EPS production by Propionibacterium freudenreichii facilitates its immobilization for propionic acid production

Research output: Contribution to journalArticle


Aims: Immobilization of microbial cells is a useful strategy for developing high cell density bioreactors with improved stability and productivity for production of different chemicals. Functionalization of the immobilization matrix or biofilm forming property of some strains has been utilized for achieving cell attachment. The aim of the present study was to investigate the production of exopolysaccharide (EPS) by Propionibacterium freudenreichii C.I.P 59.32 and utilize this feature for immobilization of the cells on porous glass beads for production of propionic acid. Methods and Results: Propionibacterium freudenreichii was shown to produce both capsular and excreted EPS during batch cultivations using glucose as carbon source. Different electron microscopy techniques confirmed the secretion of EPS and formation of cellular aggregates. The excreted EPS was mainly composed of mannose and glucose in a 5·3 : 1 g g−1 ratio. Immobilization of the cells on untreated and polyethyleneimine (PEI)-treated Poraver beads in a bioreactor was evaluated. Higher productivity and yield of propionic acid (0·566 g l−1 h−1 and 0·314 g g−1, respectively) was achieved using cells immobilized to untreated beads and EPS production reached 617·5 mg l−1 after 48 h. Conclusion: These results suggest an important role of EPS-producing strains for improving cell immobilization and propionic acid production. Significance and Impact of the Study: This study demonstrates the EPS-producing microbe to be easily immobilized on a solid matrix and to be used in a bioprocess. Such a system could be optimized for achieving high cell density in fermentations without the need for functionalization of the matrix.


  • F. D.S. Belgrano
  • B. R.F. Verçoza
  • J. C.F. Rodrigues
  • R. Hatti-Kaul
  • N. Pereira
External organisations
  • Federal University of Rio de Janeiro
  • Lund University
  • Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemicals


  • biofilms, cell immobilization, exopolysaccharides, Propionibacterium, propionic acid
Original languageEnglish
Pages (from-to)480-489
Number of pages10
JournalJournal of Applied Microbiology
Issue number2
Publication statusPublished - 2018 Apr 28
Publication categoryResearch