12,628 results match your criteria Biotechnology and Bioengineering [Journal]


A comparison of hMSC osteogenesis in PEG hydrogels as a function of MMP-sensitive crosslinker and crosslink density in chemically-defined medium.

Biotechnol Bioeng 2019 Feb 18. Epub 2019 Feb 18.

Department of Chemical and Biological Engineering, 3415 Colorado Ave, University of Colorado, Boulder, CO.

This study investigated osteogenesis of human mesenchymal stem cells (hMSCs) encapsulated in matrix-metalloproteinase (MMP)-sensitive poly(ethylene glycol) (PEG) hydrogels in chemically-defined medium (10 ng/ml BMP-2). Thiol-norbornene photoclick hydrogels were formed with CRGDS and crosslinkers of PEG dithiol (non-degradable), CVPLS-LYSGC (P1) or CRGRIGF-LRTDC (P2) (dash indicates cleavage site) at two crosslink densities. Exogenous MMP-2 degraded P1 and P2 hydrogels similarly. Read More

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http://dx.doi.org/10.1002/bit.26957DOI Listing
February 2019

An X-ray microtomography-based method for detailed analysis of the three-dimensional morphology of fungal pellets.

Biotechnol Bioeng 2019 Feb 15. Epub 2019 Feb 15.

Chair of Process Systems Engineering, Technical University of Munich, Gregor-Mendel Straße 4, 85354 Freising, Germany.

Filamentous fungi are widely used in the production of biotechnological compounds. Since their morphology is strongly linked to productivity, it is a key parameter in industrial biotechnology. However, identifying the morphological properties of filamentous fungi is challenging. Read More

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http://dx.doi.org/10.1002/bit.26956DOI Listing
February 2019

Challenging the workhorse: Comparative analysis of eukaryotic microorganisms for expressing monoclonal antibodies.

Biotechnol Bioeng 2019 Feb 10. Epub 2019 Feb 10.

Biogen, 225 Binney St, Cambridge, Massachusetts, 02142, USA.

For commercial protein therapeutics, Chinese hamster ovary (CHO) cells have an established history of safety, proven capability to express a wide range of therapeutic proteins, and high volumetric productivities. Expanding global markets for therapeutic proteins and increasing concerns for broadened access of these medicines has catalyzed consideration of alternative approaches to this platform. Reaching these objectives likely will require an order of magnitude increase in volumetric productivity and a corresponding reduction in the costs of manufacture. Read More

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http://dx.doi.org/10.1002/bit.26951DOI Listing
February 2019
1 Read

CRISPR-Cas9 nickase-assisted base editing in the solvent producer Clostridium beijerinckii.

Biotechnol Bioeng 2019 Feb 10. Epub 2019 Feb 10.

Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.

Clostridium beijerinckii is a potentially important industrial microorganism as it can synthesize valuable chemicals and fuels from various carbon sources. The establishment of convenient to use, effective gene tools with which the organism can be rapidly modified is essential if its full potential is to be realized. Here, we developed a genomic editing tool (pCBEclos) for use in C. Read More

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http://dx.doi.org/10.1002/bit.26949DOI Listing
February 2019
1 Read

Improving bioreactor production of a recombinant glycoprotein in Escherichia coli: effect of specific growth rate on protein glycosylation and specific productivity.

Biotechnol Bioeng 2019 Feb 10. Epub 2019 Feb 10.

Instituto de Investigaciones Biotecnológicas Dr. Rodolfo A. Ugalde, Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín, CONICET, San Martín, Buenos Aires, Argentina.

In the last decades bacterial glycoengineering emerged as a new field as the result of the ability to transfer the Campylobacter jejuni N-glycosylation machinery into Escherichia coli for the production of recombinant glycoproteins that can be used as antigens for diagnosis, vaccines and therapeutics. However, the identification of critical parameters implicated in the production process and its optimization in order to jump to a productive scale is still required. In this work, we developed a dual expression glycosylation vector for the production of the recombinant glycoprotein AcrA-O157, a novel antigen that allows the serodiagnosis of the infection with enterohemorrhagic Escherichia coli O157 in humans. Read More

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http://dx.doi.org/10.1002/bit.26953DOI Listing
February 2019

Generation and characterization of a functional human adipose-derived multipotent mesenchymal stromal cell line.

Biotechnol Bioeng 2019 Feb 10. Epub 2019 Feb 10.

