The degradation of xanthan gum in ionic and non-ionic denaturants studied by rheology and molecular dynamics simulation

Osita Sunday Nnyigide; Tochukwu Olunna Nnyigide; Kyu Hyun

doi:10.1016/j.carbpol.2020.117061

The degradation of xanthan gum in ionic and non-ionic denaturants studied by rheology and molecular dynamics simulation

Carbohydr Polym. 2021 Jan 1:251:117061. doi: 10.1016/j.carbpol.2020.117061. Epub 2020 Sep 11.

Authors

Osita Sunday Nnyigide¹, Tochukwu Olunna Nnyigide¹, Kyu Hyun²

Affiliations

¹ School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, South Korea.
² School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, South Korea. Electronic address: kyuhyun@pusan.ac.kr.

PMID: 33142613
DOI: 10.1016/j.carbpol.2020.117061

Abstract

The use of xanthan gum (XG) as a thickener increases solution viscosity, and therefore, the cost of subsequent processes such as fluid transportation and purification. Herein, we investigate the degradation of XG by urea, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). The results showed that CTAB degraded the XG more than SDS or urea. Interestingly, the degree of CTAB-induced degradation varied with the concentration regime. Thus, increasing CTAB concentration from 0.01 to 0.1 M decreased the complex viscosity (|η*|), whereas from 0.2 to 0.5 M the |η*| increased. For XG/SDS, the |η*| was unchanged with increasing SDS concentration from 0.01 to 0.1 M, whereas it decreased from 0.2 to 0.5 M. For XG/urea, the |η*| was stable in all concentrations. At the atomic-scale, computer simulations revealed that the degrading effect of CTAB was due to preferential interaction with the XG sidechain. These findings can enhance industrial applications of XG.

Keywords: Molecular dynamics simulations; Rheology; Xanthan gum.