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Optimization of fermentation conditions and properties of an exopolysaccharide from Klebsiella sp. H-207 and application in adsorption of hexavalent chromium.

Qiang L, Yumei L, Sheng H, Yingzi L, Dongxue S, Dake H, Jiajia W, Yanhong Q, Yuxia Z - PLoS ONE (2013)

Bottom Line: 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)).These data suggest Klebsiella sp.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine and Life Sciences, University of Jinan, Jinan, China. chm_ lq@ujn.edu.cn

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.

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The effects of various parameters on Cr(VI) adsorption.A, initial pH; B, temperature (°C); C, adsorption time (min); D, initial concentration of Cr(VI) (mg/L). Each bar represented the mean± SD of three replicates.
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pone-0053542-g007: The effects of various parameters on Cr(VI) adsorption.A, initial pH; B, temperature (°C); C, adsorption time (min); D, initial concentration of Cr(VI) (mg/L). Each bar represented the mean± SD of three replicates.

Mentions: The effect of the initial pH value on Cr(VI) adsorption was investigated by adjusting the solution pH to 0.5, 1.0, 1.5, 2.0, 2,5 and 3.0 with 1 M HCl. The results shown in Figure 7A demonstrated a strong adsorption under acid conditions, and the adsorption efficiency of Cr(VI) reached its maximum value (99.2%) at pH 1.0. The low constant adsorption efficiency (about 50%) was achieved at higher pH. High adsorption efficiency observed at lower pH may be attributed due to electrostatic interactions between adsorbent and adsorbate. More specifically, the increase in H+ concentration left the HZ-7 surface with less negative charges, meanwhile, the dominating Cr(VI) form was the negatively charged Cr2O7−[29].


Optimization of fermentation conditions and properties of an exopolysaccharide from Klebsiella sp. H-207 and application in adsorption of hexavalent chromium.

Qiang L, Yumei L, Sheng H, Yingzi L, Dongxue S, Dake H, Jiajia W, Yanhong Q, Yuxia Z - PLoS ONE (2013)

The effects of various parameters on Cr(VI) adsorption.A, initial pH; B, temperature (°C); C, adsorption time (min); D, initial concentration of Cr(VI) (mg/L). Each bar represented the mean± SD of three replicates.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539975&req=5

pone-0053542-g007: The effects of various parameters on Cr(VI) adsorption.A, initial pH; B, temperature (°C); C, adsorption time (min); D, initial concentration of Cr(VI) (mg/L). Each bar represented the mean± SD of three replicates.
Mentions: The effect of the initial pH value on Cr(VI) adsorption was investigated by adjusting the solution pH to 0.5, 1.0, 1.5, 2.0, 2,5 and 3.0 with 1 M HCl. The results shown in Figure 7A demonstrated a strong adsorption under acid conditions, and the adsorption efficiency of Cr(VI) reached its maximum value (99.2%) at pH 1.0. The low constant adsorption efficiency (about 50%) was achieved at higher pH. High adsorption efficiency observed at lower pH may be attributed due to electrostatic interactions between adsorbent and adsorbate. More specifically, the increase in H+ concentration left the HZ-7 surface with less negative charges, meanwhile, the dominating Cr(VI) form was the negatively charged Cr2O7−[29].

Bottom Line: 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)).These data suggest Klebsiella sp.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine and Life Sciences, University of Jinan, Jinan, China. chm_ lq@ujn.edu.cn

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.

Show MeSH
Related in: MedlinePlus