Institute of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.

Multipotent mesenchymal stromal cells (MSC) and MSC-derived products have emerged as promising therapeutic tools. To fully exploit their potential, further mechanistic studies are still necessary and bioprocessing needs to be optimized, which requires an abundant supply of functional MSC for basic research. To address this need, here we used a novel technology to establish a human adipose-derived MSC line with functional characteristics representative of primary MSC. Read More

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http://dx.doi.org/10.1002/bit.26950DOI Listing
February 2019

An integrated platform for mucin-type o-glycosylation network generation and visualization.

Biotechnol Bioeng 2019 Feb 10. Epub 2019 Feb 10.

Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, USA.

Mucin-type O-glycans have profound effects on the structure and stability of glycoproteins. O-glycans on the cell surface proteins also modulate the cell's interactions with the surrounding environments and other cells. The synthetic pathway of O-glycans involves a large number of enzymes with diverse substrate specificity. Read More

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http://dx.doi.org/10.1002/bit.26952DOI Listing
February 2019

Developing scalable cultivation systems of hepatic spheroids for drug metabolism via genomic and functional analyses.

Biotechnol Bioeng 2019 Feb 9. Epub 2019 Feb 9.

Stem Cell Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Republic of Korea.

Spheroids, a widely used three-dimensional (3D) culture model, are standard in hepatocyte culture as they preserve long-term hepatocyte functionality and enhance survivability. In this study, we investigated the effects of three operation modes in 3D culture - static, orbital shaking, and under vertical bidirectional flow using spheroid forming units (SFUs) - on hepatic differentiation and drug metabolism to propose the best for mass production of functionally enhanced spheroids. Spheroids in SFUs exhibited increased hepatic gene expression, albumin secretion, and cytochrome P450 3A4 (CYP3A4) activity during the differentiation period (12 days). Read More

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http://dx.doi.org/10.1002/bit.26954DOI Listing
February 2019

Modeling, simulations and optimization of smooth muscle cell tissue engineering for the production of vascular grafts.

Biotechnol Bioeng 2019 Feb 9. Epub 2019 Feb 9.

National Physical Laboratory (NPL), Teddington, Middlesex, UK.

The paper presents a transient, continuum, two phase model of the tissue engineering in fibrous scaffolds, including transport equations for the flowing culture medium, nutrient and cell concentration with transverse and in-plane diffusion and cell migration, a novel feature of local in-plane transport across a phenomenological pore and innovative layer-by-layer cell filling approach. The model is successfully validated for the smooth muscle cell (SMC) tissue engineering of a vascular graft using crosslinked, electrospun gelatin fiber scaffolds for both static and dynamic cell culture, the latter in a dynamic bioreactor with a rotating shaft on which the tubular scaffold is attached. Parametric studies evaluate the impact of the scaffold microstructure, cell dynamics, oxygen transport and static or dynamic conditions on the rate and extent of cell proliferation and depth of oxygen accessibility. Read More

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http://dx.doi.org/10.1002/bit.26955DOI Listing
February 2019

Improved CRISPR-Cas12a-assisted one-pot DNA editing method enables seamless DNA editing.

Biotechnol Bioeng 2019 Feb 7. Epub 2019 Feb 7.

Department of Gastroenterology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, China.

As the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a (previously known as Cpf1) system cleaves double-stranded DNA and produces a sticky end, it could serve as a useful tool for DNA assembly/editing. To broaden its application, a variety of engineered FnCas12a proteins are generated with expanded protospacer adjacent motif (PAM) requirements. Two variants (FnCas12a-EP15 and EP16) increased the targeting range of FnCas12a by approximately fourfold. Read More

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http://doi.wiley.com/10.1002/bit.26938
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http://dx.doi.org/10.1002/bit.26938DOI Listing
February 2019
25 Reads
4.126 Impact Factor

Enhancing the functionality of a microscale bioreactor system as an industrial process development tool for mammalian perfusion culture.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.

Without a scale-down model for perfusion, high resource demand makes cell line screening or process development challenging, therefore, potentially successful cell lines or perfusion processes are unrealized and their ability untapped. We present here the refunctioning of a high-capacity microscale system that is typically used in fed-batch process development to allow perfusion operation utilizing in situ gravity settling and automated sampling. In this low resource setting, which involved routine perturbations in mixing, pH and dissolved oxygen concentrations, the specific productivity and the maximum cell concentration were higher than 3. Read More

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http://doi.wiley.com/10.1002/bit.26946
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http://dx.doi.org/10.1002/bit.26946DOI Listing
February 2019
6 Reads

Introducing substrate limitations to overcome catabolite repression in a protease producing Bacillus licheniformis strain using membrane-based fed-batch shake flasks.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany.

