University of North Florida
Browse the Citations
-OR-

Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

View Stuart Chalk's profile on LinkedIn

Applied Microbiology and Biotechnology

  • Publisher: Springer
  • FAD Code: AMBT
  • CODEN: AMBIDG
  • ISSN: 0175-7598
  • Abbreviation: Appl. Microbiol. Biotechnol.
  • DOI Prefix: 10.1007/s00253-
  • Language: English
  • Comments: Fulltext from 1975 V1

Citations 16

"Development Of Enzyme Flow Calorimeter System For Monitoring Of Microbial Glycerol Conversion"
Appl. Microbiol. Biotechnol. 2006 Volume 72, Issue 6 Pages 1170-1175
Vladimír Štefuca, Igor Voštiar, Jana Šefčovičová, Jaroslav Katrlík, Vladimír Mastihuba, Mária Greifová and Peter Gemeiner

Abstract: Glycerokinase from Cellulomonas sp. was used to develop biosensor based on flow calorimetry for quantitative analysis of glycerol during bioconversion process. An automatic flow injection analysis device with the glycerol biosensor was built and tested during growth on glycerol of 1,3-propanediol-producing bacteria. The biosensor exhibited an extreme storage and operational stability enabling us to use it for more than 2 years without significant loss of sensitivity. No interference with 1,3-propanediol and fermentation medium was observed. The linear range of glycerol concentration up to 70 mM was extended by developed automatic dilution technique with the aim of automatic online monitoring of microbial process. The analytical system was able to monitor the bioconversion process in a fully automatic way during the whole run with sampling frequency of one sample per 10 min. © 2006 Springer-Verlag.

"Micro Total Analysis System (µ-TAS) In Biotechnology"
Appl. Microbiol. Biotechnol. 2004 Volume 64, Issue 3 Pages 289-299
S. J. Lee and S. Y. Lee

Abstract: Nanobiotechnology raises fascinating possibilities for new analytical assays in various fields such as bioelectronic assembly, biomechanics and sampling techniques, as well as in chips or micromachined devices. Recently, nanotechnology has greatly impacted biotechnological research with its potential applications in smart devices that can operate at the level of molecular manipulation. Micro total analysis system (µ-TAS) offers the potential for highly efficient, simultaneous analysis of a large number of biologically important molecules in genomic, proteomic and metabolic studies. This review aims to describe the present state-of-the-art of microsystems for use in biotechnological research, medicine and diagnostics.

"Optimization Of The Extracellular Production Of A Bacterial Phytase With Escherichia Coli By Using Different Fed-batch Fermentation Strategies"
Appl. Microbiol. Biotechnol. 2003 Volume 61, Issue 5-6 Pages 456-462
S. Kleist, G. Miksch, B. Hitzmann, M. Arndt, K. Friehs, E. Flaschel

Abstract: The extracellular production of Escherichia coli phytase was studied in fed-batch fermentations. Two different feeding strategies were compared: control by keeping the glucose concentration constant, and control by keeping a low constant oxygen level in the medium. For the feeding control based on glucose concentration, a recently developed rapid glucose controlling system was tested for the first time in bacterial cultivations and used to establish the fermentative production of extracellular phytase with E. coli. High activity levels (120 U ml-;1) at short cultivation times (14 h) were obtained. Even higher activity levels-albeit at longer cultivation times-were reached by applying a feeding control, the main characteristic of which was a constant low oxygen concentration. The optimum oxygen level for the production of phytase was in the range of 5-10% saturation.

"A Calorimetrically Based Method To Convert Toxic Compounds Into Poly-3-hydroxybutyrate And To Determine The Efficiency And Velocity Of Conversion"
Appl. Microbiol. Biotechnol. 2001 Volume 55, Issue 2 Pages 234-238
T. Maskow, W. Babel

Abstract: A fed-batch method for converting toxic substrates into poly-3-hydroxybutyrate is presented. The method involves a series of batch-growth processes, regulated by adding small amounts of carbon substrate, during the course of which the concentration of the nitrogen source decreases and controls the distribution of the substrate-carbon assimilated. The addition of carbon substrate is controlled, and the small changes that occur in the growth pattern are interpreted using high-resolution reaction calorimetry. The method was tested with Ralstonia eutropha DSM 4058 growing on phenol, and Variovorax paradoxus DSM 4065 growing on sodium benzoate. The maximum carbon conversion efficiencies (CCEs) obtained, 23% and 27% respectively, were compared with the theoretically possible values.

