Search our Database of Scientific Publications and Authors

I’m looking for a

    99 results match your criteria Biochemical Engineering Journal [Journal]

    1 OF 2

    Aggregation of Culture Expanded Human Mesenchymal Stem Cells in Microcarrier-based Bioreactor.
    Biochem Eng J 2018 Mar 13;131:39-46. Epub 2017 Dec 13.
    Department of Chemical and Biomedical Engineering, Florida State University, 2525 Pottsdamer St., Tallahassee, FL 32310, USA.
    Three-dimensional aggregation of human mesenchymal stem cells (hMSCs) has been used to enhance their therapeutic properties but current fabrication protocols depend on laboratory methods and are not scalable. In this study, we developed thermal responsive poly(N-isopropylacrylamide) grafted microcarriers (PNIPAM-MCs), which supported expansion and thermal detachment of hMSCs at reduced temperature (23.0 °C). Read More

    Comparative Proteomic Analysis of Three Chinese Hamster Ovary (CHO) Host Cells.
    Biochem Eng J 2017 Aug 15;124:122-129. Epub 2017 May 15.
    Department of Biomedical Engineering, University of Alabama at Birmingham (UAB), 1670 University Blvd, Birmingham, AL 35233, USA.
    Chinese hamster ovary (CHO) cells have been widely used to express heterologous genes and produce therapeutic proteins in biopharmaceutical industry. Different CHO host cells have distinct cell growth rates and protein expression characteristics. In this study, the expression of about 1,307 host proteins in three sublines, i. Read More

    Pneumatic hydrodynamics influence transplastomic protein yields and biological responses during shoot regeneration of callus: Implications for bioprocess routes to plant-made biopharmaceuticals.
    Biochem Eng J 2017 Jan;117(Pt B):73-81
    Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
    Transplastomic plants are capable of high-yield production of recombinant biopharmaceutical proteins. Plant tissue culture combines advantages of agricultural cultivation with the bioprocess consistency associated with suspension culture. Overexpression of recombinant proteins through regeneration of transplastomic shoots from callus tissue in RITA temporary immersion bioreactors has been previously demonstrated. Read More

    From by-product to valuable components: Efficient enzymatic conversion of lactose in whey using β-galactosidase from .
    Biochem Eng J 2016 Dec;116:45-53
    Food Biotechnology Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
    β-Galactosidase from was overexpressed in a food-grade organism, WCFS1. Laboratory cultivations yielded 11,000 U of β-galactosidase activity per liter of culture corresponding to approximately 170 mg of enzyme. Crude cell-free enzyme extracts obtained by cell disruption and subsequent removal of cell debris showed high stability and were used for conversion of lactose in whey permeate. Read More

    Megakaryocyte Polyploidization and Proplatelet Formation in Low-Attachment Conditions.
    Biochem Eng J 2016 Jul;111:24-33
    Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL.
    -derived platelets (PLTs), which could provide an alternative source of PLTs for patient transfusions, are formed from polyploid megakaryocytes (MKs) that extend long cytoplasmic projections, termed proplatelets (proPLTs). In this study, we compared polyploidization and proPLT formation (PPF) of MKs cultured on surfaces that either promote or inhibit protein adsorption and subsequent cell adhesion. A megakaryoblastic cell line exhibited increased polyploidization and arrested PPF on a low-attachment surface. Read More

    Modelling of amorphous cellulose depolymerisation by cellulases, parametric studies and optimisation.
    Biochem Eng J 2016 Jan;105(Pt B):455-472
    Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, England, UK.
    Improved understanding of heterogeneous cellulose hydrolysis by cellulases is the basis for optimising enzymatic catalysis-based cellulosic biorefineries. A detailed mechanistic model is developed to describe the dynamic adsorption/desorption and synergistic chain-end scissions of cellulases (endoglucanase, exoglucanase, and β-glucosidase) upon amorphous cellulose. The model can predict evolutions of the chain lengths of insoluble cellulose polymers and production of soluble sugars during hydrolysis. Read More

