Author(s)

Masakuni Tako^1,2*, Seiko kitajima¹, Takuya Yogi¹, Keiko Uechi¹, Masayuki Onaga¹, Yukihiro Tamaki¹, Shuntoku Uechi¹

¹Department of Subtropical Bioscience and Biotechnology, University of the Ryukyus, Okinawa, Japan.
²Health and Longevity Research Laboratory, Integrated Innovation Research Center, University of the Ryukyus, Okinawa, Japan.

The structure-function relationship of a gellan family of polysaccharides, S-198 gum produced by Alcaligenes ATCC31853 was investigated in terms of rheological aspects. The flow curves of S-198 gum showed plastic behavior above 0.3%. Gelation did not occur in S-198 gum solution at low temperature (0℃), even at 0.8%. Both the viscosity and the elastic modulus remained constant with increasing temperature up to 80?C. The elastic modulus decreased a little with the addition of CaCl2 (6.8 mM), but then once again remained constant up to 80℃. The highest elastic modulus was observed for deacylated gellan gum with the addition of CaCl2 and increased slightly with increasing temperature up to 80℃, which was considered to be a transition temperature, after which it decreased rapidly. The elastic modulus of S-198 gum in the presence of urea (4.0 M) was lower than that in aqueous solution at low temperature (0℃), but remained constant with increasing temperature up to 80℃. The intramolecular associations, (hydrogen bonding and van der Waals forces of attraction), of S-198 gum molecules in aqueous solutions were proposed. The gellan family of polysaccharides, S-198, S-88, S-657, rhamsan, welan and gellan gum, provided a good opportunity to investigate the structure-function relationship for polysaccharides.

S-198 Gum, Alcaligenes ATCC31853, Thermal Stability, Intramolecular Associations, Gellan Family of Polysaccharide

Tako, M. , kitajima, S. , Yogi, T. , Uechi, K. , Onaga, M. , Tamaki, Y. and Uechi, S. (2016) Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853. Advances in Biological Chemistry, 6, 55-69. doi: 10.4236/abc.2016.63007.