ANALYSIS OF STRUCTURE AND FUNCTION OF GELLANS WITH DIFFERENT SUBSTITUTION PATTERNS

Chemical mutagenesis or exposure to antibiotic stress of Sphingomonas paucimobilis ATCC 31461 and R40 have been used to isolate mutants prod ucing modified gellan gum polysaccharides. N.m.r. and conventional car bohydrate analysis methods have been used to characterise these polysa ccharides. The H-1 and C-13 n.m.r. spectra of gellan gum have been ful ly assigned and the anomeric regions have been shown to be very sensit ive to the type and location of non-carbohydrate substituents. Analysi s of the gellan gum mutants suggests that they differ in the nature of acetate and glycerate substitution. Such gellan-related polysaccharid es have been used to test the selective effect of acyl substituents on the gelation of gellan gum. (C) 1997 Elsevier Science Ltd. All rights reserved.