    Good's buffers as novel phase-forming components of ionic-liquid-based aqueous biphasic systems.
    Biochem Eng J 2015 Sep;101:142-149
    CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
    Aiming at the development of self-buffering and benign extraction/separation processes, this work reports a novel class of aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and organic biological buffers (Good's buffers, GBs). A large array of ILs and GBs was investigated, revealing than only the more hydrophobic and fluorinated ILs are able to form ABS. For these systems, the phase diagrams, tie-lines, tie-line lengths, and critical points were determined at 25 °C. Read More

    Suppressing mutation-induced protein aggregation in mammalian cells by mutating residues significantly displaced upon the original mutation.
    Biochem Eng J 2014 Oct;91:196-203
    Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904-4741, United States ; School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea.
    Mutations introduced to wild-type proteins naturally, or intentionally via protein engineering, often lead to protein aggregation. In particular, protein aggregation within mammalian cells has significant implications in the disease pathology and biologics production; making protein aggregation modulation within mammalian cells a very important engineering topic. Previously, we showed that the semi-rational design approach can be used to reduce the intracellular aggregation of a protein by recovering the conformational stability that was lowered by the mutation. Read More

    Engineered drug-protein nanoparticle complexes for folate receptor targeting.
    Biochem Eng J 2014 Aug;89:33-41
    Department of Chemical Engineering and Materials Science University of California, 916 Engineering Tower, Irvine, CA 92697-2575, USA.
    Nanomaterials that are used in therapeutic applications need a high degree of uniformity and functionality which can be difficult to attain. One strategy for fabrication is to utilize the biological precision afforded by recombinant synthesis. Through protein engineering, we have produced ~27-nm dodecahedral protein nanoparticles using the thermostable E2 subunit of pyruvate dehydrogenase as a scaffold and added optical imaging, drug delivery, and tumor targeting capabilities. Read More

    Biofabrication of ZnS:Mn luminescent nanocrystals using histidine, hexahistidine, and His-tagged proteins: a comparison study.
    Biochem Eng J 2014 Aug;89:28-32
    Department of Chemical Engineering, Box 351750, University of Washington, Seattle, WA 98195-1750, United States.
    The ubiquitous hexahistidine purification tag has been used to conjugate proteins to the shell of CdSe:ZnS quantum dots (QDs) due to its affinity for surface-exposed Zn ions but little attention has been paid to the potential of His-tagged proteins for mineralizing luminescent ZnS nanocrystals. Here, we compare the ability of free histidine, a His tag peptide, His-tagged thioredoxin (TrxA, a monomeric protein), and N- and C-terminally His-tagged versions of Hsp31 (a homodimeric protein) to support the synthesis of Mn-doped ZnS nanocrystals from aqueous precursors under mild conditions of pH (8.2) and temperature (37°C). Read More

    The effects of protein solubility on the RNA Integrity Number (RIN) for recombinant .
    Biochem Eng J 2013 Oct;79:129-135
    Department of Bioengineering, Clemson University.
    High quality, intact messenger RNA (mRNA) is required for DNA microarray and reverse transcriptase polymerase chain reaction analysis and is generally obtained from total RNA isolations. The most widely recognized measure of RNA integrity is the RNA Integrity Number (RIN) obtained from the Agilent Bioanalyzer, as it provides sizing, quantification, and quality control measures. This work describes comparisons of the RIN values obtained for recombinant . Read More

    Reproducible culture and differentiation of mouse embryonic stem cells using an automated microwell platform.
    Biochem Eng J 2013 Aug;77(100):246-257
    The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
    The use of embryonic stem cells (ESCs) and their progeny in high throughput drug discovery and regenerative medicine will require production at scale of well characterized cells at an appropriate level of purity. The adoption of automated bioprocessing techniques offers the possibility to overcome the lack of consistency and high failure rates seen with current manual protocols. To build the case for increased use of automation this work addresses the key question: "can an automated system match the quality of a highly skilled and experienced person working manually?" To answer this we first describe an integrated automation platform designed for the 'hands-free' culture and differentiation of ESCs in microwell formats. Read More