"Fungal Pyranose Oxidases: Occurrence, Properties And Biotechnical Applications In Carbohydrate Chemistry"
Appl. Microbiol. Biotechnol. 2000 Volume 54, Issue 6 Pages 727-740
F. Giffhorn

Abstract: Pyranose oxidases are widespread among lignin-degrading white rot fungi and are localized in the hyphal periplasmic space. They are relatively large flavoproteins which oxidize a number of common monosaccharides on carbon-2 in the presence of oxygen to yield the corresponding 2-keto sugars and hydrogen peroxide. The preferred substrate of pyranose oxidases is D-glucose which is converted to 2-keto-D-glucose. While hydrogen peroxide is a cosubstrate in ligninolytic reactions, 2-keto-D-glucose is the key intermediate of a secondary metabolic pathway leading to the antibiotic cortalcerone. The finding that 2-keto-D-glucose can serve as an intermediate in an industrial process for the conversion of D-glucose into D-fructose has stimulated research on the use of pyranose oxidases in biotechnical applications. Unique catalytic potentials of pyranose oxidases have been discovered which make these enzymes efficient tools in carbohydrate chemistry. Converting common sugars and sugar derivatives with pyranose oxidases provides a pool of sugar-derived intermediates for the synthesis of a variety of rare sugars, fine chemicals and drugs.

"Monitoring Of Low Concentrations Of Glucose In Fermentation Broth"
Appl. Microbiol. Biotechnol. 1999 Volume 52, Issue 4 Pages 502-507
M. P. Nandakumar, A. Sapre, A. Lali, B. Mattiasson

Abstract: A highly sensitive glucose sensor, operating in flow injection analysis (FIA) mode, was developed for the detection of glucose in fermentation broth. The assay system is based upon the post-column reaction of the peroxide formed in the glucose-oxidase-catalyzed reaction and subsequent spectrophotometric detection of the colored product formed. The sensor system was characterized and calibrated using standard solutions, and later used for quantification of glucose in fermentation media. Two types of enzyme column were used: one operated in packed-bed mode and the other in expanded-bed mode. Both columns were integrated into a FIA system and were found to give good analytical results. Glucose concentrations as low as 0.1 mg/l and 5 mg/l could be detected in packed-and expanded-bed modes respectively. Glucose concentrations were measured during typical fed-batch fermentation conditions in this system, and the results are presented.
Glucose

"Immunoaffinity Layering Of Enzymes -Stabilization And Use In Flow Injection Analysis Of Glucose And Hydrogen Peroxide"
Appl. Microbiol. Biotechnol. 1999 Volume 52, Issue 3 Pages 373-379
M. Farooqi, P. Sosnitza, M. Saleemuddin, R. Ulber, T. Scheper

Abstract: A general procedure for the high yield immobilization of enzymes with the help of specific anti-enzyme antibodies is described. Polyclonal antibodies were raised against Aspergillus niger glucose oxidase and horseradish peroxidase in rabbits and the gamma globulin (IgG) fraction from the immune sera isolated by ammonium sulfate fractionation followed by ion-exchange chromatography. Immobilization of glucose oxidase and horseradish peroxidase was achieved by initially binding the enzymes to a Sepharose matrix coupled with IgG isolated from anti-(glucose oxidase) and anti-(horseradish peroxidase) sera, respectively. This was followed by alternate incubation with the IgG and the enzyme to assemble layers of enzyme and antibody on the support. The immunoaffinity-layered preparations obtained thus were highly active and, after six binding cycles, the amount of enzyme immobilized could be raised about 25 times over that bound initially. It was also possible to assemble layers of glucose oxidase using unfractionated antiserum in place of the IgG. The bioaffinity-layered preparations of glucose oxidase and horseradish peroxidase exhibited good enzyme activities and improved resistance to heat-induced inactivation. The sensitivity of a flow injection analysis system for measuring glucose and hydrogen peroxide could be remarkably improved using immunoaffinity-layered glucose oxidase and horseradish peroxidase. For the detection of glucose, a Clark-type oxygen electrode, constructed as a small flow-through cell integrated with a cartridge bearing immunoaffinity-layered glucose oxidase was employed. The hydrogen peroxide concentration was analyzed spectrophotometrically using a flow-through cell and the layered horseradish peroxidase packed into a cartridge. The immunoaffinity-layered enzymes could be conveniently solubilized at acid pH and fresh enzyme loaded onto the support. Immunoaffinity-layered glucose oxidase was successfully used for the online monitoring of the glucose concentration during the cultivation of Streptomyces cerevisiae.
Glucose

"On-line Enzyme Activity Determination Using The Stopped-flow Technique: Application To Laccase Activity In Pulp Mill Waste-water Treatment"
Appl. Microbiol. Biotechnol. 1997 Volume 48, Issue 2 Pages 168-173
X. Font, G. Caminal, X. Gabarrell, J. Lafuente, M. T. Vicent

Abstract: An automated system for on-line measurement of enzyme activity is proposed. The system uses a flow injection manifold in the stopped-flow mode to measure initial reaction rates. The time during which the flow is halted is selected in such a way as to optimise the enzyme/substrate ratio for the correct determination of activity values. The proposed system was used to determine the activity of laccase produced by the fungus Trametes versicolor immobilized on nylon in a fixed-bed reactor used for treating pulp mill waste water.

