beta-D-Galp were attached randomly. About 35% of the GlcUA moieties were present as methyl esters. Further confirmation was made by 1H and 13C NMR spectroscopy.

Production of polysaccharides by liquid cultures of Polianthes tuberosa cells; high production by reduction in the viscosity of culture medium

To improve the production of extracellular polysaccharides (EPS) in liquid cultures of Polianthes tuberosa (tuberose) cells, the viscosity of the culture medium was lowered by addition of mineral salts. In cultures in the medium supplemented with 30 mM CaCl2, higher production of EPS (6.5g/l) has been realized (vs. 4.6 g/l without CaCl2).

Production of polysaccharides in liquid cultures of Polianthes tuberosa cells

SummaryThe effects of components of the medium on the production of extracellular polysaccharide (EPS) by cultured cells of Polianthes tuberosa (tuberose) were studied. Optimization of media components culturing in flask resulted in increasing EPS production from 1.4 to 4.1 g/l. In particular, relatively high concentration (10\s-5M) of 2,4-dichlorophenoxyacetic acid (2,4-D) markedly stimulated the production of EPS. Based on these results, EPS production by a 30-1 jar fermenter was attempted and the final rate of Production was 4.6 g/l at 30th day of culture. The EPS consisted mainly of acidic polysaccharides with glucuronic acid, mannose, arabinose, galactose, glucose and xylose.