To overcome catabolite repression, industrial fermentation processes are usually operated in substrate-limited fed-batch mode. Therefore, the implementation of such an operating mode at small scale is crucial to maintain comparable process conditions. In this work, Bacillus licheniformis, a well-known producer of proteases, was cultivated with carbon (glucose)- and nitrogen (ammonium)-limited fed-batch conditions using the previously introduced membrane-based fed-batch shake flasks. Read More

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http://dx.doi.org/10.1002/bit.26948DOI Listing
February 2019

Deregulation of methanol metabolism reverts transcriptional limitations of recombinant Pichia pastoris (Komagataella spp) with multiple expression cassettes under control of the AOX1 promoter.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

Department of Chemical, Biological and Environmental Engineering, Universitat Autònoma de Barcelona, Catalonia, Spain.

The methanol-regulated alcohol oxidase promoter (P ) of Pichia pastoris (syn. Komagataella spp. ) is one of the strongest promoters for heterologous gene expression. Read More

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http://dx.doi.org/10.1002/bit.26947DOI Listing
February 2019
1 Read

Electron acceptor loadings affect chloroform dechlorination in a hydrogen-based membrane biofilm reactor.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875701, Tempe, AZ, USA.

Chloroform (CF) can undergo reductive dechlorination to dichloromethane, chloromethane, and methane. However, competition for H , the electron-donor substrate, may cause poor dechlorination when multiple electron acceptors are present. Common acceptors in anaerobic environments are nitrate (NO ), sulfate (SO ), and bicarbonate (HCO ). Read More

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http://dx.doi.org/10.1002/bit.26945DOI Listing
February 2019

Streptomycin-induced ribosome engineering complemented with fermentation optimization for enhanced production of 10-membered enediynes tiancimycin-A and tiancimycin-D.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

Xiangya International Academy of Translational Medicine, Central South University, Changsha, China.

Tiancimycins (TNMs) are a group of 10-membered anthraquinone-fused enediynes, newly discovered from Streptomyces sp. CB03234. Among them, TNM-A and TNM-D have exhibited excellent antitumor performances and could be exploited as very promising warheads for the development of anticancer antibody-drug conjugates (ADCs). Read More

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http://dx.doi.org/10.1002/bit.26944DOI Listing
February 2019
4.126 Impact Factor

Quantification of proteomic and metabolic burdens predicts growth retardation and overflow metabolism in recombinant Escherichia coli.

Biotechnol Bioeng 2019 Feb 3. Epub 2019 Feb 3.

Department of Engineering Science, University of Oxford, Oxford, UK.

Escherichia coli has been the host organism most frequently investigated for efficient recombinant protein production. However, the production of a foreign protein in recombinant E. coli often leads to growth deterioration and elevated secretion of acetic acid. Read More

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http://dx.doi.org/10.1002/bit.26943DOI Listing
February 2019

Process monitoring of virus-like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.

Virus-like particles (VLPs) have shown great potential as biopharmaceuticals in the market and in clinics. Nonenveloped, in vivo assembled VLPs are typically disassembled and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At the industrial scale, cross-flow filtration (CFF) is the method of choice for performing reassembly by diafiltration. Read More

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http://dx.doi.org/10.1002/bit.26935DOI Listing
January 2019
2 Reads

Application of a TLR overexpression cell model in pyrogen detection.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Department of Pharmacology, Peking University, Health Science Center, Beijing, China.

Pyrogens are components derived from microorganisms that induce complex inflammatory responses. Current approaches to detect pyrogens are complex and difficult to replicate, thus there is a need for new methods to detect pyrogens. We successfully constructed a pyrogen-sensitive cell model by overexpressing Toll-like receptor (TLR)2, TLR4, MD2, and CD14 in HEK293 cells. Read More

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http://dx.doi.org/10.1002/bit.26936DOI Listing
January 2019
1 Read
4.126 Impact Factor

Nitrous oxide production in autotrophic nitrogen removal granular sludge: A modeling study.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark.

