Xanthan Gum Production from Brazilian Trains

Abstract

Xanthan gum is an extracelullar polysaccharide obtained during fermentation of bacteria Xanthomonas sp. It is a biopolymer and consists of D-glucose, D-mannose and D-glucuronic acid units in the ratio of 3:3:2. It also contains acetyl and pyruvic acid groups. Xanthan gum dissolves readily in cold or hot water, turning into very viscous solution either if the concentration is small. Temperature and pH have very little effect on viscosity of the solutions. Due to these characteristics, xanthan gum is used as a thickening agent in foods and cosmetics, as an edible film-forming agent. It is used as and emulsifier in a wide variety of industrial processes, and is specially effective in secondary oil recovery operations.

In this paper we utilized xanthan gum obtained from Xanthomonas campestris pv manihots that showed to produce high quality gums in terms of viscosity, pH and temperature stability. Two strains were selected, and their growing and fermentation parameters were determined.

To grow the culture, two stages, of 24 hours each, were carried out in a medium containing glucose, malt extract, yeast extract and peptone at 25°C and 250 rpm.

The fermentation was carried out at 250 rpm, during 96 hours in a medium containing sucrose, dipotassium phosphate and magnesium sulphate. The temperature was set to 30°C and the pH to approximately 7.