title: Isolation and characterization of temperature and alkaline stable bioflocculant from Agrobacterium sp. M-503.
abstract: A bacterium isolated from activated sludge of propylene epoxide wastewater was identified as Agrobacterium sp. M-503. It was confirmed to produce bioflocculant with excellent flocculation activity. The yield of the bioflocculant reached 14.9 g/l in batch cultivation with a carbon source conversion of 74.5%. This bioflocculant was temperature and alkaline stable, retaining almost all flocculation activity after being treated at 121°C for 20 minutes or at pH 12.0. It consisted of neutral sugar, uronic acid, aminosugar and protein in weight ratios of 85.0:9.9:2.1:3.0. The active polysaccharide fraction of the bioflocculant was purified to homogeneity by ethanol precipitation, DEAE ion-exchange and gel chromatography. Analysis of the purified polysaccharide showed that it consisted of glucose residues and had a molecular weight of 8.1 × 10⁴ Da. Its low molecular weight endowed it with excellent solubility and favorable flocculation activity, especially for small particulates.
authors.affiliation: School of Medicine and Life Sciences, University of Jinan, Jinan, 250022, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Hong-lei
authors.initials: HL
authors.lastname: Liu
authors.forename: Qing-sheng
authors.initials: QS
authors.lastname: Qi
authors.forename: Feng-shan
authors.initials: FS
authors.lastname: Wang
authors.forename: Yu-zhen
authors.initials: YZ
authors.lastname: Zhang
mesh_terms: D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010316:Particle Size; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification*; D012231:Rhizobium / Q000737:chemistry / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D013696:Temperature
chemical_list: D011134:Polysaccharides; D012722:Sewage