Biotechnology and BioengineeringThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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1124 records returned

Hydrodynamic modulation of embryonic stem cell differentiation by rotary orbital suspension cultureEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Embryonic stem cells (ESCs) can differentiate into all somatic cell types, but the development of effective strategies to direct ESC fate is dependent upon defining environmental parameters capable of influencing cell phenotype. ESCs are commonly differentiated via cell aggregates referred to as embryoid bodies (EBs), but current culture methods, such as hanging drop and static suspension, yield relatively few or heterogeneous populations of EBs. Alternatively, rotary orbital suspension culture enhances EB formation efficiency, cell yield, and homogeneity without adversely affecting differentiation. Thus, the objective of ...
Source: Biotechnology and Bioengineering - November 19, 2009 Category: Biomedical Science Authors: Carolyn Y. Sargent, Geoffrey Y. Berguig, Melissa A. Kinney, Luke A. Hiatt, Richard L. Carpenedo, R. Eric Berson, Todd C. McDevitt Source Type: journals

Enhancement of ethanol and biogas production from high-crystalline cellulose by different modes of NMO pretreatmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pretreatment of high-crystalline cellulose with N-methyl-morpholine-N-oxide (NMO or NMMO) to improve bioethanol and biogas production was investigated. The pretreatments were performed at 90 and 120°C for 0.5-15 h in three different modes, including dissolution (85% NMO), ballooning (79% NMO), and swelling (73% NMO). The pretreated materials were then enzymatically hydrolyzed and fermented to ethanol or anaerobically digested to biogas (methane). The pretreatment at 85% NMO, 120°C and 2.5 h resulted in 100% yield in the subsequent enzymatic hydrolysis and around 150% improvement in the yield of ethanol compared to the un...
Source: Biotechnology and Bioengineering - November 13, 2009 Category: Biomedical Science Authors: Azam Jeihanipour, Keikhosro Karimi, Mohammad J. Taherzadeh Source Type: journals

CHO gene expression profiling in biopharmaceutical process analysis and designEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Increase in both productivity and product yields in biopharmaceutical process development with recombinant protein producing mammalian cells can be mainly attributed to the advancements in cell line development, media, and process optimization. Only recently, genome-scale technologies enable a system-level analysis to elucidate the complex biomolecular basis of protein production in mammalian cells promising an increased process understanding and the deduction of knowledge-based approaches for further process optimization. Here, the use of gene expression profiling for the analysis of a low titer (LT) and high titer (HT) f...
Source: Biotechnology and Bioengineering - November 6, 2009 Category: Biomedical Science Authors: Jochen Schaub, Christoph Clemens, Peter Schorn, Tobias Hildebrandt, Werner Rust, Detlev Mennerich, Hitto Kaufmann, Torsten W. Schulz Source Type: journals

Modeling the influence of cyclodextrins on oral absorption of low solubility drugs: II. Experimental validationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A model was developed for predicting the influence of cyclodextrins (CDs) delivered as a physical mixture with drug on oral absorption. CDs are cyclic oligosaccharides which form inclusion complexes with many drugs and are often used as solubilizing agents. The purpose of this work is to compare the simulation predictions with in vitro as well as in vivo experimental results to test the model's ability to capture the influence of CD on key processes in the gastrointestinal (GI) tract environment. Dissolution and absorption kinetics of low solubility drugs (Naproxen and Nifedipine) were tested in the presence and absence of...
Source: Biotechnology and Bioengineering - November 1, 2009 Category: Biomedical Science Authors: Ece Dilber Gamsiz, Lee Miller, Avinash G. Thombre, Imran Ahmed, Rebecca Lyn Carrier Source Type: journals

