Elucidation of the biosynthetic mechanisms of chitosan-like bioflocculant and its high production by metabolic engineering

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K06586
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biofunction/Bioprocess
• Research Institution: University of Hyogo
• Principal Investigator: Masahiro Takeo 兵庫県立大学, 工学研究科, 准教授 (40236443)
• Co-Investigator(Renkei-kenkyūsha): NEGORO Seiji 兵庫県立大学, 大学院工学研究科, 教授 (00301432)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: bioflocculant / Citrobacter / Metabolic engineering / secretion / memebrane concentration / chitosan

Outline of Final Research Achievements

To elucidate the biosynthetic mechanisms of chitosan-like bioflocculant produced by Citrobacter strains and to improve the production, gene addition/disruption studies were performed on genes involved in amino sugar biosynthesis, glucose metabolisms, and polymerization and secretion of the bioflocculant (bfpABCD) in C. freundii IFO 13545. By these trials, the gene modified strains increased the activities, which achieved to 7-times higher activity than that of the wild type strain. To understand the functions of bfpABCD, BfpB, a putative deacetylase, was over-expressed in E. coli and purified. However, the protein showed no deacetylating activity against the bioflocculant. For the recovery of the bioflocculant from the culture supernatants, membrane concentration was also conducted using hollow fiber membrane modules.

Free Research Field

生物工学