"High Volumetric Yields Of Functional Dimeric Miniantibodies In Escherichia Coli, Using An Optimized Expression Vector And High-cell-density Fermentation Under Non-limited Growth Conditions"
Appl. Microbiol. Biotechnol. 1996 Volume 46, Issue 5-6 Pages 524-532
U. Horn, W. Strittmatter, A. Krebber, U. Knüpfer, M. Kujau, R. Wenderoth, K. Müller, S. Matzku, A. Plückthun, D. Riesenberg

Abstract: Functional bivalent miniantibodies, directed against the epidermal growth factor receptor, accumulated to more than 3 gl^m1 in high-cell-density cultures of Escherichia coli RV308(pHKK) on a pilot scale. The miniantibodies consist of scFv fragments with a C-termi-nal hinge followed by a helix-turn-helix motif, which homodimerizes in vivo. The improved expression vector pHKK is characterized by the hok/sok suicide system, improving plasmid maintenance, and the inducible lac p/o promoter system with the very strong T7g10 Shine-Dalgarno sequence. The expression unit is flanked by terminators. The prototrophic RV308 cells were cultivated in glucose mineral salt medium and reached a cell density of 145 g dry biomass l^m1 after 33 h. After induction, growth continued almost unchanged for a further 4 h with concomitant miniantibody formation. In the fed-batch phase, the concentration of glucose was kept almost constant at the physiological level of approximately 1.5 g l^m1, using on-line flow injection analysis for control. Surprisingly, E. coli RV308(pHKK) did not accumulate significant amounts of the metabolic by-product acetate under these unlimited aerobic growth conditions.

"Monitoring And Control Of Biotechnological Production Processes By Bio-FET-FIA-sensors"
Appl. Microbiol. Biotechnol. 1991 Volume 36, Issue 2 Pages 167-172
U. Brand, L. Brandes, V. Koch, T. Kullik, B. Reinhardt, F. Rüther, T. Scheper, K. Schügerl, S. Wang, X. Wu, R. Ferretti, S. Prasad and D. Wilhelm

Abstract: Single and multisensor field effect transistors (FET) with a pH-sensitive Si/SiO2/Si3N4/Ta2O5-gate and reference electrode (for single sensor) were developed and used for manufacturing the following biological (Bio)-FETs: for glucose analysis, glucose oxidase-FET (GOD-FET); for urea analysis, urease-FET; and for cephalosporin C analysis, cephalosporinase-FET. The GOD-FETs were integrated into flow injection analysis (FIA) of the Eppendorf variables analyzer. (EVA) system and used for monitoring the glucose concentration in microbial cultivation and production processes with recombinant Escherichia coli K12 MF, recombinant E. coli JM103, Saccharomyces cerevisiae H620, and Candida boidinii. Urease-FET-FIA was used to monitor the urea concentration in a simulated cultivation of Cephalosporium acremonium and urease-FET-FIA and GOD-FET-FIA for the monitoring of urea and glucose concentrations in simulated S. cerevisiae cultivations.

"Production Of Alkaline Protease With Bacillus Licheniformis In A Controlled Fed-batch Process"
Appl. Microbiol. Biotechnol. 1991 Volume 35, Issue 6 Pages 720-724
Ulrich Eberhard Giesecke, Gabriele Bierbaum, Heinz Rudde, Uwe Spohn and Christian Wandrey

Abstract: A production method for alkaline serine protease with Bacillus licheniformis in a synthetic medium was developed. Employing closed-loop control of oxygen, nitrogen and carbon source the pO2 was held at 5%, the ammonium concentration kept below 1 mM and the glycerol concentration was maintained between 20 and 100 mM. Protease production was monitored by flow injection analysis. Thus, in a fed-batch procedure production could be increased 4.6-fold in comparison to an uncontrolled batch process.

"On-line Monitoring Of Pullulanase Production During Continuous Culture Of Clostridium Thermosulfurogenes"
Appl. Microbiol. Biotechnol. 1991 Volume 35, Issue 4 Pages 471-476
Ruth Freitag, Thomas Scheper, Andreas Spreinat and Garo Antranikian

Abstract: An automated turbidimetric immunoassay for pullulanase from Clostridium thermosulfurogenes was developed for on-line bioprocess monitoring. Measurements are based on the turbidity caused by specific aggregation between pullulanase molecules present in the cultivation medium and antibodies against these enzymes. The time for one assay cycle is 3.0 min. Pullulanase concentrations between 10 units (U)/l and 1000 U/l could be measured. Standard deviations of less than 2% were found. The analysis system could be successfully employed for on-line product monitoring during a 240-h cultivation of C. thermosulfurogenes. An average correlation factor of 0.975 was obtained for the pullulanase data from on-line turbidimetric and the off-line reference assay, demonstrating the accuracy of this on-line method.

