Extremophiles

, Volume 9, Issue 3, pp 197–207

Permeability and reactivity of Thermotoga maritima in latex bimodal blend coatings at 80°C: a model high temperature biocatalytic coating

  • Olav K. Lyngberg
  • Chris Solheid
  • Salim Charaniya
  • Yue Ma
  • Venkata Thiagarajan
  • L. E. Scriven
  • Michael C. Flickinger
Original Paper

DOI: 10.1007/s00792-005-0434-7

Cite this article as:
Lyngberg, O.K., Solheid, C., Charaniya, S. et al. Extremophiles (2005) 9: 197. doi:10.1007/s00792-005-0434-7
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Abstract

Thermostable polymers cast as thin, porous coatings or membranes may be useful for concentrating and stabilizing hyperthermophilic microorganisms as biocatalysts. Hydrogel matricies can be unstable above 65°C. Therefore a 55-μm thick, two layer (cell coat + polymer top coat) bimodal, adhesive latex coating of partially coalesced polystyrene particles was investigated at 80°C using Thermotoga maritima as a model hyperthermophile. Coating permeability (pore structure) was critical for maintaining T. maritima viability. The permeability of bimodal coatings generated from 0.8 v/v of a suspension of non-film-forming 800 nm polystyrene particles with high glass transition temperature (Tg= 94°C, 26.9% total solids) blended with 0.2 v/v of a suspension of film-forming 158 nm polyacrylate/styrene particles (Tg≈ −5°C, 40.9% total solids) with 0.3 g sucrose/g latex was measured in a KNO3 diffusion cell. Diffusivity ratio remained above 0.04 (Deff/D) when incubated at 80°C in artificial seawater (ASW) for 5 days. KNO3 permeability was corroborated by cryogenic-SEM images of the pore structure. In contrast, the permeability of a mono-dispersed acrylate/vinyl acetate latex Rovace SF091 (Tg~10°C) rapidly decreased and became impermeable after 2 days incubation in ASW at 80°C. Thermotoga maritima were entrapped in these coatings at a cell density of 49 g cell wet weight/liter of coating volume, 25-fold higher than the density in liquid culture. Viable T. maritima were released from single-layer coatings at 80°C but accurate measurement of the percentage of viable entrapped cells by plate counting was not successful. Metabolic activity could be measured in bilayer coatings by utilization of glucose and maltose, which was identical for latex-entrapped and suspended cells. Starch was hydrolyzed for 200 h by latex-entrapped cells due to the slow diffusion of starch through the polymer top coat compared to only 24 h by suspended T. maritima. The observed reactivity and stability of these coatings was surprising since cryo-SEM images suggested that the smaller low Tg polyacrylate/styrene particles preferentially bound to the T. maritima toga-sheath during coat formation. This model system may be useful for concentrating, entrapment and stabilization of metabolically active hyperthermophiles at 80°C.

Keywords

Entrapped Thermotoga maritimaLatex coatingsBimodal polymer blendsLatex permeabilityThermostable biocatalytic coatings

Abbreviations

ASW

Artificial seawater

Deff/D

Ratio of the diffusivity of KNO3 in a latex coating relative to its diffusivity, D, in water

Tg

Polymer particle glass transition temperature

v/v

Volume fraction of bimodal latex emulsions blended

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Olav K. Lyngberg
    • 1
    • 2
    • 4
  • Chris Solheid
    • 2
  • Salim Charaniya
    • 2
  • Yue Ma
    • 1
    • 5
  • Venkata Thiagarajan
    • 2
  • L. E. Scriven
    • 1
  • Michael C. Flickinger
    • 2
    • 3
  1. 1.Department of Chemical Engineering and Materials ScienceUniversity of MinnesotaMinneapolisUSA
  2. 2.Biotechnology InstituteUniversity of MinnesotaSaint PaulUSA
  3. 3.Department of Biochemistry, Molecular Biology and BiophysicsUniversity of MinnesotaSaint PaulUSA
  4. 4.Bristol-Myers SquibbNew BrunswickUSA
  5. 5.Intel CorporationHillsboroUSA