    Elastomeric Recombinant Protein-based Biomaterials.
    Biochem Eng J 2013 Aug;77:110-118
    Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, 02139, USA ; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA ; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts, 02139, USA.
    Elastomeric protein-based biomaterials, produced from elastin derivatives, are widely investigated as promising tissue engineering scaffolds due to their remarkable properties including substantial extensibility, long-term stability, self-assembly, high resilience upon stretching, low energy loss, and excellent biological activity. These elastomers are processed from different sources of soluble elastin such as animal-derived soluble elastin, recombinant human tropoelastin, and elastin-like polypeptides into various forms including three dimensional (3D) porous hydrogels, elastomeric films, and fibrous electrospun scaffolds. Elastin-based biomaterials have shown great potential for the engineering of elastic tissues such as skin, lung and vasculature. Read More

    Paclitaxel uptake and transport in Taxus cell suspension cultures.
    Biochem Eng J 2012 Apr 29;63:50-56. Epub 2012 Jan 29.
    University of Massachusetts-Amherst, Department of Chemical Engineering, 686 North Pleasant Street, 159 Goessmann Laboratory, Amherst, MA 01003.
    The transport of paclitaxel in Taxus canadensis suspension cultures was studied with a fluorescence analogue of paclitaxel (Flutax-2(®)) in combination with flow cytometry detection. Experiments were carried out using both isolated protoplasts and aggregated suspension cell cultures. Flutax-2(®) was shown to be greater than 90% stable in Taxus suspension cultures over the required incubation time (24 hours). Read More

    Self-interaction chromatography of proteins on a microfluidic monolith.
    Biochem Eng J 2011 Jan;53(2):216-22
    Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA.
    A novel miniaturized system has been developed for measuring protein-protein interactions in solution with high efficiency and speed, and minimal use of protein. A chromatographic monolith synthesized in a capillary is used in the method to make interaction measurements by self-interaction chromatography (SIC) in a manner that, compared to column methods, is more efficient as well as more readily practicable even if only small amounts of protein are available. The microfluidic monolith requires much less protein for both column synthesis and the chromatographic measurements than a conventional SIC system, and in addition offers improved mass transfer and hence higher chromatographic efficiency than for previous SIC miniaturization systems. Read More

    Development of Scalable Culture Systems for Human Embryonic Stem Cells.
    Biochem Eng J 2010 Feb;48(3):378
    Department of Chemical and Biological Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706.
    The use of human pluripotent stem cells, including embryonic and induced pluripotent stem cells, in therapeutic applications will require the development of robust, scalable culture technologies for undifferentiated cells. Advances made in large-scale cultures of other mammalian cells will facilitate expansion of undifferentiated human embryonic stem cells (hESCs), but challenges specific to hESCs will also have to be addressed, including development of defined, humanized culture media and substrates, monitoring spontaneous differentiation and heterogeneity in the cultures, and maintaining karyotypic integrity in the cells. This review will describe our current understanding of environmental factors that regulate hESC self-renewal and efforts to provide these cues in various scalable bioreactor culture systems. Read More

    Cholesterol Supplementation During Production Increases the Infectivity of Retroviral and Lentiviral Vectors Pseudotyped with the Vesicular Stomatitis Virus Glycoprotein (VSV-G).
    Biochem Eng J 2009 May;44(2-3):199-207
    Department of Chemical and Biological Engineering, Northwestern University, Evanston IL 60208.
    Cholesterol, a major component of plasma membrane lipid rafts, is important for assembly and budding of enveloped viruses, including influenza and HIV-1. Cholesterol depletion impairs virus assembly and infectivity. This study examined the effects of exogenous cholesterol addition (delivered as a complex with methyl beta cyclodextrin) on the production of Molony murine leukemia virus retroviral vector and HIV-1-based lentiviral vector pseudotyped with the vesicular stomatitis virus glycoprotein (VSV-G). Read More