"Investigations Of Cephalosporin C Production In An Airlift Tower Loop Reactor"
Appl. Microbiol. Biotechnol. 1989 Volume 30, Issue 1 Pages 26-33
T. Bayer, W. Zhou, K. Holzhauer and K. Schügerl

Abstract: Cephalosporin C was produced by Cephalosporium acremonium in a 60 l airlift loop reactor on complex medium (with 30 kg/m3 peanut flour) in fed-batch operation. A final product concentration of 5 kg/m3 and a maximum productivity of 45 g/m3 h were attained. On-line analysis was used to determine ammonia, methionine, phosphate, reducing sugar and cephalosporin C by an autoanalyzer., glucose by a flow injection analyzer. and cephalosporin C, penicillin N, deacetoxycephalosporin C, deacetylce-phalosporin C and methionine by HPLC. The volumetric productivity of the stirred tank reactor was higher than that of the airlift reactor because of differences in cell concentration. Specific productivities in relative to cell mass were similar in the two reactors. The substrate yield coefficient in the airlift reactor was twice that in the stirred tank reactor.

"Measurement Of Ammonium Utilization By Escherichia Coli Under Ammonium Limitation By Means Of An Ammonia-sensitive Semiconductor Device"
Appl. Microbiol. Biotechnol. 1988 Volume 29, Issue 1-3 Pages 269-274
E. G. Hörnsten , L. Nilsson, F. Winquist, H. Elwing and I. Lundström

Abstract: The concentration of ammonium in the medium of anEscherichia coli fermentation during ammonium limitation was followed by means of a newly developed semiconductor device, the ammonia gas-sensitive thin platinum metal oxide semiconductor structure (Pt-TMOS). It has been shown that the ammonia sensitivity of the sensor was sufficient for determination of ammonium concentrations at growth limitation due to ammonium depletion. Furthermore, the corresponding ATP concentration and dissolved oxygen tension during the progress of the fermentation was followed.

"Hydrogen Peroxide As An Oxygen Source For Immobilized Gluconobacter Oxydans Converting Glycerol To Dihydroxyacetone"
Appl. Microbiol. Biotechnol. 1985 Volume 22, Issue 6 Pages 383-388
Olle Holst , Hans Lundbäck and Bo Mattiasson

Abstract: A flow injection analysis (FIA) system with amperometric detection was developed for measuring hydrogen peroxide which was used as an oxygen source for immobilized cells. A constant concentration of peroxide in the reactor was maintained by processing the analytical signal in a computer programmed as a PI-regulator. The concentration of dissolved oxygen was followed using a commercial Clark-electrode. The simultaneous measurements of hydrogen peroxide and dissolved oxygen are discussed with respect to process control. Conversion of glycerol to dihydroxyacetone by Gluconobacter oxydans immobilized in calcium alginate was used as a model system. Initial specific productivity increased with increasing hydrogen peroxide concentration. However, decreases in viable counts, enzymatic activities and overall productivities were noted. Various techniques for improving operational stability are discussed.
Hydrogen peroxide Fermentation broth Amperometry Optimization Process control

"Monitoring And Control Of Enzymic Sucrose Hydrolysis Using On-line Biosensors"
Appl. Microbiol. Biotechnol. 1985 Volume 21, Issue 3-4 Pages 135-142
C. F. Mandenius , L. Bülow, B. Danielsson and K. Mosbach

Abstract: Previously reported flow microcalorimeter devices for enzymatic reaction heat measurement, enzyme thermistors, have here been extended with systems for on-line sample treatment. Glucose analysis was performed by intermittent flow injections of 50 µL samples through such an enzyme thermistor device containing immobilized glucose oxidase and catalase. Sucroce analysis was performed by allowing diluted samples to continuously pass through an additional enzyme thermistor containing immobilized invertase. The reaction heats were recorded as temperature changes in the order of 10^-50 m°C for concentrations of 0.05-0.30 M glucose or sucrose present in the original non-diluted samples. The performance of this system was investigated by its ability to follow concentration changes obtained from a gradient mixer. The system was applied to monitoring and controlling the hydrolysis of sucrose to glucose and fructose in a plug-flow reactor with immobilized invertase. The reactor was continuously fed by a flow of scurose of up to 0.3 M (100 g/l). Glucose and remaining sucrose were monitored in the effluent of the column. By using flow rate controlled feed pumps for sucrose and diluent the influent concentration of sucrose was varied while the overall flow rate remained constant.