title: Peptide-mediated microalgae harvesting method for efficient biofuel production.
abstract: BACKGROUND
  Production of biofuels from microalgae has been recognized to be a promising route for a sustainable energy supply. However, the microalgae harvesting process is a bottleneck for industrialization because it is energy intensive. Thus, by displaying interactive protein factors on the cell wall, oleaginous microalgae can acquire the auto- and controllable-flocculation function, yielding smarter and energy-efficient harvesting.
  
  
  RESULTS
  Towards this goal, we established a cell-surface display system using the oleaginous diatom Fistulifera solaris JPCC DA0580. Putative cell wall proteins, termed frustulins, were identified from the genome information using a homology search. A selected frustulin was subsequently fused with green fluorescent protein (GFP) and a diatom cell-surface display was successfully demonstrated. The antibody-binding assay further confirmed that the displayed GFP could interact with the antibody at the outermost surface of the cells. Moreover, a cell harvesting experiment was carried out using silica-affinity peptide-displaying diatom cells and silica particles where engineered cells attached to the silica particles resulting in immediate sedimentation.
  
  
  CONCLUSIONS
  This is the first report to demonstrate the engineered peptide-mediated harvesting of oleaginous microalgae using a cell-surface display system. Flocculation efficiency based on the silica-affinity peptide-mediated cell harvesting method demonstrated a comparable performance to other flocculation strategies which use either harsh pH conditions or expensive chemical/biological flocculation agents. We propose that our peptide-mediated cell harvest method will be useful for the efficient biofuel production in the future.
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Tateishi
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Niwa
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan ; JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, 102-0075 Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Muto
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yoshino
authors.affiliation: Department of Chemical and Environmental Engineering, University of California, Riverside, Room 343 Materials Science and Engineering Building, Riverside, CA 92521 USA.
authors.forename: David
authors.initials: D
authors.lastname: Kisailus
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan ; JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, 102-0075 Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanaka
keywords: Biofuel production; Cell-surface display; Diatom; Fistulifera solaris JPCC DA0580; Frustulin; Harvesting; Sedimentation; Silica-affinity peptide