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Characteristics and flocculating mechanism of a novel bioflocculant HBF-3 produced by deep-sea bacterium mutant Halomonas sp. V3a'

Author:
He, Jin, Zou, Juan, Shao, Zongze, Zhang, Jibin, Liu, Ziduo, Yu, Ziniu
Source:
World journal of microbiology & biotechnology 2010 v.26 no.6 pp. 1135-1141
ISSN:
0959-3993
Subject:
calcium chloride, sugars, calcium, chemical analysis, gel chromatography, pH, Halomonas, Fourier transform infrared spectroscopy, kaolin, mutants, molecular weight, bacteria
Abstract:
A novel bioflocculant HBF-3 produced by deep-sea bacterium mutant Halomonas sp. V3a' was investigated with regard to its flocculating characteristics and mechanism. 4.0 m g l⁻¹ HBF-3 showed the maximum flocculating activity of 96.9% in 5.0 g l⁻¹ Kaolin suspension containing 11.25 mM CaCl₂, and that its flocculating activity was more than 90% within 5-40°C and over 80% in a wide pH range (3.0-11.0). Chemical analyses indicated that the biopolymer HBF-3 was mainly a polysaccharide, including neutral sugar residues (20.6%), uronic acid residues (7.6%), amino sugar residues (1.6%) and sulfate groups (5.3%). Fourier transform infrared (FTIR) spectrum showed the presence of carboxyl and hydroxyl groups in HBF-3 molecular. The average molecular mass of HBF-3, as determined by gel filtration chromatography (GFC), was approximately 590 kDa. Flocculation of Kaolin suspension with HBF-3 acted as a model to explore the flocculating mechanism in which bridging mediated by Ca²⁺ was proposed as the primary action based upon the experimental observations.
Agid:
639984