    Dynamics of Positional Enrichment: Theoretical Development and Application to Carbon Labeling in Zymomonas mobilis.
    Biochem Eng J 2008 May;40(1):157-174
    Dept. of Biostatistics, Bioinformatics and Epidemiology. Medical University of South Carolina, Charleston, SC. USA.
    Positional enrichment analysis has become an important technique for assessing detailed flux distributions and the fates of specific atoms in metabolic pathway systems. The typical approach to positional enrichment analysis is performed by supplying specifically labeled substrate to a cell system, letting the system reach steady state, and measuring where label had arrived and accumulated. The data are then evaluated mathematically with the help of a linear stoichiometric flux distribution model. Read More

    A modified method for determination of diffusivities of low molecular substances in non-Newtonian liquids.
    Biochem Eng J 2001 Jul;8(1):83-89
    University of Chemical Technology and Metallurgy, 1756, Sofia, Bulgaria
    A modified method for determination of diffusivities of low molecular substances in non-Newtonian liquids described by the power-law model has been proposed. It is based on the dissolution of Geiss body, with a parameter m=1/3 rotating in an infinite fluid. In this case, the solution of the differential equations of motion and mass transfer is available as an analytical formula for calculating the diffusivity coefficient. Read More

    Carbon sources affect metabolic capacities of Bacillus species for the production of industrial enzymes: theoretical analyses for serine and neutral proteases and alpha-amylase.
    Biochem Eng J 2001 Jul;8(1):61-81
    Department of Chemical Engineering, Middle East Technical University, 06531, Ankara, Turkey
    The metabolic fluxes through the central carbon pathways were calculated for the genus Bacillus separately for the enzymes serine alkaline protease (SAP), neutral protease (NP) and alpha-amylase (AMY) on five carbon sources that have different reduction degrees (gamma), to determine the theoretical ultimate limits of the production capacities of Bacillus species and to predict the selective substrate for the media design. Glucose (gamma=4.0), acetate (gamma=4. Read More

    Biosorption of gold by immobilized fungal biomass.
    Biochem Eng J 2001 Jul;8(1):51-59
    Department of Chemical and Environmental Engineering, National University of Singapore, 119260, Singapore, Singapore
    The characteristics of polyvinyl alcohol (PVA) and calcium alginate as immobilization matrices were examined and compared for the uptake of gold by a fungal biomass. PVA-immobilized biomass showed superior mechanical strength and chemical stability. In addition, PVA beads were also stable under a wider range of pH (1-13). Read More

    Modelling plasmid instability in batch and continuous fermentors.
    Biochem Eng J 2001 Jul;8(1):45-50
    Department of Chemical Engineering and Petroleum Engineering, 2500 University Drive NW, AB, T2N 1N4, Calgary, Canada
    The probability of complete loss of plasmid material from plasmid bearing cells undergoing active growth has been modelled and incorporated into predictions for the dynamic concentrations of plasmid bearing cells in both batch and continuous flow, stirred tank bioreactors. The new model is based on an extension of the well-used model of Imanaka and Aiba [Ann. New York Acad. Read More

    Whole cell biocatalyst for biodiesel fuel production utilizing Rhizopus oryzae cells immobilized within biomass support particles.
    Biochem Eng J 2001 Jul;8(1):39-43
    Fujikin Incorporated, 90 Sinke-Higashi, Higashi- 577-0026, Osaka, Japan
    As part of a research program aimed at producing biodiesel fuel from plant oils enzymatically cells of Rhizopus oryzae (R. oryzae) IFO4697 (with a 1,3-positional specificity lipase) immobilized within biomass support particles (BSPs) were investigated for the methanolysis of soybean oil. The R. Read More

    Chemometric optimisation of parameters for biocatalytic reduction of copper ion by a crude enzyme lysate of Saccharomyces cerevisiae grown under catabolic repression conditions.
    Biochem Eng J 2001 Jul;8(1):31-37
    Department of Chemical Engineering, Anna University, Chennai, India
    The capacity of the microbes to reduce the metal has been demonstrated. The immobilised induced microbes with toxic chemical CuCl(2) was used to reduce the Cu ions as elemental metal and by using the response surface methodology the parameters such as the inducer concentration, the time of inducer addition which are concerned with the growth and formation of specific enzymes and the initial substrate concentration, initial pH of the substrate solution and the time of reaction which are concerned with the biocatalytic reduction of the metal ions were optimised for maximum reduction. The elemental copper reduced and removed experimentally from its ionic state at the optimum conditions was 54. Read More