An unbiased sensitivity analysis reveals important parameters controlling periodicity of circadian clockEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we propose a computational approach to determine the relative importance of parameters controlling the performance of the circadian clock in Drosophila. While previous attempts to sensitivity analysis largely depend on the knowledge of model parameters which are generally unknown, our study depicts a consistent picture of sensitivity assessment for a large number of parameters, even when the values of these parameters are not available in vivo. The resulting parametric sensitivity analysis suggests that PER/TIM negative loop is critical to maintain the stable periodicity of the circadian clock, which is cons...
Source: Biotechnology and Bioengineering - October 28, 2009 Category: Biomedical Science Authors: Zhi Xie, Don Kulasiri, Sandhya Samarasinghe, Jiang Qian Source Type: journals

Micro-scale bioreactors that predict production scaleEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 26, 2009 Category: Biomedical Science Source Type: journals

Overcoming diffusional limitations in vascular tissue engineering with transmural flowEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 26, 2009 Category: Biomedical Science Source Type: journals

Old wine in new skinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 26, 2009 Category: Biomedical Science Source Type: journals

Predictive biodegradation made feasibleEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 26, 2009 Category: Biomedical Science Source Type: journals

Development of an Ibuprofen-releasing biodegradable PLA/PGA electrospun scaffold for tissue regenerationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fib...
Source: Biotechnology and Bioengineering - October 21, 2009 Category: Biomedical Science Authors: Irene Cantón, Robert Mckean, Mirren Charnley, Keith A. Blackwood, Calogero Fiorica, Anthony J. Ryan, Sheila MacNeil Source Type: journals

Profiling of host cell proteins by two-dimensional difference gel electrophoresis (2D-DIGE): Implications for downstream process developmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article describes the use of a comparative proteomic profiling method viz. two-dimensional difference gel electrophoresis (2D-DIGE) to examine HCP composition in the harvest stream of CHO cell culture. The effect of upstream process parameters such as cell culture media, bioreactor control strategy, feeding strategy, and cell culture duration/cell viability on HCP profile was examined using this technique. Among all the parameters studied, cell viability generated the most significant changes on the HCP profile. 2D-DIGE was also used to compare the HCP differences between monoclonal antibody producing and null cell cu...
Source: Biotechnology and Bioengineering - October 19, 2009 Category: Biomedical Science Authors: Mi Jin, Nicolas Szapiel, Jennifer Zhang, John Hickey, Sanchayita Ghose Source Type: journals

Dynamic measurement of the volumetric oxygen transfer coefficient in fermentation systemsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 18, 2009 Category: Biomedical Science Authors: B. Bandyopadhyay, A. E. Humphrey, H. Taguchi, Introduction by Govind Rao Source Type: journals

Enhanced tubular scaffold design with gradient layersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 18, 2009 Category: Biomedical Science Source Type: journals

Observation without provocation: Using electrochemical impedance spectroscopy to understand bacterial respiration in microbial fuel cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 18, 2009 Category: Biomedical Science Source Type: journals

Improved subtilase variant better suited for industrial applicationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 18, 2009 Category: Biomedical Science Source Type: journals

Enzymatic synthesis of specialty surfactantsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - October 18, 2009 Category: Biomedical Science Source Type: journals

A DIGE approach for the assessment of differential expression of the CHO proteome under sodium butyrate addition: Effect of Bcl-xL overexpressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bcl-xL, a member of the Bcl-2 family, is known to inhibit apoptosis of recombinant Chinese hamster ovary (rCHO) cells induced by the addition of sodium butyrate (NaBu), which is used for the elevated expression of recombinant protein. In order to understand the intracellular effects of Bcl-xL overexpression on CHO cells treated with NaBu, changes to the proteome caused by controlled Bcl-xL expression in rCHO cells producing erythropoietin (EPO) in the presence of 3 mM NaBu were evaluated using two-dimensional differential in-gel electrophoresis (2D-DIGE) and MS analysis. The consequences of Bcl-xL overexpression were not l...
Source: Biotechnology and Bioengineering - October 13, 2009 Category: Biomedical Science Authors: Jong Youn Baik, Gyun Min Lee Source Type: journals

Microfluidic biochip for the perifusion of precision-cut rat liver slices for metabolism and toxicology studiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article describes a novel in vitro system for the incubation of precision-cut liver slices (PCLS) under flow conditions, based on a poly(dimethylsiloxane) (PDMS) device containing 25-µL microchambers for integration of the slices. The microdevice is coupled to a perifusion system, which enables a constant delivery of nutrients and oxygen and a continuous removal of waste products. Both a highly controlled incubation environment and high metabolite detection sensitivity could be achieved using microfluidics. Liver slices were viable for at least 24 h in the microdevice. The compound, 7-ethoxycoumarin (7-EC), was chose...
Source: Biotechnology and Bioengineering - October 8, 2009 Category: Biomedical Science Authors: Paul M. van Midwoud, Geny M.M. Groothuis, Marjolijn T. Merema, Elisabeth Verpoorte Source Type: journals

Considerations for the design and construction of a synthetic platform cell for biotechnological applicationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The design and construction of an artificial bacterial cell could revolutionize biotechnological processes and technologies. A functional platform cell that can be easily customized for a pre-defined task would be useful for applications from producing therapeutics to decontaminating waste streams. The platform cell must be robust and highly efficient. A biotechnological platform cell is related to the concept of a minimal cell, but several factors beyond those necessary for a minimal cell must be considered for a synthetic organism designed for biotechnological applications. Namely, a platform cell must exhibit robust cel...
Source: Biotechnology and Bioengineering - October 8, 2009 Category: Biomedical Science Authors: P.L. Foley, M.L. Shuler Source Type: journals

Genome-scale analysis of library sorting (GALibSo): Isolation of secretion enhancing factors for recombinant protein production in Pichia pastorisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A method combining fluorescence activated cell sorting (FACS) and DNA microarray assisted clone identification was developed and termed Genome-Scale Analysis of Library Sorting (GALibSo). Genes enhancing the production of secreted heterologous proteins in Pichia pastoris were identified out of a cDNA library by cell surface display and FACS. The trends of gene enrichment during consecutive FACS rounds were monitored by DNA microarrays. In a case study a P. pastoris cDNA library was co-expressed in a strain secreting the Fab fragment of a monoclonal antibody against human immunodeficiency virus type 1 as a model protein. Th...
Source: Biotechnology and Bioengineering - October 8, 2009 Category: Biomedical Science Authors: Gerhard Stadlmayr, Katrin Benakovitsch, Brigitte Gasser, Diethard Mattanovich, Michael Sauer Source Type: journals

Mixtures of hemoglobin-based oxygen carriers and perfluorocarbons exhibit a synergistic effect in oxygenating hepatic hollow fiber bioreactorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hepatic hollow fiber (HF) bioreactors are being developed for use as bioartificial liver assist devices (BLADs). In general, BLADs suffer from O2 limited transport, which reduces their performance. This modeling study seeks to investigate if O2 carrying solutions consisting of mixtures of hemoglobin-based oxygen carriers (HBOCs) and perfluorocarbons (PFCs) can enhance O2 transport to hepatocytes cultured in the extra capillary space (ECS) of HF bioreactors. We simulated supplementing the circulating cell culture media stream of the HF bioreactor with a mixture containing these two types of oxygen carriers (HBOCs and PFCs)....
Source: Biotechnology and Bioengineering - October 8, 2009 Category: Biomedical Science Authors: Guo Chen, Andre F. Palmer Source Type: journals

Isomerization in the CDR2 of a monoclonal antibody: Binding analysis and factors that influence the isomerization rateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Isomerization of a monoclonal antibody is one of the common routes of protein degradation. An isomerization in the complementarity-determining region (CDR) was found previously and is investigated in depth in this work. Affinity analysis proves that the antibody with one isomerized heavy chain has lower binding. Binding constants were determined, and exhibited a slower on-rate in conjunction with a faster off-rate for this isomerization. To determine the role of the buffer on the rate of isomerization, this antibody was incubated in various matrices and the amount of isomerized antibody was determined by hydrophobic intera...
Source: Biotechnology and Bioengineering - October 5, 2009 Category: Biomedical Science Authors: Lawrence W. Dick Jr, Difei Qiu, Rosie B. Wong, Kuang-Chuan Cheng Source Type: journals

Investigating the role of native propionyl-CoA and methylmalonyl-CoA metabolism on heterologous polyketide production in Escherichia coliEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the sbm, ygfG, and ygfH genes were individually deleted and over-expressed to investigate their effect on heterologous 6dEB production. Our results indicate that the deletion and over-expression of sbm did not influence 6dEB production; ygfG over-expression reduced 6dEB production by fourfold while ygfH deletion increased 6dEB titers from 65 to 129 mg/L in shake flask experiments. It was also found that native E. coli metabolism could support 6dEB biosynthesis in the absence of exogenous propionate and the substrate provision pcc genes. Lastly, the effect of the ygfH deletion was tested in batch bioreactor c...
Source: Biotechnology and Bioengineering - October 5, 2009 Category: Biomedical Science Authors: Haoran Zhang, Brett A. Boghigian, Blaine A. Pfeifer Source Type: journals

Theoretical investigation of the sequential reductive dechlorination pathways of chlorobenzenes and chloroanilinesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The distribution of product isomers during the sequential reductive dechlorination of pentachloroaniline (PCA) and pentachlorobenzene (PeCB) was examined based on calculated thermodynamic, chromatographic, and electronic properties and then compared to the product distribution achieved by enrichment cultures. The dechlorination pathway analysis based on free energy considerations matched 78% and 67% of the experimental results for the sequential reductive dechlorination of chlorobenzenes (CBs) and chloroanilines (CAs), respectively. Chromatographic properties of CBs and CAs were able to explain some but not all of the reac...
Source: Biotechnology and Bioengineering - October 5, 2009 Category: Biomedical Science Authors: Didem Okutman Tas, Mark T. Prytula, James A. Mulholland, Spyros G. Pavlostathis Source Type: journals

Maintenance of pluripotency in human embryonic stem cells cultured on a synthetic substrate in conditioned mediumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Realizing the potential clinical and industrial applications of human embryonic stem cells (hESCs) is limited by the need for costly, labile, or undefined growth substrates. Here we demonstrate that trypsin passaging of the hESC lines, HUES7 and NOTT1, on oxygen plasma etched tissue culture polystyrene (PE-TCPS) in conditioned medium is compatible with pluripotency. This synthetic culture surface is stable at room temperature for at least a year and is readily prepared by placing polystyrene substrates in a radio frequency oxygen plasma generator for 5 min. Modification of the polystyrene surface chemistry by plasma etchin...
Source: Biotechnology and Bioengineering - October 1, 2009 Category: Biomedical Science Authors: Magdalena M. Mahlstedt, David Anderson, James S. Sharp, Roger McGilvray, Maria D. Barbadillo Muñoz, Lee D. Buttery, Morgan R. Alexander, Felicity R.A.J. Rose, Chris Denning Source Type: journals

Power production in MFCs inoculated with Shewanella oneidensis MR-1 or mixed culturesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Power densities and oxidation-reduction potentials (ORPs) of MFCs containing a pure culture of Shewanella oneidensis MR-1 were compared to mixed cultures (wastewater inoculum) in cube shaped, 1-, 2-, and 3-bottle batch-fed MFC reactor configurations. The reactor architecture influenced the relative power produced by the different inocula, with the mixed culture generating 68-480% more power than MR-1 in each MFC configuration. The mixed culture produced the maximum power density of 858 ± 9 mW m-2 in the cubic MFC, while MR-1 produced 148 ± 20 mW m-2. The higher power by the mixed culture was primarily a result of lower i...
Source: Biotechnology and Bioengineering - September 28, 2009 Category: Biomedical Science Authors: Valerie J. Watson, Bruce E. Logan Source Type: journals

Modeling of flow-induced shear stress applied on 3D cellular scaffolds: Implications for vascular tissue engineeringEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Novel tissue-culture bioreactors employ flow-induced shear stress as a means of mechanical stimulation of cells. We developed a computational fluid dynamics model of the complex three-dimensional (3D) microstructure of a porous scaffold incubated in a direct perfusion bioreactor. Our model was designed to predict high shear-stress values within the physiological range of those naturally sensed by vascular cells (1-10 dyne/cm2), and will thereby provide suitable conditions for vascular tissue-engineering experiments. The model also accounts for cellular growth, which was designed as an added cell layer grown on all scaffold...
Source: Biotechnology and Bioengineering - September 28, 2009 Category: Biomedical Science Authors: Ayelet Lesman, Yaron Blinder, Shulamit Levenberg Source Type: journals

High-pressure systems for gas-phase free continuous incubation of enriched marine microbial communities performing anaerobic oxidation of methaneEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Novel high-pressure biotechnical systems that were developed and applied for the study of anaerobic oxidation of methane (AOM) are described. The systems, referred to as high-pressure continuous incubation system (HP-CI system) and high-pressure manifold-incubation system (HP-MI system), allow for batch, fed-batch, and continuous gas-phase free incubation at high concentrations of dissolved methane and were designed to meet specific demands for studying environmental regulation and kinetics as well as for enriching microbial biomass in long-term incubation. Anoxic medium is saturated with methane in the first technical sta...
Source: Biotechnology and Bioengineering - September 28, 2009 Category: Biomedical Science Authors: Christian Deusner, Volker Meyer, Timothy G. Ferdelman Source Type: journals

Degradation of an Fc-fusion recombinant protein by host cell proteases: Identification of a CHO cathepsin D proteaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study is an example of how quality and stability of therapeutic recombinant molecules are strongly influenced by cell culture parameters. Biotechnol. Bioeng. © 2009 Wiley Periodicals, Inc. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 26, 2009 Category: Biomedical Science Authors: Flavie Robert, Horst Bierau, Mara Rossi, David Agugiaro, Thomas Soranzo, Hervé Broly, Christine Mitchell-Logean Source Type: journals

Computational framework for predictive biodegradationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
As increasing amounts of anthropogenic chemicals are released into the environment, it is vital to human health and the preservation of ecosystems to evaluate the fate of these chemicals in the environment. It is useful to predict whether a particular compound is biodegradable and if alternate routes can be engineered for compounds already known to be biodegradable. In this work, we describe a computational framework (called BNICE) that can be used for the prediction of novel biodegradation pathways of xenobiotics. The framework was applied to 4-chlorobiphenyl, phenanthrene, [gamma]-hexachlorocyclohexane, and 1,2,4-trichlo...
Source: Biotechnology and Bioengineering - September 25, 2009 Category: Biomedical Science Authors: Stacey D. Finley, Linda J. Broadbelt, Vassily Hatzimanikatis Source Type: journals

Surface-directed assembly of cell-laden microgelsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell-laden microscale hydrogels (microgels) can be used as tissue building blocks and assembled to create 3D tissue constructs with well-defined microarchitecture. In this article, we present a bottom-up approach to achieve microgel assembly on a patterned surface. Driven by surface tension, the hydrophilic microgels can be assembled into well-defined shapes on a glass surface patterned with hydrophobic and hydrophilic regions. We found that the cuboidic microgels ([sim]100-200 µm in width) could self-assemble into defined shapes with high fidelity to the surface patterns. The microgel assembly process was improved by inc...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Yanan Du, Majid Ghodousi, Edward Lo, Mahesh K. Vidula, Onur Emiroglu, Ali Khademhosseini Source Type: journals

Computational study of the drag and oscillatory movement of biofilm streamers in fast flowsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a state of the art two-dimensional fluid-structure interaction model of biofilm streamers is developed, which implements a transient coupling between the fluid and biofilm mechanics. Hereby, it is clearly shown that formation of a Kármán vortex street behind the streamer body is the main source of the periodic oscillation of the streamers. Additionally it is shown that the formation of streamers reduces the fluid forces which biofilm surface experiences. Biotechnol. Bioeng. © 2009 Wiley Periodicals, Inc. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Danial Taherzadeh, Cristian Picioreanu, Ulrich Küttler, Angelo Simone, Wolfgang A. Wall, Harald Horn Source Type: journals

Analysis of exposed cellulose surfaces in pretreated wood biomass using carbohydrate-binding module (CBM)-cyan fluorescent protein (CFP)Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In enzymatic saccharification of lignocellulosics, the access of the enzymes to exposed cellulose surfaces is a key initial step in triggering hydrolysis. However, knowledge of the structure-hydrolyzability relationship of the pretreated biomass is still limited. Here we used fluorescent-labeled recombinant carbohydrate-binding modules (CBMs) from Clostridium josui as specific markers for crystalline cellulose (CjCBM3) and non-crystalline cellulose (CjCBM28) to analyze the complex surfaces of wood tissues pretreated with NaOH, NaOH-Na2S (kraft pulping), hydrothermolysis, ball-milling, and organosolvolysis. Japanese cedar w...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Takeshi Kawakubo, Shuichi Karita, Yuko Araki, Shota Watanabe, Masafumi Oyadomari, Rie Takada, Fumio Tanaka, Kentaro Abe, Takahito Watanabe, Yoichi Honda, Takashi Watanabe Source Type: journals

High-throughput microarray profiling of cell wall polymers during hydrothermal pre-treatment of wheat strawEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lignocellulosic plant material is potentially a sustainable source of fermentable sugars for bioethanol production. However, a barrier to this is the high resistance or recalcitrance of plant cell walls to be hydrolyzed. Therefore, a detailed knowledge of the structural features of plant cell walls that contribute to recalcitrance is important for improving the efficiency of bioethanol production. In this work we have used a technique known as Comprehensive Microarray Polymer Profiling (CoMPP) to analyze wheat straw before and after being subjected to hydrothermal pre-treatments at four different temperatures. The CoMPP te...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Ana Alonso-Simón, Jan Bach Kristensen, Jens Øbro, Claus Felby, William G.T. Willats, Henning Jørgensen Source Type: journals

Serum-free, chemically defined medium with TGF-[beta]3 enhances functional properties of nucleus pulposus cell-laden carboxymethylcellulose hydrogel constructsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a standard serum-containing medium formulation was compared to a chemically defined, serum-free medium to determine the effect on matrix elaboration and functional properties of NP cell-laden carboxymethylcellulose (CMC) hydrogels. Additionally, both media were further supplemented with transforming growth factor-beta 3 (TGF-[beta]3). Glycosaminoglycan (GAG) content increased in both TGF-[beta]3-treated groups and was highest for treated, serum-free constructs (9.46 ± 1.51 µg GAG/mg wet weight), while there were no quantifiable GAGs in untreated serum-containing samples. Histology revealed uniform, interte...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Anna T. Reza, Steven B. Nicoll Source Type: journals

High stability of self-assembled peptide nanowires against thermal, chemical, and proteolytic attacksEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we investigated the stability of self-assembled peptide nanowires (PNWs) and nanotubes (PNTs) against thermal, chemical, proteolytic attacks, and their conformational changes upon heat treatment. PNWs and PNTs were grown by the self-assembly of diphenylalanine (Phe-Phe), a peptide building block, on solid substrates at different chemical atmospheres and temperatures. The incubation of diphenylalanine under aniline vapor at 150°C led to the formation of PNWs, while its incubation with water vapor at 25°C produced PNTs. We analyzed the stability of peptide nanostructures using multiple tools, such as electro...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Jungki Ryu, Chan Beum Park Source Type: journals

Metabolic flux analysis for recombinant protein production by Pichia pastoris using dual carbon sources: Effects of methanol feeding rateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The intracellular metabolic fluxes through the central carbon pathways in the bioprocess for recombinant human erythropoietin (rHuEPO) production by Pichia pastoris (Mut+) were calculated to investigate the metabolic effects of dual carbon sources (methanol/sorbitol) and the methanol feed rate, and to obtain a deeper understanding of the regulatory circuitry of P. pastoris, using the established stoichiometry-based model containing 102 metabolites and 141 reaction fluxes. Four fed-batch operations with (MS-) and without (M-) sorbitol were performed at three different constant specific growth rates (h-1), and denoted as M-0...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Eda Çelik, P[inodot]nar Çal[inodot]k, Stephen G. Oliver Source Type: journals

Integrated solution to purification challenges in the manufacture of a soluble recombinant protein in E. coliEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Apolipoprotein A 1 Milano (ApoA-1M), the protein component of a high-density lipoprotein (HDL) mimic with promising potential for reduction of atherosclerotic plaque, is produced at large scale by expression in E. coli. Significant difficulty with clearance of host cell proteins (HCPs) was experienced in the original manufacturing process despite a lengthy downstream purification train. Analysis of purified protein solutions and intermediate process samples led to identification of several major HCPs co-purifying with the product and a bacterial protease potentially causing a specific truncation of ApoA-1M found in the fin...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Maire H. Caparon, Kevin J. Rust, Alan K. Hunter, Joseph K. McLaughlin, Kristen E. Thomas, John T. Herberg, Robert E. Shell, Paul B. Lanter, Bruce F. Bishop, Robert L. Dufield, Xing Wang, Sa V. Ho Source Type: journals

BAK and BAX deletion using zinc-finger nucleases yields apoptosis-resistant CHO cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Anoxic and metabolic stresses in large-scale cell culture during biopharmaceutical production can induce apoptosis. Strategies designed to ameliorate the problem of apoptosis in cell culture have focused on mRNA knockdown of pro-apoptotic proteins and over-expression of anti-apoptotic ones. Apoptosis in cell culture involves mitochondrial permeabilization by the pro-apoptotic Bak and Bax proteins; activity of either protein is sufficient to permit apoptosis. We demonstrate here the complete and permanent elimination of both the Bak and Bax proteins in combination in Chinese hamster ovary (CHO) cells using zinc-finger nucle...
Source: Biotechnology and Bioengineering - September 23, 2009 Category: Biomedical Science Authors: Gregory J. Cost, Yevgeniy Freyvert, Annamaria Vafiadis, Yolanda Santiago, Jeffrey C. Miller, Edward Rebar, Trevor N. Collingwood, Andrew Snowden, Philip D. Gregory Source Type: journals

Perturbation-independent community development in low-temperature anaerobic biological wastewater treatment bioreactorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The reproducibility and stability of low- temperature anaerobic wastewater treatment systems undergoing transient perturbations was investigated. Three identical anaerobic expanded granular sludge bed-based bioreactors were used to degrade a volatile fatty acid and glucose-based wastewater under sub-ambient (15°C) conditions. The effect of a variety of environmental perturbations on bioreactor performance was assessed by chemical oxygen demand removal. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes extracted from sludge granules. Methanogenic ac...
Source: Biotechnology and Bioengineering - September 22, 2009 Category: Biomedical Science Authors: Pádhraig Madden, Fabio A. Chinalia, Anne-Marie Enright, Gavin Collins, Vincent O'Flaherty Source Type: journals

Aeration in fermentationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 20, 2009 Category: Biomedical Science Authors: Donald H. Phillips, Marvin J. Johnson, Introduction by John Villadsen Source Type: journals

3-hydroxypropionic acid, a value-added bulk chemical from glycerolEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 20, 2009 Category: Biomedical Science Source Type: journals

The "Third" factor hypothesis of freezing damageEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 20, 2009 Category: Biomedical Science Source Type: journals

An alternative approach for production of biopolymers from wasteEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 20, 2009 Category: Biomedical Science Source Type: journals

Antibody assembly in an algal chloroplastEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Biotechnology and Bioengineering)
Source: Biotechnology and Bioengineering - September 20, 2009 Category: Biomedical Science Source Type: journals

Microbioreactor array for full-factorial analysis of provision of multiple soluble factors in cellular microenvironmentsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report a scalable microbioreactor architecture which uses nested dilution structures to generate a full-factorial array of cell culture conditions. The proof-of-concept microbioreactor array produces all combinations of three concentration levels of two soluble factors (32 = 9 unique conditions in total). The full-factorial design is especially useful in optimizing soluble factor treatments and elucidating interaction effects between factors which are otherwise difficult to deconvolute. By nesting hierarchical levels of dilution structures, and designing the device purely by resistive flow (no valves are required), suit...
Source: Biotechnology and Bioengineering - September 15, 2009 Category: Biomedical Science Authors: Drew Titmarsh, Justin Cooper-White Source Type: journals

Cell placement and guidance on substrates for neurochip interfacesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Interface devices such as integrated planar patch-clamp chips are being developed to study the electrophysiological activity of neuronal networks grown in vitro. The utility of such devices will be dependent upon the ability to align neurons with interface features on the chip by controlling neuronal placement and by guiding cell connectivity. In this paper, we present a strategy to accomplish this goal. Patterned chemical modification of SiN surfaces with poly-d-lysine transferred from PDMS stamps was used to promote adhesion and guidance of cryo-preserved primary rat cortical neurons. We demonstrate that these neurons ca...
Source: Biotechnology and Bioengineering - September 13, 2009 Category: Biomedical Science Authors: Anne Charrier, Dolores Martinez, Robert Monette, Tanya Comas, Raluca Movileanu, Christophe Py, Mike Denhoff, Anthony Krantis, Geoff Mealing Source Type: journals

Development of a polishing step using a hydrophobic interaction membrane adsorber with a PER.C6®-derived recombinant antibodyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Membrane chromatography has already proven to be a powerful alternative to polishing columns in flow-through mode for contaminant removal. As flow-through utilization has expanded, membrane chromatography applications have included the capturing of large molecules, including proteins such as IgGs. Such bind-and-elute applications imply the demand for high binding capacity and larger membrane surface areas as compared to flow-through applications. Given these considerations, a new Sartobind PhenylTM membrane adsorber was developed for large-scale purification of biomolecules based on hydrophobic interaction chromatography (...
Source: Biotechnology and Bioengineering - September 7, 2009 Category: Biomedical Science Authors: Michael Kuczewski, Nathalie Fraud, Rene Faber, Gregory Zarbis-Papastoitsis Source Type: journals

Microwell engineering characterization for mammalian cell culture process developmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Experimentation in shaken microplate formats offers a potential platform technology for the rapid evaluation and optimization of cell culture conditions. Provided that cell growth and antibody production kinetics are comparable to those found in currently used shake flask systems then the microwell approach offers the possibility to obtain early process design data more cost effectively and with reduced material requirements. This work describes a detailed engineering characterization of liquid mixing and gas-liquid mass transfer in microwell systems and their impact on suspension cell cultures. For growth of murine hybrid...
Source: Biotechnology and Bioengineering - September 7, 2009 Category: Biomedical Science Authors: Timothy A. Barrett, Andrew Wu, Hu Zhang, M. Susana Levy, Gary J. Lye Source Type: journals

Prediction of protein solubility in Escherichia coli using logistic regressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this article we present a new and more accurate model for the prediction of the solubility of proteins overexpressed in the bacterium Escherichia coli. The model uses the statistical technique of logistic regression. To build this model, 32 parameters that could potentially correlate well with solubility were used. In addition, the protein database was expanded compared to those used previously. We tested several different implementations of logistic regression with varied results. The best implementation, which is the one we report, exhibits excellent overall prediction accuracies: 94% for the model and 87% by cross-va...
Source: Biotechnology and Bioengineering - September 7, 2009 Category: Biomedical Science Authors: Armando A. Diaz, Emanuele Tomba, Reese Lennarson, Rex Richard, Miguel J. Bagajewicz, Roger G. Harrison Source Type: journals