The sustainability of autotrophic granular system performing partial nitritation and anaerobic ammonium oxidation (anammox) for complete nitrogen removal is impaired by the production of nitrous oxide (N O). A systematic analysis of the pathways and affecting parameters is, therefore, required for developing N O mitigation strategies. To this end, a mathematical model capable of describing different N O production pathways was defined in this study by synthesizing relevant mechanisms of ammonium-oxidizing bacteria (AOB), nitrite-oxidizing bacteria, heterotrophic bacteria (HB), and anammox bacteria. Read More

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http://dx.doi.org/10.1002/bit.26937DOI Listing
January 2019

Fine-tuning the (2S)-naringenin synthetic pathway using an iterative high-throughput balancing strategy.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.

Metabolic engineering consistently demands to produce the maximum carbon and energy flux to target chemicals. To balance metabolic flux, gene expression levels of artificially synthesized pathways usually fine-tuned using multimodular optimization strategy. However, forward construction is an engineering conundrum because a vast number of possible pathway combinations need to be constructed and analyzed. Read More

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http://dx.doi.org/10.1002/bit.26941DOI Listing
January 2019
1 Read

Stable recombinant production of codon-scrambled lubricin and mucin in human cells.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States of America.

Widespread therapeutic and commercial interest in recombinant mucin technology has emerged due to the unique ability of mucin glycoproteins to hydrate, protect, and lubricate biological surfaces. However, recombinant production of the large, highly repetitive domains that are characteristic of mucins remains a challenge in bio-manufacturing likely due, at least in part, to the inherent instability of DNA repeats in the cellular genome. To overcome this challenge, we exploit codon redundancy to encode desired mucin polypeptides with minimal nucleotide repetition. Read More

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http://dx.doi.org/10.1002/bit.26940DOI Listing
January 2019
5 Reads

Modulation of the central carbon metabolism of Corynebacterium glutamicum improves malonyl-CoA availability and increases plant polyphenol synthesis.

Biotechnol Bioeng 2019 Jan 26. Epub 2019 Jan 26.

Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, Germany.

In recent years microorganisms have been engineered towards synthesizing interesting plant polyphenols such as flavonoids and stilbenes from glucose. Currently, low endogenous supply of malonyl-CoA, indispensable for plant polyphenol synthesis, impedes high product titers. Usually, limited malonyl-CoA availability during plant polyphenol production is avoided by supplementing fatty acid synthesis-inhibiting antibiotics such as cerulenin, which are known to increase the intracellular malonyl-CoA pool as a side effect. Read More

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http://dx.doi.org/10.1002/bit.26939DOI Listing
January 2019
1 Read

Construction of mini-chemostats for high-throughput strain characterization.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Novo Nordisk Foundation Center for Biosustainability, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.

To achieve large-scale, high-throughput experiments for systems biology research of microorganisms, reliable data from robust cultivation systems are needed. Chemostats are such systems, ensuring reproducibility and quality by providing a stable, well-controlled environment for the cells. However, many of the available chemostat systems require large amounts of media and are complex to set up and expensive to purchase and maintain. Read More

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http://dx.doi.org/10.1002/bit.26931DOI Listing
January 2019
2 Reads

Current achievements in the mechanically pretreated conversion of plant biomass.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Laboratory of Solid State Chemistry, Institute of Solid State Chemistry and Mechanochemistry Russian Academy of Sciences, Novosibirsk, Russia.

At present, "mechanochemistry" is synonymous with "grinding," according to the views of a significant number of scientists and technologists. Often, one comes across the opinion that "the less the particle size, the better." The cases of considering chemical reactions occurring during pretreatment, as well as considering changes in the ultrastructure of cell walls are extremely rare. Read More

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http://dx.doi.org/10.1002/bit.26925DOI Listing
January 2019
2 Reads

Decoupling of recombinant protein production from Escherichia coli cell growth enhances functional expression of plant Leloir glycosyltransferases.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Austrian Centre of Industrial Biotechnology, Graz, Austria.

Sugar nucleotide-dependent (Leloir) glycosyltransferases from plants are important catalysts for the glycosylation of small molecules and natural products. Limitations on their applicability for biocatalytic synthesis arise because of low protein expression (≤10 mg/L culture) in standard microbial hosts. Here, we showed two representative glycosyltransferases: sucrose synthase from soybean and UGT71A15 from apple. Read More

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http://dx.doi.org/10.1002/bit.26934DOI Listing
January 2019
7 Reads

Generation of Site-Distinct N-Glycan Variants for In-Vitro Bioactivity Testing.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Merck Biopharma, Biotech Process Sciences, Fenil-sur-Corsier, Switzerland.

