Dependence of the xanthan exopolysaccharide synthesis on the composition of the nutritional medium

Abstract

The possibility of changing the composition of the feed by replacing glucose with equivalent amounts of sucrose, starch, maltose was investigated. It was found that in the case of using sucrose, the kinematic viscosity of the culture liquid increased by more than 3 times. The replacement of ammonium sulphate in the composition of the nutrient medium with glycine, histidine and asparagine did not stimulate the growth of the producer and its synthesis of exopolysaccharide. At the same time, the replacement of citrate with fumarate made it possible to increase the concentration of biomass by 3 times and the kinematic viscosity of the samples by 8.5 times compared with the control. Based on the data obtained, it was proposed to optimize the composition of the nutrient medium by replacing citrate with fumarate and introducing sucrose-based feed instead of glucose. The study of the structural-dynamic state of EPS samples obtained during cultivation on an optimized nutrient medium using NMR relaxometry made it possible to detect a change in the xanthan structure.