title: Production of extracellular water-insoluble polysaccharide from Pseudomonas sp.
abstract: Curdlan is a microbial polysaccharide composed exclusively of β-(1,3)-linked glucose residues. Until now only bacteria belonging to the  Alcaligenes  and  Agrobacterium  species have been reported to produce Curdlan. In this study, a bacterium capable of producing extracellular Curdlan, identified as  Pseudomonas  sp. on the basis of 16S rDNA gene sequencing, was isolated from soil samples. From the HPLC, permethylation linkage analysis, (13)C NMR, and FT-IR analytical data, the polysaccharide consisted exclusively of glucose; the most prominent sugar was 1,3-linked glucose, and most glycosidic bonds joining these sugar residues were of the β-type. This also supported that the exopolysaccharide produced by Pseudomonas sp. was actually Curdlan. In addition, the Pseudomonas sp. was studied for the production of Curdlan by conventional "one-factor-at-a-time technique" and response surface methodology (RSM). It was observed that glucose and yeast extract were the most suitable carbon source and nitrogen source for Curdlan production, respectively. By using RSM, Curdlan production was increased significantly by 188%, from 1.25 to 2.35 g/L, when the strain was cultivated in the optimal condition developed by RSM, and the highest Curdlan production rate of 0.81 g/(L h) was obtained. To the best of the authors' knowledge, this is the first report on Curdlan production by Pseudomonas sp.
authors.affiliation: Hebei Key Laboratory of Pharmaceutic Molecular Chemistry, Research Center for Fermentation Engineering of Hebei, College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhang, People's Republic of China. cjd007cn@163.com
authors.forename: Jian-Dong
authors.initials: JD
authors.lastname: Cui
authors.forename: Ji Qing
authors.initials: JQ
authors.lastname: Qiu
mesh_terms: D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010802:Phylogeny; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D012995:Solubility; D047071:beta-Glucans / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D047071:beta-Glucans; C038459:curdlan