Glycosylation, a critical product quality attribute, may affect efficacy and safety of therapeutic proteins in vivo. Chinese hamster ovary (CHO) fed-batch cell culture batches yielded consistent glycoprofiles of a Fc-fusion antibody comprizing three different N-glycosylation sites. By adding media supplements at specific concentrations in cell culture and applying enzymatic glycoengineering, a diverse N-glycan variant population was generated, including high mannose, afucosylated, fucosylated, agalactosylated, galactosylated, asialylated and sialylated forms. Read More

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http://dx.doi.org/10.1002/bit.26930DOI Listing
January 2019
7 Reads

Unveiling the molecular crosstalk in a human induced pluripotent stem cell-derived cardiac model.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Animal Cell Technology Unit, iBET-Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.

In vitro cell-based models that better mimic the human heart tissue are of utmost importance for drug development and cardiotoxicity testing but also as tools to understand mechanisms related with heart disease at cellular and molecular level. Besides, the implementation of analytical tools that allow the depiction and comprehensive understanding of the molecular mechanisms of the crosstalk between the different cell types is also relevant. In this work, we implemented a human cardiac tissue-like in vitro model, derived from human-induced pluripotent stem cell (hiPSC), and evaluated the relevance of the cell-cell communication between the two of the most representative cell populations of the human heart: cardiomyocytes (hiPSC-CM) and endothelial cells (hiPSC-EC). Read More

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http://dx.doi.org/10.1002/bit.26929DOI Listing
January 2019
2 Reads

Potential regulates metabolism and extracellular respiration of electroactive Geobacter biofilm.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Department of Applied Chemistry, University of Science and Technology of China, Hefei, China.

Dissimilatory metal reducer Geobacter sulfurreducens can mediate redox processes through extracellular electron transfer and exhibit potential-dependent electrochemical activity in biofilm. Understanding the microbial acclimation to potential is of critical importance for developing robust electrochemically active biofilms and facilitating their environmental, geochemical, and energy applications. In this study, the metabolism and redox conduction behaviors of G. Read More

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http://doi.wiley.com/10.1002/bit.26928
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http://dx.doi.org/10.1002/bit.26928DOI Listing
January 2019
6 Reads
4.126 Impact Factor

Perfusion cultures require optimum respiratory ATP supply to maximize cell-specific and volumetric productivities.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany.

Perfusion processes are an emerging alternative to common fed-batch processes in the growing biopharmaceutical industry. However, the challenge of maintaining high cell-specific productivities remains. In this study, glucose limitation was applied to two perfusion steady states and compared with a third steady state without any detectable limitation. Read More

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http://dx.doi.org/10.1002/bit.26926DOI Listing
January 2019
2 Reads

Engineering Escherichia coli as a platform for the in vivo synthesis of prenylated aromatics.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas.

Prenylated aromatics (PAs) are an important class of natural products with valuable pharmaceutical applications. To address current limitations of their sourcing from plants, here, we present a microbial platform for the in vivo synthesis of PAs based on the aromatic prenyltransferase NphB from Streptomyces sp. strain CL190. Read More

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http://doi.wiley.com/10.1002/bit.26932
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http://dx.doi.org/10.1002/bit.26932DOI Listing
January 2019
4 Reads

Engineering the migration and attachment behaviour of primary dermal fibroblasts.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

Smart Matrix Limited, Mount Vernon Hospital, Northwood, UK.

The availability of primary cells present in pathological conditions is often very limited due to stringent ethical regulation and patient consent. One such condition is chronic wounds, where dermal fibroblasts show a deficient migration. In vitro models with cellular tools that mimic the in vivo scenario would be advantageous to test new therapies for these challenging wounds. Read More

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http://dx.doi.org/10.1002/bit.26927DOI Listing
January 2019
2 Reads

Local direction change of surface gliding microtubules.

Biotechnol Bioeng 2019 Jan 19. Epub 2019 Jan 19.

School of Mechanical Engineering, Purdue University, West Lafayette, Indiana.