    Scale-up of biotransformation process in stirred tank reactor using dual impeller bioreactor.
    Biochem Eng J 2001 Jul;8(1):19-29
    Department of Chemical Technology, Food and Fermentation Technology Division, University of Mumbai (UDCT), Matunga, 400 019, Mumbai, India
    The gas-liquid mass transfer coefficient K(L)a in the fermenter is a strong function of mode of energy dissipation and physico-chemical properties of the liquid media. A combination of disc turbine (DT) and pitched blade turbine down flow (PTD) impellers has been tested in laboratory bioreactor for gas hold-up and gas-liquid mass transfer performance for the growth and biotransformation medium for an yeast isolate VS1 capable of biotransforming benzaldehyde to L-phenyl acetyl carbinol (L-PAC) and compared with those in water.Correlations have been developed for the prediction of the fractional gas hold-up and gas-liquid mass transfer coefficient for the above media. Read More

    Removal of mixtures of acetaldehyde and propionaldehyde from waste gas in packed column with immobilized activated sludge gel beads.
    Biochem Eng J 2001 Jul;8(1):9-18
    Department of Applied Chemistry and Chemical Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, 755-8611, Yamaguchi, Japan
    The removal of mixed acetaldehyde and propionaldehyde as a model of the binary contaminants in waste gas was studied in the packed column containing the immobilized activated sludge gel beads together with the hollow plastic balls developed for the removal of a single aldehyde in the previous work. The rate of each aldehyde biodegradation by the gel beads in the aldehydes mixture was expressed by the Michaelis-Menten type rate equation with an inhibitory term due to the other coexistent aldehyde. The kinetic parameters involved were found to be the same as those determined previously for biodegradation of a single aldehyde. Read More

    Kinetic analysis of disruption of excess activated sludge by Dyno Mill and characteristics of protein release for recovery of useful materials.
    Biochem Eng J 2001 Jul;8(1):1-7
    Department of Chemical Engineering, Division of Material Science and Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, 240-8501, Yokohama, Japan
    Solubilization of excess sludge (ES) cultivated in a laboratory and that obtained from real wastewater treatment plants by continuous Dyno Mill disruption were studied for the purpose of effective reuse of ES. The total soluble protein concentration released during the ES disruption was found to be closely dependent upon the released protease activity, which suggests the possibility of the enzyme recovery as one of the ES reuse methods. The operating parameters of Dyno Mill significantly affected the ES solubilization. Read More

    Parallel substrate feeding and pH-control in shaking-flasks.
    Biochem Eng J 2001 Mar;7(2):163-170
    Institute of Biochemical Engineering, Munich University of Technology, Boltzmannstr. 15, 85748, Garching, Germany
    An intermittent feeding system for shaking-flasks was developed to close the gap between batch operated shaking-flasks and fed-batch operated as well as pH-controlled stirred tank reactors. A precise syringe pump was connected via a substrate distribution system to individual 2/2-way miniature valves, one for each of up to 16 shaking-flask. The shaking-flasks were equipped with pH-probes. Read More

    Device for sterile online measurement of the oxygen transfer rate in shaking flasks.
    Biochem Eng J 2001 Mar;7(2):157-162
    Department of Biochemical Engineering, Aachen University of Technology, Worringerweg 1, D-52056, Aachen, Germany
    The oxygen transfer rate (OTR) is the most suitable measurable parameter to quantify the physiological state of a culture of aerobic microorganisms since most metabolic activities depend on oxygen consumption. Online measurement of the oxygen transfer rate in stirred bioreactors is state of the art although technically difficult. However, the online determination of the oxygen transfer rate in shaking bioreactors under sterile conditions has not been possible until recently. Read More

