title: Screening and characterization of a bioflocculant produced by Aeromonas sp.
abstract: OBJECTIVE
  To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant.
  
  
  METHODS
  Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant.
  
  
  RESULTS
  A novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. N11. Flocculating activity increased in the presence of K+, Na+, or Ca2+. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K+, Ca+, and Na+ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mgxL(-1), and its activity in kaolin suspension was decreased by only 9.2% after heating at 100 degrees C for 60 min.
  
  
  CONCLUSIONS
  The bioflocculant produced by Aeromonas sp. N11 has strong flocculating activity and high stability, which affords high possibility of its practical use.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan, China. xmli@hnu.cn
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Kai
authors.initials: K
authors.lastname: Huang
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Zeng
authors.forename: De-Xiang
authors.initials: DX
authors.lastname: Liao
authors.forename: Jin-Jing
authors.initials: JJ
authors.lastname: Liu
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Long
mesh_terms: D000333:Aeromonas / Q000378:metabolism*; D003470:Culture Media; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007616:Kaolin
chemical_list: D003470:Culture Media; D007616:Kaolin