Identification and characterization of coagulation inhibitor proteins derived from cyanobacterium Microcystis aeruginosa

Daisuke Sano, Shingo Ishifuji, Yuichi Sato, Yasutaka Imae, Tomoko Takaara, Yoshifumi Masago, Tatsuo Omura

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


The excess growth of cyanobacteria in semi enclosed water areas caused by eutrophication brings about coagulation inhibition in drinking water treatment processes. In this study, coagulation inhibitor proteins produced by Microcystis aeruginosa, a major cyanobacterium in algal bloom, were acquired by a phage display technique, an aluminum-immobilized affinity chromatography and a protein expression technique using Escherichia coli cells. Two cyanobacterial peptides with a high ratio of metallophilic amino acids were recovered, which were a part of homologues of a thiol oxidase enzyme Ero1p and a trans-acting repressor ArsR. It was also shown that the homologue of ArsR exhibited a stronger inhibitory effect on the coagulation of kaolin suspension with polyaluminum chloride than the control proteins. This is the first report to identify a cyanobacterial cell component to inhibit coagulation. The compositions of polar amino acids were critical to explain the strength of coagulation inhibition potential. Polar proteins from cyanobacteria could collectively consume coagulants or stabilize clay particles, which would be plausible explanations for causing coagulation inhibition. Meanwhile, results from the kaolin coagulation tests using the control proteins implied that the neutralization of positive charges of coagulant constituents by simple electrostatic interactions might not be the key mechanism on the protein-induced coagulation inhibition.

Original languageEnglish
Pages (from-to)1096-1102
Number of pages7
Issue number8
Publication statusPublished - 2011 Feb


  • Aluminum-immobilized affinity chromatography
  • Coagulation inhibition
  • Cyanobacterial protein
  • Microcystis aeruginosa
  • Phage display
  • Polyaluminum chloride


Dive into the research topics of 'Identification and characterization of coagulation inhibitor proteins derived from cyanobacterium Microcystis aeruginosa'. Together they form a unique fingerprint.

Cite this