title: Characterization of a bioflocculant produced by the marine myxobacterium Nannocystis sp. NU-2.
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 Fe(3+) and Al(3+). When a 30 mg l(-1) FeCl(3) solution is present in kaolin clay suspension, 30 mg l(-1)of 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(-1)of the flocculant and 99.0% for direct emerald blue in 50 mg l(-1)of the flocculant under test conditions. Use of the flocculant to bleach basic pink and cation emerald blue liquors was not effective.
authors.affiliation: Department of Biology, Nanjing University, Nanjing 210092, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: P
authors.initials: P
authors.lastname: Jiang
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001709:Biotechnology / Q000379:methods; D004275:DNA, Ribosomal / Q000032:analysis; D005427:Flocculation; D005456:Fluorescent Dyes / Q000737:chemistry; D008969:Molecular Sequence Data; D009231:Myxococcales / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010802:Phylogeny; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012235:Rhodamines / Q000737:chemistry; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004275:DNA, Ribosomal; D005456:Fluorescent Dyes; D011135:Polysaccharides, Bacterial; D012336:RNA, Ribosomal, 16S; D012235:Rhodamines; C022027:lissamine rhodamine B