Structural studies of the glucuronic acid oligomers produced
by Gluconacetobacter hansenii strain
Joong Kon Park
*
, Taous Khan, Jae Yong Jung
Department of Chemical Engineering, Kyungpook National University, Buk-ku Sankyuk-dong 1370, Daegu 702-701, South Korea
Received 4 May 2005; received in revised form 20 August 2005; accepted 5 October 2005
Available online 9 November 2005
Abstract
Gluconacetobacter hansenii PJK, a cellulose producing bacterium recently isolated from the rotten apples, produced fair amounts of the water-
soluble polysaccharides (WSPS). WSPS were studied for their monosaccharides composition after acid hydrolysis, which revealed that the
hydrolysates consist only of one sugar, glucuronic acid. The structure of the WSPS was investigated using various spectroscopic techniques
including FT-IR, MALDI-TOF MS and
1
H, and
13
C NMR. These studies revealed that the product is a mixture of oligomers with the a-glucuronic
acid as building blocks. The possible structure of the major oligosaccharide in the mixture has been deduced.
q 2005 Published by Elsevier Ltd.
Keywords: Gluconacetobacter hansenii PJK; Water-soluble polysaccharides; Glucuronic acid; Spectroscopic techniques
1. Introduction
Microbial fermentation is a source for the production of
food polysaccharides, although most polysaccharides derived
from plants and seaweeds are used in industry (European
Commission, 2000). Bacterial exopolysaccharides (EPS)
generally have unique rheological properties caused by their
high purity and regular structure. Therefore, the food industry
frequently uses EPS as thickening, gelling, or stabilizing agents
(Kornmann, Duboc, Marison, & Stockar, 2003). The discovery
of immune modulation and tumouristasis by b-
D
-glucans
provides some novel applications of EPS (Sutherland, 1998).
Biopolymers production by bacterial fermentation is a
potential alternative to petrochemical and vegetal polymers
due to their wide diversity and the possibility of specific
structural changes induced by controlled culture conditions in
bioreactors (Brou, Jaffrin, Ding, & Courtois, 2003).
Polysaccharides, including glucuronan, which contain
carboxyl groups, are valuable compounds because their
enveloping and/or resolving activity makes them suitable as
carriers for various active substances, and as solvents,
stabilizers, binders, swelling agents, and so on (Antonius &
Cornelis, 1991). Conservation of the carbon skeleton in the
oxidized polysaccharide is often advantageous for achieving
the complexing or stabilizing activity (Antonius & Cornelis,
1991). The medical properties of oxidized celluloses to stop
bleeding during surgery, to prevent the formation and
reformation of post-surgical adhesions, to promote anti-
bacterial activity, to promote bone regeneration, and their
usefulness in periodontal therapy have been attributed to
the glucuronan structure of such compounds (Kumar &
Dong, 2002).
Many EPS, derived from microbial origin, contain
glucuronic acid moieties in their structure (Takemura, Tabuchi,
Watanabe, Tsuchida, Morinaga and Sone, 1995; Tayama,
Minakami, Entani, Fujiyama, & Massai, 1985; Valla &
Kjosbakken, 1981) or are the homopolymers of glucuronic
acid (Courtois, Courtois, Heyraud, Colin-Morel, & Rinaudo,
1992; Courtois, Seguin, Declomesnil, Heyraud, Colin-Morel
and Dantas, 1993; Dantas, Courtois, Courtois, Seguin, Gey and
Heyraud, 1994; Lintner, 1999; Michaud, Courtois, Courtois,
Heyraud, Colin-Morel and Seguin, 1994). The EPS produced
by the Rhizobium meliloti MN1CS strain (Courtois et al., 1992)
is a linear homopolymer of partially acetylated glucuronic acid
(Courtois et al., 1993) and can be used as a substitute for pectin
and alginate in the food or cosmetic industry because of its
remarkable gelling or thickening properties (Lintner, 1999).
The oligoglucuronans obtained by degradation of the polymer
by enzymatic action present biological activities such as root
growth promoting activity and bacteriostasis (Iwasaki &
Matsubara, 2000; Kitamikado, Nishimura, Yamaguchi, &
Tseng, 1993).
Carbohydrate Polymers 63 (2006) 482–486
www.elsevier.com/locate/carbpol
0144-8617/$ - see front matter q 2005 Published by Elsevier Ltd.
doi:10.1016/j.carbpol.2005.10.004
*
Corresponding author. Tel.: C82 53 950 5615; fax: C82 53 950 6615.
E-mail address: parkjk@kyungpook.ac.kr (J.K. Park).