| 摘要 |
Process for preparing an exocellular polysaccharide comprises cultivating Pseudomonas sp. NCIB 11264 (ATCC 31260). Polysaccharides are formed from a repeating unit contg. 7 gluco-D units comprising 1 glucose unit substd. in the 6-posn., 2 glucose units substd. in posn. 4, 2 glucose units substd. in posn. 3, and 2 glucose units substd. in positions 4 and 6; 1 galacto-D unit comprising galactose substd. in position 3; 1 acetate and pyruvate unit; the units contain a branch point on the 4,6-disubstd. glucose and a lateral chain terminating in a 4,6-O-(1-carboxyethylidene)-glucose-D unit. The polysaccharide has an optical rotation a 22 of -15 degrees (C 0.68H2O). The polysaccharides have remarkable pseudoplastic flow properties and shearing fluidisation properties compared with xanthanes and alginates. |
