| The bioflocculant ZS-7 was purified to homogeneity by ethanol precipitation, dialysis and gel permeation chromatography (GPC). About 0.98 g of the purified bioflocculant could be recovered from 1L of fermentation broth. The purified bioflocculant was identified as a glycoprotein consisting of polysaccharide (91.5%) and protein (8.4%), with an approximate molecular weight of 6.89 × 104. The major component of ZS-7 is an acid polysaccharide including uronic (16.4%), pyruvic (7.1%) and acetic acids (0.5%). It consists of galactose, glucose, mannose and rhamnose in a molar ratio of 142∶2.2∶4.5∶3.4. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) and NMR spectrum of the bioflocculant indicate the presence of carboxyl, hydroxyl, amide, amino, methoxyl and sulfate groups. |