In vitro gliding assay, microtubule translocation by kinesin motor proteins on a surface, has been used as an engineering tool in analyte detection, molecular cargo transport, and other applications. Although controlling the moving direction is often necessary to realize these applications, current direction control methods focus largely on lithographic microfabrication of tracks or external fields on the microtubules. These methods are effective, but are relatively complicated. Read More

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http://dx.doi.org/10.1002/bit.26933DOI Listing
January 2019
1 Read

Combining orthogonal CRISPR and CRISPRi systems for genome engineering and metabolic pathway modulation in Escherichia coli.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan.

CRISPR utilizing Cas9 from Streptococcus pyogenes (SpCas9) and CRISPR interference (CRISPRi) employing catalytically inactive SpCas9 (SpdCas9) have gained popularity for Escherichia coli engineering. To integrate the SpdCas9-based CRISPRi module using CRISPR while avoiding mutual interference between SpCas9/SpdCas9 and their cognate single-guide RNA (sgRNA), this study aimed at exploring an alternative Cas nuclease orthogonal to SpCas9. We compared several Cas9 variants from different microorganisms such as Staphylococcus aureus (SaCas9) and Streptococcus thermophilius CRISPR1 (St1Cas9) as well as Cas12a derived from Francisella novicida (FnCas12a). Read More

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http://doi.wiley.com/10.1002/bit.26915
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http://dx.doi.org/10.1002/bit.26915DOI Listing
January 2019
6 Reads

Distinct timescales of RNA regulators enable the construction of a genetic pulse generator.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Mechanical Engineering, University of California at Riverside, Riverside, California.

To build complex genetic networks with predictable behaviors, synthetic biologists use libraries of modular parts that can be characterized in isolation and assembled together to create programmable higher-order functions. Characterization experiments and computational models for gene regulatory parts operating in isolation are routinely used to predict the dynamics of interconnected parts and guide the construction of new synthetic devices. Here, we individually characterize two modes of RNA-based transcriptional regulation, using small transcription activating RNAs (STARs) and clustered regularly interspaced short palindromic repeats interference (CRISPRi), and show how their distinct regulatory timescales can be used to engineer a composed feedforward loop that creates a pulse of gene expression. Read More

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http://doi.wiley.com/10.1002/bit.26918
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http://dx.doi.org/10.1002/bit.26918DOI Listing
January 2019
6 Reads

Control of IgG glycosylation by in situ and real-time estimation of specific growth rate of CHO cells cultured in bioreactor.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Laboratoire Réactions et Génie des Procédés, Université de Lorraine, CNRS, LRGP, Vandœuvre-lès-Nancy, France.

The cell-specific growth rate (µ) is a critical process parameter for antibody production processes performed by animal cell cultures, as it describes the cell growth and reflects the cell physiological state. When there are changes in these parameters, which are indicated by variations of µ, the synthesis and the quality of antibodies are often affected. Therefore, it is essential to monitor and control the variations of µto assure the antibody production and achieve high product quality. Read More

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http://dx.doi.org/10.1002/bit.26914DOI Listing
January 2019
2 Reads

Three-dimensional spherical gelatin bubble-based scaffold improves the myotube formation of H9c2 myoblasts.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan.

Microenvironmental factors including physical and chemical cues can regulate stem cells as well as terminally differentiated cells to modulate their biological function and differentiation. However, one of the physical cues, the substrate's dimensionality, has not been studied extensively. In this study, the flow-focusing method with a microfluidic device was used to generate gelatin bubbles to fabricate highly ordered three-dimensional (3D) scaffolds. Read More

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http://doi.wiley.com/10.1002/bit.26917
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http://dx.doi.org/10.1002/bit.26917DOI Listing
January 2019
5 Reads

Mucin-coating technologies for protection and reduced aggregation of cellular production systems.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York.

Optimization of host-cell production systems with improved yield and production reliability is desired to meet the increasing demand for biologics with complex posttranslational modifications. Aggregation of suspension-adapted mammalian cells remains a significant problem that can limit the cellular density and per volume yield of bioreactors. Here, we propose a genetically encoded technology that directs the synthesis of antiadhesive and protective coatings on the cellular surface. Read More

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http://dx.doi.org/10.1002/bit.26916DOI Listing
January 2019
2 Reads

Analysis of Golgi pH in Chinese hamster ovary cells using ratiometric pH-sensitive fluorescent proteins.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Biological Sciences, KAIST, Daejeon, Republic of Korea.

