Applied Microbiology and Biotechnology

, Volume 93, Issue 4, pp 1755–1767

Biological activity and mechanical stability of sol–gel-based biofilters using the freeze-gelation technique for immobilization of Rhodococcus ruber

  • Angela Pannier
  • Martin Mkandawire
  • Ulrich Soltmann
  • Wolfgang Pompe
  • Horst Böttcher
Environmental biotechnology

DOI: 10.1007/s00253-011-3489-7

Cite this article as:
Pannier, A., Mkandawire, M., Soltmann, U. et al. Appl Microbiol Biotechnol (2012) 93: 1755. doi:10.1007/s00253-011-3489-7

Abstract

Biofilters with long lifetime and high storage stability are very important for bioremediation processes to ensure the readiness at the occurrence of sudden contaminations. By using the freeze-gelation technique, living cells can be immobilized within a mechanically and chemically stable ceramic-like matrix. Due to a freeze-drying step, the embedded microorganisms are converted into a preserved form. In that way, they can be stored under dry conditions, which comply better with storage, transport, and handling requirements. Thus, in contrast to other immobilization techniques, there is no need for storage in liquid or under humid atmosphere. The biological activity, mechanical strength, and the structure of the biologically active ceramic-like composites (biocers) produced by freeze gelation have been investigated by using the phenol-degrading bacteria Rhodococcus ruber as model organism. Samples of freeze-gelation biocers have been investigated after defined storage periods, demonstrating nearly unchanged mechanical strength of the immobilization matrix as well as good storage stability of the activity of the immobilized cells over several months of storage at 4 °C. Repeated-batch tests demonstrated further that the freeze-gelation biocers can be repeatedly used over a period of more than 12 months without losing its bioactivity. Thus, these results show that freeze-gelation biocers have high potential of being scaled up from laboratory test systems to applications in real environment because of their long bioactivity as well as mechanical stability.

Keywords

Freeze cast Phenol degradation Bioremediation Cell encapsulation Compressive strength Tension strength 

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Angela Pannier
    • 1
  • Martin Mkandawire
    • 2
  • Ulrich Soltmann
    • 1
  • Wolfgang Pompe
    • 2
  • Horst Böttcher
    • 1
  1. 1.Department of Functional CoatingsGMBU e.V.DresdenGermany
  2. 2.Dresden University of Technology, Institute of Materials ScienceDresdenGermany