Microstructure Evolution in Polymer Latex Coatings for Whole-Cell Biocatalyst Application

Huang, Zhisong; Thiagarajan, V.; Lyngberg, Olav; Scriven, L. E.; Flickinger, Michael C.

doi:10.1006/jcis.1999.6178

Cited by 24 publications

(47 citation statements)

References 6 publications

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“…This, we conclude, is because part of the retained glycerol is sequestered inside the cells and is unavailable to be extruded or to effect changes in the latex particle coalescence or film structure. No specks of extruded material, possibly stabilizer, of the sort seen in the cell-free and glycerol-free coatings (13) are seen even after 4 -8 h of drying. This suggests that film formation is proceeding more slowly.…”

Section: Dry Cell Coats With Glycerolmentioning

confidence: 95%

“…Coatings were examined in a JEOL 840 scanning electron microscope as detailed by Huang et al (13). Figure 2 shows the top surface of the polydisperse latex cell coat as drying and film formation progressed at 30°C in a desiccator.…”

Section: Cryo-semmentioning

confidence: 99%

“…The cell coat mixtures were coated onto primed stainless steel shims or precleaned silicon wafers using Mayer rod drawdown coating as described for the topcoats (13). For rehydrated samples, the coatings were dried for 30 min at 30°C in a desiccator, 5 mm ϫ 7 mm coupons were cut and transferred to 10 ml of PBS in 50-ml disposable tubes, and the tubes were shaken at 150 rpm in an orbital shaker (Labline Co.).…”

Section: Coatingmentioning

confidence: 99%

“…We report here the microstructure of two biocatalytic acrylic acid/vinyl acetate latex coatings and the effect of glycerol in these coatings, as elucidated by cryo-SEM. This paper details the microstructure of the cell coats and the companion paper (13) details that of the topcoats which serve to retain cells in the cell coat while allowing transport of reactants and products to and from the viable and catalytically active bacterial cells.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Thiagarajan

Huang

Scriven

et al. 1999

Journal of Colloid and Interface Science

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Section: Dry Cell Coats With Glycerolmentioning

confidence: 95%

Section: Cryo-semmentioning

confidence: 99%

Section: Coatingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Thiagarajan

Huang

Scriven

et al. 1999

Journal of Colloid and Interface Science

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“…17 These biocatalytic coatings are unique because of the high cell viability following coating rehydration despite the film formation and drying process. In addition to acting as porogens, the carbohydrates added to the latex formulation impart desiccation tolerance to the entrapped cells as the coatings dry due to a glass transition resulting in vitrification of extracellular and intracellular carbohydrates and ions which form stabilizing complexes preserving metabolically active but dormant cells.…”

mentioning

confidence: 99%

Progress toward a biomimetic leaf: 4,000 h of hydrogen production by coating‐stabilized nongrowing photosynthetic Rhodopseudomonas palustris

Gosse

Engel

Hui

et al. 2010

Biotechnology Progress

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Intact cells are the most stable form of nature's photosynthetic machinery. Coating-immobilized microbes have the potential to revolutionize the design of photoabsorbers for conversion of sunlight into fuels. Multi-layer adhesive polymer coatings could spatially combine photoreactive bacteria and algae (complementary biological irradiance spectra) creating high surface area, thin, flexible structures optimized for light trapping, and production of hydrogen (H(2)) from water, lignin, pollutants, or waste organics. We report a model coating system which produced 2.08 +/- 0.01 mmol H(2) m(-2) h(-1) for 4,000 h with nongrowing Rhodopseudomonas palustris, a purple nonsulfur photosynthetic bacterium. This adhesive, flexible, nanoporous Rps. palustris latex coating produced 8.24 +/- 0.03 mol H(2) m(-2) in an argon atmosphere when supplied with acetate and light. A simple low-pressure hydrogen production and trapping system was tested using a 100 cm(2) coating. Rps. palustris CGA009 was combined in a bilayer coating with a carotenoid-less mutant of Rps. palustris (CrtI(-)) deficient in peripheral light harvesting (LH2) function. Cryogenic field emission gun scanning electron microscopy (cryo-FEG-SEM) and high-pressure freezing were used to visualize the microstructure of hydrated coatings. A light interaction and reactivity model was evaluated to predict optimal coating thickness for light absorption using the Kubelka-Munk theory (KMT) of reflectance and absorptance. A two-flux model predicted light saturation thickness with good agreement to observed H(2) evolution rate. A combined materials and modeling approach could be used for guiding cellular engineering of light trapping and reactivity to enhance overall photosynthetic efficiency per meter square of sunlight incident on photocatalysts.

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A model system for increasing the intensity of whole-cell biocatalysis: Investigation of the rate of oxidation ofD-sorbitol toL-sorbose by thin bi-layer latex coatings of non-growingGluconobacter oxydans

Fidaleo

Charaniya

Solheid

et al. 2006

Biotechnol. Bioeng.

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We developed a novel <50-microm thick nano-porous bi-layer latex coating for preserving Gluconobacter oxydans, a strict aerobe, as a whole cell biocatalyst. G. oxydans was entrapped in an acrylate/vinyl acetate co-polymer matrix (T (g) approximately 10 degrees C) and cast into 12.7-mm diameter patch coatings (cellcoat) containing approximately 10(9) CFU covered by a nano-porous topcoat. The oxidation of D-sorbitol to L-sorbose was used to investigate the coating catalytic properties. Intrinsic kinetics was studied in microbioreactors using a pH 6.0 D-sorbitol, phosphate, pyruvate (SPP) non-growth medium at 30 degrees C, and the Michaelis-Menten constants determined. By using a diffusion cell, cellcoat and topcoat diffusivities, optimized by arresting polymer particle coalescence by glycerol and/or sucrose addition, were determined. Cryo-FESEM images revealed a two-layer structure with G. oxydans surrounded by <40-nm pores. Viable cell density, cell leakage, and oxidation kinetics in SPP medium for >150 h were investigated. Even though the coatings were optimized for permeability, approximately 50% of G. oxydans viability was lost during cellcoat drying and further reduction was observed as the topcoat was added. High reaction rates per unit volume of coating (80-100 g/L x h) were observed which agreed with predictions of a diffusion-reaction model using parameters estimated by independent experiments. Cellcoat effectiveness factors of 0.22-0.49 were observed which are 20-fold greater than any previously reported for this G. oxydans oxidation. These nano-structured coatings and the possibility of improving their ability to preserve G. oxydans viability may be useful for engineering highly reactive adhesive coatings for multi-phase micro-channel and membrane bioreactors to dramatically increase the intensity of whole-cell oxidations.

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Microstructure Evolution in Polymer Latex Coatings for Whole-Cell Biocatalyst Application

Cited by 24 publications

References 6 publications

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Progress toward a biomimetic leaf: 4,000 h of hydrogen production by coating‐stabilized nongrowing photosynthetic Rhodopseudomonas palustris

A model system for increasing the intensity of whole-cell biocatalysis: Investigation of the rate of oxidation ofD-sorbitol toL-sorbose by thin bi-layer latex coatings of non-growingGluconobacter oxydans

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