    Quantitative measurements of mixing intensity in shake-flasks and stirred tank reactors. Use of the Mixmeter, a mixing process analyzer.
    Biochem Eng J 2001 Mar;7(2):153-156
    Wyeth-Lederle Vaccines, 401 N. Middletown Rd., 10965, Pearl River, NY, USA
    A new mixing probe has been developed which measures the motions of the fluid during mixing as pressure fluctuations and converts the measurements into a mixing signal (MS). The MS is the root mean square (RMS) pressure fluctuation in the 1-64Hz range as determined by a sensitive pressure sensor and a digital signal processor specifically designed for the purpose. The MS is a measure of the actual mixing flow of the fluid rather than a measurement of the input motions or energies into the reactor system (e. Read More

    Performance of a shaking vessel with current pole.
    Biochem Eng J 2001 Mar;7(2):143-151
    Department of Applied Chemistry, Nagoya Institute of Technology, Gokisocho, Showaku, 466-8555, Nagoya, Japan
    To improve solid particle suspensions in liquids in a shaking vessel, a pole was installed at the axis of the shaking vessel, which was referred to as the "current pole". The performance of a shaking vessel with current pole at its central axis was examined experimentally with respect to particle dispersion, power consumption, mixing time and solid-liquid mass transfer coefficient. The current pole improved the particle suspension without an increase in power consumption and reduced the critical circulating frequency for complete suspension. Read More

    Out-of-phase operating conditions, a hitherto unknown phenomenon in shaking bioreactors.
    Biochem Eng J 2001 Mar;7(2):135-141
    Department of Biochemical Engineering, Aachen University of Technology, Sammelbau Biologie, D-52074, Aachen, Germany
    One of the important parameters in characterising fermentations of aerobic microorganisms is the specific power consumption. A new method has been introduced which enables the accurate determination of the power consumption in shaking bioreactors. It is based on torque measurements in the drive and the appropriate compensation of the friction losses. Read More

    Scale-up of filamentous organisms from tubes and shake-flasks into stirred vessels.
    Biochem Eng J 2001 Mar;7(2):127-134
    TerraGen Discovery (UK) Ltd., Slough, UK
    The choice of small-scale fermentation systems contributes significantly to a successful scale-up. Creasing of flasks and the chosen shaker parameters influence the production of secondary metabolites in a strain- and even compound-specific manner. Using actinomycetes and fungi as model organisms the influence of the small-scale fermentation system on the production of various secondary metabolites is described and the effects on screening success and scale-up are considered. Read More

    Development of a shaking bioreactor system for animal cell cultures.
    Biochem Eng J 2001 Mar;7(2):121-125
    Roche Discovery Technologies Department, Hoffmann-La Roche, Inc., 340 Kingsland Street, 07110, Nutley, NJ, USA
    The feasibility of using shake flasks to culture animal cells was evaluated using various sizes of cylindrical shaped vessels as bioreactors. It was found that conditions can be optimized so that hybridoma, Chinese Hamster Ovary cells, and insect cells can be efficiently cultured in the shaking reactors to cell densities comparable to that obtained with stirred-jar bioreactors, and the system is scalable to larger volumes for the production of recombinant proteins or cell mass production in the laboratory. Read More

    Small-scale bioreactor system for process development and optimization.
    Biochem Eng J 2001 Mar;7(2):117-119
    Laboratory of Cellular Biotechnology, Swiss Federal Institute of Technology, Lausanne, Switzerland
    An agitated 12-well microtiter plate system with a working volume of 2ml was investigated for cell culture process development. Agitation assures homogeneity in wells and enhances mass transfer between the gas and the liquid phase, thus improving maximum cell density and pH stability. The pH of the NaHCO(3)-buffered system can be adjusted by altering the carbon dioxide content of the gas phase. Read More

    Effectiveness of orbital shaking for the aeration of suspended bacterial cultures in square-deepwell microtiter plates.
    Biochem Eng J 2001 Mar;7(2):113-115
    Institute of Biotechnology, ETH Hönggerberg, HPT, CH 8093, Zürich, Switzerland
    Growth of heterogeneous culture collections in microtiter plates is advantageous for logistic reasons and also in enabling significant savings in medium costs, labor input and use of equipment during large screening projects. The main hurdles to overcome for aerobic microbial strains are the prevention of cross-contamination and excessive evaporation while assuring sufficient aeration rates. For this purpose we developed a sandwich spongy silicone/cotton wool cover to close the wells of square-deepwell microtiter plates. Read More

