Abstract: According to the characteristics of morphology, physiology and biochemistry and the comparison of 16S rDNA sequence, strain NX02 was identified as a new species of the genus Sphingomonas. A novel biopolymer synthesized by Sphingomonas sp. strain NX02 with thickening, pseudoplastic, gelling and emulsification. The results of qualitative analysis show that biopolymer is consisted of carbohydrates, lipids and peptides, the proportion is 34.8%, 63.1% and 1.5%, respectively. The weight average molar mass and number average molar mass of biopolymer was measured to be 408000 and 382000 by GPC-MALLS, and the polydiversity(M_w/M_n) was calculated to be 1.07. The monosaccharide compositions were glucose, mannose, rhamnose and glucuronic acid; the lipid portion was hexadecanoic acid and stearic acid; the proportion of glutamic acid and aspartic acid was 23.3% of the total amino acid content, so the polymer could be precipitated with acid, which reduced the production cost significantly.

Key words: Biopolymer, Molecular composition, Sphingomonas sp.