TY - JOUR
T1 - Characterisation and modification of the exopolysaccharide produced by Lactococcus lactis subsp. cremoris B40.
AU - van Casteren, W.H.M.
AU - Dijkema, C.
AU - Schols, H.A.
AU - Beldman, G.
AU - Voragen, A.G.J.
PY - 1998
Y1 - 1998
N2 - The chemical structure of an exopolysaccharide produced by Lactococcus lactis subsp. cremoris B40 is studied, explaining earlier reported analytical discrepancies. The EPS was found to have a molecular mass of 6.8x105gmol-1 and a molar ratio of rhamnose:galactose:glucose:phosphorus of 1:1.3:2:1.1. 31P NMR indicated that a single phosphate group is present as a phosphodiester. EPS B40 was chemically modified using 0.6M H2SO4, 28M HF or 2M NaOH. From these modifications it could be concluded that galactose 1-phosphate was linked at the 3-position of 1,2,3,4-linked galactose in the backbone of the EPS. Furthermore, it appeared that during the hydrolysis step of the sugar composition analysis the galactose 3-phosphate linkages were only partially split and that, as a result, the amount of galactose was underestimated in presence of phosphate. Finally, it was demonstrated that a crude cellulase preparation was able to degrade dephosphorylated and partially de-rhamnosylated EPS.
AB - The chemical structure of an exopolysaccharide produced by Lactococcus lactis subsp. cremoris B40 is studied, explaining earlier reported analytical discrepancies. The EPS was found to have a molecular mass of 6.8x105gmol-1 and a molar ratio of rhamnose:galactose:glucose:phosphorus of 1:1.3:2:1.1. 31P NMR indicated that a single phosphate group is present as a phosphodiester. EPS B40 was chemically modified using 0.6M H2SO4, 28M HF or 2M NaOH. From these modifications it could be concluded that galactose 1-phosphate was linked at the 3-position of 1,2,3,4-linked galactose in the backbone of the EPS. Furthermore, it appeared that during the hydrolysis step of the sugar composition analysis the galactose 3-phosphate linkages were only partially split and that, as a result, the amount of galactose was underestimated in presence of phosphate. Finally, it was demonstrated that a crude cellulase preparation was able to degrade dephosphorylated and partially de-rhamnosylated EPS.
KW - Chemical structure
KW - Exopolysaccharide
KW - Lactococcus
KW - Modification
KW - Phosphorus
U2 - 10.1016/S0144-8617(98)00044-7
DO - 10.1016/S0144-8617(98)00044-7
M3 - Article
SN - 0144-8617
VL - 37
SP - 123
EP - 130
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
ER -