    Mass transfer resistance of sterile plugs in shaking bioreactors.
    Biochem Eng J 2001 Mar;7(2):107-112
    Department of Biochemical Engineering, Aachen University of Technology, Worringerweg 1, D-52056, Aachen, Germany
    One of the mass transfer resistances for the gas exchange of shaking flasks is the sterile plug. The gas exchange through the sterile plug is described by an extended model of Henzler and Schedel [Bioprocess Eng. 7 (1991) 123]. Read More

    Characterisation of the gas-liquid mass transfer in shaking bioreactors.
    Biochem Eng J 2001 Mar;7(2):99-106
    Department of Biochemical Engineering, Aachen University of Technology (RWTH), Sammelbau Biologie, D-52074, Aachen, Germany
    The maximum gas-liquid mass transfer capacity of 250ml shaking flasks on orbital shaking machines has been experimentally investigated using the sulphite oxidation method under variation of the shaking frequency, shaking diameter, filling volume and viscosity of the medium. The distribution of the liquid within the flask has been modelled by the intersection between the rotational hyperboloid of the liquid and the inner wall of the shaking flask. This model allows for the calculation of the specific exchange area (a), the mass transfer coefficient (k(L)) and the maximum oxygen transfer capacity (OTR(max)) for given operating conditions and requires no fitting parameters. Read More

    Introduction to advantages and problems of shaken cultures.
    Biochem Eng J 2001 Mar;7(2):91-98
    Department of Biochemical Engineering, Aachen University of Technology, Sammelbau Biologie, D-52074, Aachen, Germany
    Shaking bioreactors are the most frequently used reaction vessels in biotechnology and have been so for many decades. In spite of their large practical importance, very little is known about the characteristic properties of shaken cultures from an engineering point of view. The few publications available contain to some extent contradicting statements and conflicting advice concerning the correct operating conditions of shaking bioreactors. Read More

    Effects of N-acetylation degree on N-acetylated chitosan hydrolysis with commercially available and modified pectinases.
    Biochem Eng J 2001 Jan;7(1):85-88
    Kajiuchi Laboratory, Department of International Development Engineering, Graduated School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, 152-8550, Tokyo, Japan
    Three types of N-acetylated chitosans (NACs) with different degrees of acetylation (DA) were prepared and used as a substrate for enzymatic hydrolysis with a commercially available pectinase and a modified one. Pectinase modification was conducted using polyalkyleneoxide-maleic anhydride copolymer (PEO-MA copolymer). The effects of DA on enzymatic reaction with native and modified pectinases were investigated experimentally. Read More

    Biosorption of reactive dyes by dried activated sludge: equilibrium and kinetic modelling.
    Biochem Eng J 2001 Jan;7(1):79-84
    Chemical Engineering Department, Hacettepe University, 06532 Beytepe, Ankara, Turkey
    The biosorption of reactive dyes (Reactive Blue 2 - RB2 and Reactive Yellow 2 - RY2) onto dried activated sludge was investigated. The dye binding capacity of biosorbent was shown as a function of initial pH, initial dye concentration and type of dye. The equilibrium data fitted very well to both the Freundlich and Langmuir adsorption models. Read More

    Perfluorocarbon-mediated aeration applied to recombinant protein production by virus-infected insect cells.
    Biochem Eng J 2001 Jan;7(1):69-78
    Department of Materials Process Engineering and Applied Chemistry for Environments, Akita University, 1-1 Tegata, 010-8502, Akita, Japan
    Perfluorocarbon (PFC) was used as an oxygen carrier in the cultures of insect cells and virus-infected insect cells. The cell suspensions were placed on a planar layer of PFC, which was re-oxygenated in an outer aeration unit and continuously recirculated, and were agitated by two sets of impeller blades, lower one of which was set in such a way that the ridge of the blade touched the PFC layer. The maximum cell density attained in the PFC-mediated aeration culture was higher than that in surface aeration culture. Read More

