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Partial characterization and flocculating behavior of an exopolysaccharide produced in nutrient-poor medium by a facultative oligotroph Klebsiella sp. PB12

Paper ID Volume ID Publish Year Pages File Format Full-Text
20963 43199 2013 6 PDF Available
Title
Partial characterization and flocculating behavior of an exopolysaccharide produced in nutrient-poor medium by a facultative oligotroph Klebsiella sp. PB12
Abstract

A facultative oligotrophic strain from the water sample of River Mahananda, Siliguri India was selected for its property to produce exopolysaccharide (EPS) in nutrient-poor (oligotrophic) medium. Viability assay of the strain was performed in sterile liquid LB, R2A, river water and diluted (10−3) LB at 30°C and pH 7 to understand oligotrophy. The selected strain was identified by 16S rRNA gene sequencing and designated as Klebsiella sp. PB12. Phylogenetic analysis showed its closest relationship with Klebsiella variicola ATCC BAA-830T. Purification of EPS was performed by ethanol precipitation, dialysis and freeze-drying. Chemical analysis revealed that purified EPS was mainly composed of 72.32% (w/w) neutral sugar and 14.12% (w/w) uronic acids. Fourier transform infrared (FT-IR) spectroscopy indicated the presence of hydroxyl, carboxylic and methoxyl functional groups. The optimal dosages for flocculation of activated carbon suspension were 17 mg/l EPS and 4 mM CaCl2. EPS showed flocculating rate of above 80% over a wide range of pH (pH 3–10) whereas, more than 90% rate was noted in the temperature range (10–50°C) tested in presence of CaCl2. Moreover, EPS showed characteristic emulsifying activity with toluene (66.6%), n-hexadecane (65%), olive oil (63.3%) and kerosene (50%). The apparent molecular weight of the EPS was ∼2 × 105 Da.

Keywords
Exopolysaccharide (EPS); Klebsiella sp. PB12; Oligotrophic bacteria; Fourier transform infrared (FT-IR); Flocculating rate
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Partial characterization and flocculating behavior of an exopolysaccharide produced in nutrient-poor medium by a facultative oligotroph Klebsiella sp. PB12
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 115, Issue 1, January 2013, Pages 76–81
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us