产碱杆菌NX-3胞外多糖的结构与性能

Structural and Characteristics of Exopolysaccharide Produced by Alcaligenes sp.NX-3

一株产碱杆菌NX-3分泌的可溶性胞外多糖(PS-238)经醇析、Sevag法脱蛋白、透析、冷冻干燥得分析样品,酸水解后经TLC、GC以及化学法、IR和高碘酸氧化分析测得PS-238是由葡萄糖、甘露糖、鼠李糖和葡萄糖醛酸组成的杂多糖,糖苷键类型主要为(1→3)和(1→4).此外考察多糖溶液粘度与剪切速率、溶液浓度、温度、酸碱度以及盐离子种类和浓度等因素之间的关系,结果表明多糖水溶液的流体特征表现为假塑型,25℃时1%的水溶液粘度可达3,300cp,耐酸碱,在pH2～13的范围内粘度稳定;耐高温,在150℃内不发生明显降解;部分盐类对PS-238的增稠性有协同效应.

The structure and characteristics of the soluble exopolysaccharide （PS-238） produced by Alcaligenes sp. NX-3 were studied. The analytic sample was prepared by ethanol precipitation then proteins were removed by the Sevag method. The components of polysaccharide were identified by TLC, GC and chemical method after acid hydrolysis as： glucose, mannose, rhamnose and glucuronic acid. By means of IR and periodate oxidation, it showed that the polysaccharide was mainly consisting of （ 1→3 ） and （1→4） glucosidic linkages. The relation between viscosity and shear rate 、 concentration, temperature, pH and salts was investigated. The results showed that the solution of PS-238 is a typical pseudoplastic liquid, having high viscosity at low concentrations. The viscosity of 1% PS-238 water solution could reach 3,300cp at 25℃. It has the excellent stability towards pH2 - 13, also has outstanding property of viscosity retention even at temperatures up to 150℃ Some kinds of salts were cooperated with PS-238 as a thickening agent.