Acidic Golgi pH plays an important role in protein glycosylation, one of the critical quality attributes of therapeutic proteins. To determine the intracellular Golgi pH during culture, stable Chinese hamster ovary (CHO) cell clones expressing pHluorin2, a ratiometric pH-sensitive fluorescent protein (FP), in the cis- and trans-Golgi, were constructed by fusing pHluorin2 with specific targeting proteins, acetylglucosaminyltransferase, and a galactosyltransferase, respectively. Stable CHO cell clones expressing pHluorin2 in the cytoplasm were also constructed. Read More

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http://doi.wiley.com/10.1002/bit.26920
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http://dx.doi.org/10.1002/bit.26920DOI Listing
January 2019
12 Reads
4.126 Impact Factor

In vitro vascularized liver and tumor tissue microenvironments on a chip for dynamic determination of nanoparticle transport and toxicity.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas.

This paper presents the development of a vascularized breast tumor and healthy or tumorigenic liver microenvironments-on-a-chip connected in series. This is the first description of a vascularized multi tissue-on-a-chip microenvironment for modeling cancerous breast and cancerous/healthy liver microenvironments, to allow for the study of dynamic and spatial transport of particles. This device enables the dynamic determination of vessel permeability, the measurement of drug and nanoparticle transport, and the assessment of the associated efficacy and toxicity to the liver. Read More

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http://dx.doi.org/10.1002/bit.26919DOI Listing
January 2019
2 Reads

The role of assembly parameters on polyplex poly(beta-amino ester) nanoparticle transfections.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Intracellular delivery of nucleic acids to mammalian cells using polyplex nanoparticles (NPs) remains a challenge both in vitro and in vivo, with transfections often suffering from variable efficacy. To improve reproducibility and efficacy of transfections in vitro using a next-generation polyplex transfection material poly(beta-amino ester)s (PBAEs), the influence of multiple variables in the preparation of these NPs on their transfection efficacy was explored. The results indicate that even though PBAE/pDNA polyplex NPs are formed by the self-assembly of polyelectrolytes, their transfection is not affected by the manner in which the components are mixed, facilitating self-assembly in a single step, but timing for self-assembly of 5-20 min is optimal. Read More

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http://dx.doi.org/10.1002/bit.26921DOI Listing
January 2019
2 Reads

Continuous integrated antibody precipitation with two-stage tangential flow microfiltration enables constant mass flow.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Biotechnology, University of Natural Resources and Life Sciences,, Vienna, Austria.

Continuous precipitation is a new unit operation for the continuous capture of antibodies. The capture step is based on continuous precipitation with PEG6000 and Zn in a tubular reactor integrated with a two-stage continuous tangential flow filtration unit. The precipitate cannot be separated with centrifugation, because a highly compressed sediment results in poor resolubilization. Read More

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http://dx.doi.org/10.1002/bit.26922DOI Listing
January 2019
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Constitutively solvent-tolerant Pseudomonas taiwanensis VLB120∆ C∆ ttgV supports particularly high-styrene epoxidation activities when grown under glucose excess conditions.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH-UFZ, Leipzig, Germany.

Solvent-tolerant bacteria represent an interesting option to deal with the substrate and product toxicity in bioprocesses. Recently, constitutive solvent tolerance was achieved for Pseudomonas taiwanensis VLB120 via knockout of the regulator TtgV, making tedious adaptation unnecessary. Remarkably, ttgV knockout increased styrene epoxidation activities of P. Read More

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http://dx.doi.org/10.1002/bit.26924DOI Listing
January 2019
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Effect of precise control of flux ratio between the glycolytic pathways on mevalonate production in Escherichia coli.

Biotechnol Bioeng 2019 Jan 13. Epub 2019 Jan 13.

Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan.

Mevalonate is a useful metabolite synthesized from three molecules of acetyl-CoA, consuming two molecules of NADPH. Escherichia coli ( E. coli) catabolizes glucose to acetyl-CoA via several routes, such as the Embden-Meyerhof-Parnas (EMP) and the oxidative pentose phosphate (oxPP) pathways. Read More

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http://dx.doi.org/10.1002/bit.26923DOI Listing
January 2019
2 Reads

Synthetic biology for bioengineering virus-like particle vaccines.

Biotechnol Bioeng 2018 Dec 31. Epub 2018 Dec 31.

The University of Queensland, St Lucia, Queensland, Australia.

