title: Optimization of fermentation conditions and properties of an exopolysaccharide from Klebsiella sp. H-207 and application in adsorption of hexavalent chromium.
abstract: The novel exopolysaccharide HZ-7 is produced by Klebsiella sp. H-207, and its fermentation conditions were optimized by response surface methodology (RSM). In this study, the optimized medium consisted of sucrose 31.93 g/L, KNO(3) 2.17 g/L and K(2)HPO(4) 5.47 g/L; while the optimized culture conditions consisted of seed age 13 h, with an inoculum size of 10.6% and incubation temperature of 28.9°C. A maximum HZ-7 yield of about 15.05 g/L was achieved under the optimized conditions using RSM and single-factor experiments. Next the exopolysaccharide HZ-7 was partially purified and characterized. The resulting product showed good properties, such as high concentration of uronic acid (41.67%), low average molecular weight (about 1.94×10(5) Da) and porous surface structure, were very advantageous to biosorption. Therefore HZ-7 was applied to absorb hexavalent chromium (Cr(VI)). The maximum adsorption efficiency (99.2%) which was obtained at an initial pH of 1.0 along with an initial Cr(VI) concentration of 20 mg/L, was not affected by ordinary metal ions and temperature. These data suggest Klebsiella sp. H-207 exopolysaccharide will be promising potential for industrial application.
authors: School of Medicine and Life Sciences, University of Jinan, Jinan, China. chm_ lq@ujn.edu.cn
authors: Li
authors: L
authors: Qiang
authors: Li
authors: L
authors: Yumei
authors: Han
authors: H
authors: Sheng
authors: Liu
authors: L
authors: Yingzi
authors: Song
authors: S
authors: Dongxue
authors: Hao
authors: H
authors: Dake
authors: Wang
authors: W
authors: Jiajia
authors: Qu
authors: Q
authors: Yanhong
authors: Zheng
authors: Z
authors: Yuxia
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000302:isolation & purification* / Q000493:pharmacokinetics; D003470:Culture Media; D005285:Fermentation; D007218:Industrial Microbiology; D007709:Klebsiella / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry / Q000648:ultrastructure; D012722:Sewage / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000493:pharmacokinetics
chemical_list: D003470:Culture Media; D011135:Polysaccharides, Bacterial; D012722:Sewage; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion