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Biotechnology Journal

Pia Gruber, Marco P C Marques, Philipp Sulzer, Roland Wohlgemuth, Torsten Mayr, Frank Baganz, Nicolas Szita
Monitoring and control of pH is essential for the control of reaction conditions and reaction progress for any biocatalytic or biotechnological process. Microfluidic enzymatic reactors are increasingly proposed for process development, however typically lack instrumentation, such as pH monitoring. We present a microfluidic side-entry reactor (μSER) and demonstrate for the first time real-time pH monitoring of the progression of an enzymatic reaction in a microfluidic reactor as a first step towards achieving pH control...
January 20, 2017: Biotechnology Journal
Mingzhi Liang, Stefanie Frank, Heinrich Lünsdorf, Martin J Warren, Michael B Prentice
Processes for the biological removal of phosphate from wastewater rely on temporary manipulation of bacterial polyphosphate levels by phased environmental stimuli. In E. coli polyphosphate levels are controlled via the polyphosphate-synthesizing enzyme polyphosphate kinase (PPK1) and exopolyphosphatases (PPX and GPPA), and are temporarily enhanced by PPK1 overexpression and reduced by PPX overexpression. We hypothesised that partitioning PPK1 from cytoplasmic exopolyphosphatases would increase and stabilise E...
January 20, 2017: Biotechnology Journal
Kathrin Halfter, Barbara Mayer
Current decision-guiding algorithms in cancer drug treatment are based on decades of research and numerous clinical trials. For the majority of patients, this data is successfully applied for a systemic disease management. For a number of patients however, treatment stratification according to clinically based risk criteria will not be sufficient. The most effective treatment options are ideally identified prior to the start of clinical drug therapy. This review will discuss the implementation of three-dimensional (3D) cell culture models as a preclinical testing paradigm for the efficacy of clinical cancer treatment...
January 18, 2017: Biotechnology Journal
Jan M Klenk, Bernd A Nebel, Joanne L Porter, Justyna K Kulig, Shaneela A Hussain, Sven M Richter, Michele Tavanti, Nicholas J Turner, Martin A Hayes, Bernhard Hauer, Sabine L Flitsch
P450 monooxygenases are able to catalyse the highly regio- and stereoselective oxidations of many organic molecules. However, the scale-up of such bio-oxidations remains challenging due to the often-low activity, level of expression and stability of P450 biocatalysts. Despite these challenges they are increasingly desirable as recombinant biocatalysts, particularly for the production of drug metabolites. Diclofenac is a widely used anti-inflammatory drug that is persistent in the environment along with the 4'- and 5-hydroxy metabolites...
January 18, 2017: Biotechnology Journal
Matthias Brunner, Philipp Braun, Philipp Doppler, Christoph Posch, Dirk Behrens, Christoph Herwig, Jens Fricke
Due to high mixing times and base addition from top of the vessel, pH inhomogeneities are most likely to occur during large-scale mammalian processes. The goal of this study was to set-up a scale-down model of a 10-12 m(3) stirred tank bioreactor and to investigate the effect of pH perturbations on CHO cell physiology and process performance. Short-term changes in extracellular pH were hypothesized to affect intracellular pH and thus cell physiology. Therefore, batch fermentations, including pH shifts to 9...
January 12, 2017: Biotechnology Journal
Mauryn C Nweke, Mark Turmaine, R Graham McCartney, Daniel G Bracewell
The drying of chromatography resins prior to scanning electron microscopy is critical to image resolution and hence understanding of the bead structure at sub-micron level. Achieving suitable drying conditions is especially important with agarose-based chromatography resins, as over-drying may cause artefact formation, bead damage and alterations to ultrastructural properties; and under-drying does not provide sufficient resolution for visualisation under SEM. This paper compares and contrasts the effects of two drying techniques, critical point drying and freeze drying, on the morphology of two agarose based resins (MabSelect(TM) : dw ~ 85 µm and Capto(TM) Adhere: dw ~75 µm) and provides a complete method for both...
December 28, 2016: Biotechnology Journal
Clarissa Dziggel, Holger Schäfer, Michael Wink
Plant secondary metabolites exhibit a variety of biological activities and therefore serve as valuable therapeutics or flavoring compounds. However, the small amounts isolated from plants often cannot meet market demands. This led to the exploration of other, more profitable methods for their production, including plant cell culture systems, chemical synthesis and biotechnological production in microbial hosts. The biotechnological production can be pursued by reconstructing metabolic pathways in selected microbial systems...
December 23, 2016: Biotechnology Journal
Lars Freier, Eric von Lieres
Biotechnological separation processes are routinely designed and optimized using parallel high-throughput experiments and/or serial experiments. Well-characterized processes can further be optimized using mechanistic models. In all these cases - serial/parallel experiments and modeling - iterative strategies are customarily applied for planning novel experiments/simulations based on the previously acquired knowledge. Process optimization is typically complicated by conflicting design targets, such as productivity and yield...
December 23, 2016: Biotechnology Journal
Brandon Engebretson, Zachary R Mussett, Vassilios I Sikavitsas
Chemical and mechanical stimulation, when properly utilized, positively influence both the differentiation of in vitro cultured stem cells and the quality of the deposited extracellular matrix (ECM). This study aimed to find if cell-free extract from primary tenocytes can positively affect the development of a tissue-engineered tendon construct, consisting of a human umbilical vein (HUV) seeded with mesenchymal stem cells (MSCs) subjected to cyclical mechanical stimulation. The tenocytic cell-free extract possesses biological material from tendon cells that could potentially influence MSC tenocytic differentiation and construct development...
December 23, 2016: Biotechnology Journal
Ang-Chen Tsai, Yijun Liu, Xuegang Yuan, Ravindran Chella, Teng Ma
Human mesenchymal stem cells (hMSCs) are primary candidates in cell therapy and regenerative medicine but preserving their therapeutic potency following culture expansion is a significant challenge. hMSCs can spontaneously assemble into three-dimensional (3D) aggregates that enhance their regenerative properties. The present study investigated the impact of hydrodynamics conditions on hMSC aggregation kinetics under controlled rocking motion. While various laboratory methods have been developed for hMSC aggregate production, the rocking platform provides gentle mixing and can be scaled up using large bags as in wave motion bioreactors...
December 20, 2016: Biotechnology Journal
Arch Creasy, Gregory Barker, Giorgio Carta
A methodology is presented to predict protein elution behavior from an ion exchange column using both individual or combined pH and salt gradients based on high-throughput batch isotherm data. The buffer compositions were first optimized to generate linear pH gradients from pH 5.5 to 7 with defined concentrations of sodium chloride. Next, high-throughput batch isotherm data were collected for a monoclonal antibody on the cation exchange resin POROS XS over a range of protein concentrations, salt concentrations, and solution pH...
December 19, 2016: Biotechnology Journal
Getachew S Molla, Birhanu M Kinfu, Jennifer Chow, Wolfgang Streit, Roland Wohlgemuth, Andreas Liese
Enantiopure L-glyceraldehyde-3-phosphate (L-GAP) is a useful building block in natural biological and synthetic processes. A biocatalytic process using glycerol kinase from Cellulomonas sp. (EC catalyzed phosphorylation of L-glyceraldehyde (L-GA) by ATP was used for the synthesis of L-GAP. L-GAP has a half-life of 6.86 h under reaction conditions. The activity this enzyme depends on the Mg(2+) to ATP molar ratio showing maximum activity at the optimum molar ratio of 0.7. A kinetic model was developed and validated showing a 2-D correlation of 99...
December 19, 2016: Biotechnology Journal
Ming-Shan Kao, Stephen Huang, Wei-Lin Chang, Ming-Fa Hsieh, Chun-Jen Huang, Richard L Gallo, Chun-Ming Huang
Recent creation of a Unified Microbiome Initiative (UMI) has the aim of understanding how microbes interact with each other and with us. When pathogenic Staphylococcus aureus (S. aureus) infects the skin, the interplay between S. aureus and skin commensal bacteria occurs. Our previous data revealed that skin commensal bacteria can mediate fermentation against the growth of USA300, a community-acquired methicillin-resistant S. aureus MRSA (CA-MRSA). By using a fermentation process with solid media on a small scale, we define poly(ethylene glycol) dimethacrylate (PEG-DMA) as a selective fermentation initiator (SFI) which can specifically intensify the probiotic ability of skin commensal Staphylococcus epidermidis (S...
December 16, 2016: Biotechnology Journal
Margarita-Elena Papandreou, Nektarios Tavernarakis
Cell homeostasis requires the concerted action of cellular pathways involved in degradation, trafficking and intercellular communication, which are interlinked to satisfy the cell's needs upon demand. Defects in these pathways instigate the development of several age-related pathologies, such as neurodegenerative and chronic inflammatory diseases. Autophagy is an evolutionarily conserved and tightly regulated process of degrading cellular constituents. The endosomal and vesicular trafficking pathways contribute to this regulation and share common features with the autophagic process...
December 15, 2016: Biotechnology Journal
Thiemo C Huuk, Tobias Hahn, Katharina Doninger, Jan Griesbach, Stefan Hepbildikler, Jürgen Hubbuch
A main requirement for the implementation of model-based process development in industry is the capability of the model to predict high protein load densities. The frequently used steric mass action isotherm assumes a thermodynamically ideal system and, hence constant activity coefficients. In this manuscript, an industrial antibody purification problem under high load conditions is considered where this assumption does not hold. The high protein load densities, as commonly applied in industrial downstream processing, may lead to complex elution peak shapes...
December 15, 2016: Biotechnology Journal
Gauri V Deodhar, Marisa L Adams, Brian G Trewyn
Protein therapeutics are promising candidates for disease treatment due to their high specificity and minimal adverse side effects; however, targeted protein delivery to specific sites has proven challenging. Mesoporous silica nanoparticles (MSN) have demonstrated to be ideal candidates for this application, given their high loading capacity, biocompatibility, and ability to protect host molecules from degradation. These materials exhibit tunable pore sizes, shapes and volumes, and surfaces which can be easily functionalized...
December 14, 2016: Biotechnology Journal
Won Jun Kim, Jung Ho Ahn, Hyun Uk Kim, Tae Yong Kim, Sang Yup Lee
Mannheimia succiniciproducens, a capnophilic gram-negative rumen bacterium, has been employed for the efficient production of succinic acid. Although M. succiniciproducens metabolism was previously studied using a genome-scale metabolic model, more metabolic characteristics are to be understood. To this end, we used elementary mode analysis accompanied with clustering ('EMC' analysis) to gain further insights on metabolic characteristics of M. succiniciproducens allowing efficient succinic acid production. Elementary modes (EMs) generated from the central carbon metabolic network of M...
December 14, 2016: Biotechnology Journal
Vítor E Santo, Sofia P Rebelo, Marta F Estrada, Paula M Alves, Erwin Boghaert, Catarina Brito
There is cumulating evidence that in vitro 3D tumor models with increased physiological relevance can improve the predictive value of pre-clinical research and ultimately contribute to achieve decisions earlier during the development of cancer-targeted therapies. Due to the role of tumor microenvironment in the response of tumor cells to therapeutics, the incorporation of different elements of the tumor niche on cell model design is expected to contribute to the establishment of more predictive in vitro tumor models...
December 14, 2016: Biotechnology Journal
Cheng-Yu Chung, Qiong Wang, Shuang Yang, Bojiao Yin, Hui Zhang, Michael Betenbaugh
Immunoglobin G with α-2,6 sialylation has been reported to have an impact on antibody-depend cellular cytotoxicity and anti-inflammatory efficacy. However, production of antibodies with α-2,6 sialylation from Chinese hamster ovary cells is challenging due to the inaccessibility of sialyltransferases for the heavy chain N-glycan site and the presence of exclusively α-2,3 sialyltransferases. In this study, combining mutations on the Fc regions to allow sialyltransferase accessibility with overexpression of α-2,6 sialyltransferase produced IgG with significant levels of both α-2,6 and α-2,3 sialylation...
December 12, 2016: Biotechnology Journal
Evan Wells, Anne Skaja Robinson
Recombinant proteins offer many therapeutic advantages unavailable in traditional small molecule drugs, but the need for cellular versus chemical synthesis complicates production. Avenues for producing therapeutic biologics are continuously expanding, and developments in biochemistry, cell biology, and bioengineering fuel new discoveries that promise safer, more efficient, and cheaper drugs for consumers. Numerous approaches to express recombinant proteins exist, but Escherichia coli, Saccharomyces cerevisiae, and mammalian systems (e...
December 9, 2016: Biotechnology Journal
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