The relationship between monosaccharide composition of extracellular polysaccharide and activities of related enzymes in Nostoc flagelliforme under different culture conditions

The relationship between monosaccharide composition of Nostoc flagelliforme extracellular polysaccharide (EPS) and activities of EPS synthesis enzymes under various carbon sources, nitrogen sources and light culture condition was investigated. Culture conditions showed significant influences on both monosaccharide composition and related enzyme activities. Under both carbon and nitrogen sources conditions, mannose mole percentage was increased with the increase of initial mole ratio of C/N and positively related to fructose-1, 6-bisphosphatase activity, and glucuronic acid and galactose mole percentages were positively correlated with UDP-glucose dehydrogenase, while arabinose and rhamnose mole percentages were negatively associated with UDP-glucose pyrophosphorylase. Different correlation between monosaccharide composition and enzymes activity from carbon and nitrogen sources conditions was found under light condition. These findings will be helpful to establish a novel fermentation process aimed to produce the N. flagelliforme EPS with desired monosaccharide composition. (C) 2017 Elsevier Ltd. All rights reserved.