Document Detail

Permeability and reactivity of Thermotoga maritima in latex bimodal blend coatings at 80 degrees C: a model high temperature biocatalytic coating.
MedLine Citation:
PMID:  15778817     Owner:  NLM     Status:  MEDLINE    
Thermostable polymers cast as thin, porous coatings or membranes may be useful for concentrating and stabilizing hyperthermophilic microorganisms as biocatalysts. Hydrogel matrices can be unstable above 65 degrees C. Therefore a 55-microm thick, two layer (cell coat + polymer top coat) bimodal, adhesive latex coating of partially coalesced polystyrene particles was investigated at 80 degrees 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 (T(g) = 94 degrees C, 26.9% total solids) blended with 0.2 v/v of a suspension of film-forming 158 nm polyacrylate/styrene particles (T(g) approximately -5 degrees 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 (D(eff)/D) when incubated at 80 degrees 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 (T(g) approximately 10 degrees C) rapidly decreased and became impermeable after 2 days incubation in ASW at 80 degrees 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 degrees 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 T(g) 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 degrees C.
Olav K Lyngberg; Chris Solheid; Salim Charaniya; Yue Ma; Venkata Thiagarajan; L E Scriven; Michael C Flickinger
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.     Date:  2005-03-19
Journal Detail:
Title:  Extremophiles : life under extreme conditions     Volume:  9     ISSN:  1431-0651     ISO Abbreviation:  Extremophiles     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-06-10     Completed Date:  2005-12-15     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9706854     Medline TA:  Extremophiles     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  197-207     Citation Subset:  IM; S    
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
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MeSH Terms
Cryoelectron Microscopy
Hot Temperature
Thermotoga maritima / growth & development,  physiology*,  ultrastructure
Grant Support
Reg. No./Substance:

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