    A mathematical model of the cell cycle of a hybridoma cell line.
    Biochem Eng J 2001 Jan;7(1):49-68
    Department of Chemical and Process Engineering, School of Engineering in the Environment, University of Surrey, Surrey GU2 5XH, Guildford, UK
    A one-dimensional age-based population balance model of the cell cycle is proposed for a mouse-mouse hybridoma cell line (mm321) producing immunoglobulin G antibody to paraquat. It includes the four conventional cell cycle phases, however, G1 is divided into two parts (G1a and G1b). Two additional phases have been added, a non-cycling state G1', and a pre-death phase D. Read More

    Probabilistic neural networks using Bayesian decision strategies and a modified Gompertz model for growth phase classification in the batch culture of Bacillus subtilis.
    Biochem Eng J 2001 Jan;7(1):41-48
    Department of Chemical and Bioresource Engineering, Colorado State University, 100 Glover Building, 80523, Fort Collins, CO, USA
    Probabilistic neural networks (PNNs) were used in conjunction with the Gompertz model for bacterial growth to classify the lag, logarithmic, and stationary phases in a batch process. Using the fermentation time and the optical density of diluted cell suspensions, sampled from a culture of Bacillus subtilis, PNNs enabled a reliable determination of the growth phases. Based on a Bayesian decision strategy, the Gompertz based PNN used newly proposed definition of the lag and logarithmic phases to estimate the latent, logarithmic and stationary phases. Read More

    Cultivation of Bacillus thuringiensis in an airlift reactor with wire mesh draft tubes.
    Biochem Eng J 2001 Jan;7(1):35-39
    Department of Chemical Engineering, National Tsing Hua University, 30043, ROC, Hsinchu, Taiwan
    An aeration strategy was proposed for foam control in an airlift reactor with double wire mesh draft tubes. The airlift reactor was employed in the cultivation of Bacillus thuringiensis for thuringiensin production. The aeration strategy involved two situations. Read More

    Phase transfer and biocatalyst behaviour during biotransformation of beta-ionone in a two-phase liquid system by immobilised Aspergillus niger.
    Biochem Eng J 2001 Jan;7(1):27-34
    Laboratoire de Génie Chimique Biologique, Université Blaise Pascal, F-63177 Cedex, Aubière, France
    The biotransformation of beta-ionone by Aspergillus niger IFO 8541 entrapped in Ca-alginate beads was investigated in a two-phase liquid system, due to the low aqueous solubility of the precursor. Modelling of phase transfer processes of the substrate demonstrated that the solute was transferred from the organic droplets to the gas, giving a loss by stripping, and then from the gas to the aqueous solution where a chemical degradation occurred. The biological reaction took place after direct precursor transfer from the organic layer to the biocatalyst by surface adsorption. Read More

    On-line monitoring and controlling system for fermentation processes.
    Biochem Eng J 2001 Jan;7(1):17-25
    Department of Chemical Engineering, National Chung Cheng University, 62107, Chia-Yi, Taiwan
    A personal computer-based on-line monitoring and controlling system was developed for the fermentation of microorganism. The on-line HPLC system for the analysis of glucose and ethanol in the fermentation broth was connected to the fermenter via an auto-sampling equipment, which could perform the pipetting, filtration and dilution of the sample and final injection onto the HPLC through automation based on a programmed procedure. The A/D and D/A interfaces were equipped in order to process the signals from electrodes and from the detector of HPLC, and to direct the feed pumps, the motor of stirrer and gas flow-rate controller. Read More

    Modeling of antibiotics production in magneto three-phase airlift fermenter.
    Biochem Eng J 2001 Jan;7(1):7-16
    Department of Chemical Engineering, Amman College for Engineering Technology, Al-Balqa' Applied University, P.O. Box 340558, Marka, Amman, Jordan
    A mathematical model is developed to describe the performance of a three-phase airlift reactor utilizing a transverse magnetic field. The model is based on the complete mixing model for the bulk of liquid phase and on the Michaelis-Menten kinetics. The model equations are solved by the explicit finite difference method from transient to steady state conditions. Read More

    1 OF 2