Applied Microbiology and Biotechnology

, Volume 59, Issue 4–5, pp 517–522 | Cite as

Characterization of a bioflocculant produced by the marine myxobacterium Nannocystis sp. NU-2

  •  J. Zhang
  •  Z. Liu
  •  S. Wang
  •  P. Jiang
Original Paper

Abstract.

The marine myxobacterium strain NU-2, which can grow on high concentrations (up to 7%) of NaCl, was isolated from a salt soil sample collected from the coast of the Huanghai Sea, China. Morphological properties and 16S rDNA sequence analysis indicated that the isolate is a novel species related to the genus Nannocystis. Nannocystis sp. NU-2 produced a new kind of flocculating substance in a starch medium with a yield of 14.8 g l–1. The NU-2 flocculant was composed of 40.3% proteins and 56.5% polysaccharides, of which glucose, mannose and glucuronic acid were the principal constituents in the relative proportions of 5:4:1. The flocculation activity of the NU-2 flocculant depends strongly on cations such as Fe3+ and Al3+. When a 30 mg l–1 FeCl3 solution is present in kaolin clay suspension, 30 mg l–1of the flocculant produced a high flocculating activity value of 90%, which remained unchanged over an extensive pH range (pH 2.0–13.0). The flocculant was tested for its ability to bleach dyeing liquors, and the bleaching activities were 98.2% for acid red in 100 mg l–1of the flocculant and 99.0% for direct emerald blue in 50 mg l–1of the flocculant under test conditions. Use of the flocculant to bleach basic pink and cation emerald blue liquors was not effective.

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  J. Zhang
    • 1
  •  Z. Liu
    • 1
  •  S. Wang
    • 2
  •  P. Jiang
    • 2
  1. 1.Department of Biology, Nanjing University, Nanjing 210092, PR China
  2. 2.Department of Environmental Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China

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