Vaccination is the most effective method of disease prevention and control. Many viruses and bacteria that once caused catastrophic pandemics (e.g. Read More

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http://dx.doi.org/10.1002/bit.26890DOI Listing
December 2018
3 Reads

Interaction of cell culture process parameters for modulating mAb afucosylation.

Biotechnol Bioeng 2018 Dec 29. Epub 2018 Dec 29.

Cell Culture, PTD, Genentech, South San Francisco, California.

The extent of afucosylation, which refers to the absence of core fucose on Fc glycans, can correlate positively with the antibody-dependent cellular cytotoxicity (ADCC) activity of a monoclonal antibody (mAb). Therefore, it is important to maintain consistent afucosylation during cell culture process scale-up in bioreactors for a mAb with ADCC activity. However, there is currently a lack of understanding about the impact of partial pressure of carbon dioxide (pCO )-a parameter that can vary with bioreactor scale-on afucosylation. Read More

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http://dx.doi.org/10.1002/bit.26908DOI Listing
December 2018
2 Reads

L-Fucose production by engineered Escherichia coli.

Biotechnol Bioeng 2018 Dec 29. Epub 2018 Dec 29.

Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.

L-Fucose (6-deoxy-L-galactose) is a major constituent of glycans and glycolipids in mammals. Fucosylation of glycans can confer unique functional properties and may be an economical way to manufacture L-fucose. Research can extract L-fucose directly from brown algae, or by enzymatic hydrolysis of L-fucose-rich microbial exopolysaccharides. Read More

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http://dx.doi.org/10.1002/bit.26907DOI Listing
December 2018
3 Reads

Determination of critical shear stress for maturation of human pluripotent stem cell-derived endothelial cells towards an arterial subtype.

Biotechnol Bioeng 2018 Dec 29. Epub 2018 Dec 29.

Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.

Human pluripotent stem cell-derived endothelial cells (hPSC-ECs) present an attractive alternative to primary EC sources for vascular grafting. However, there is a need to mature them towards either an arterial or venous subtype. A vital environmental factor involved in the arteriovenous specification of ECs during early embryonic development is fluid shear stress; therefore, there have been attempts to employ adult arterial shear stress conditions to mature hPSC-ECs. Read More

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http://dx.doi.org/10.1002/bit.26910DOI Listing
December 2018
2 Reads
4.126 Impact Factor

Development of food-grade expression system for d-allulose 3-epimerase preparation with tandem isoenzyme genes in Corynebacterium glutamicum and its application in conversion of cane molasses to D-allulose.

Biotechnol Bioeng 2018 Dec 29. Epub 2018 Dec 29.

National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.

D-Allulose 3-epimerase (DAE) has been applied to produce D-allulose, a low-calorie and functional sweetener. In this study, a new DAE from Paenibacillus senegalensis was characterized in Escherichia coli. Furthermore, we presented a tandem isoenzyme gene expression strategy to express multiple DAEs in one cell and construct food-grade expression systems based on Corynebacterium glutamicum. Read More

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http://doi.wiley.com/10.1002/bit.26909
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http://dx.doi.org/10.1002/bit.26909DOI Listing
December 2018
5 Reads

Rapid prototyping of proteins: Mail order gene fragments to assayable proteins within 24 hours.

Biotechnol Bioeng 2019 Mar 16;116(3):667-676. Epub 2019 Jan 16.

Iowa State University Chemical and Biological Engineering, Ames, Iowa.

In this study, we present a minimal template design and accompanying methods to produce assayable quantities of custom sequence proteins within 24 hr from receipt of inexpensive gene fragments from a DNA synthesis vendor. This is done without the conventional steps of plasmid cloning or cell-based amplification and expression. Instead the linear template is PCR amplified, circularized, and isothermally amplified using a rolling circle polymerase. Read More

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http://dx.doi.org/10.1002/bit.26912DOI Listing
March 2019
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Extracellular hemoglobin combined with an O -generating material overcomes O limitation in the bioartificial pancreas.

Biotechnol Bioeng 2018 Dec 29. Epub 2018 Dec 29.

Immuno-Endocrinology Unit (IECM), Oniris, INRA, Université Bretagne Loire, Nantes, France.

The bioartificial pancreas encapsulating pancreatic islets in immunoprotective hydrogel is a promising therapy for Type 1 diabetes. As pancreatic islets are highly metabolically active and exquisitely sensitive to hypoxia, maintaining O supply after transplantation remains a major challenge. In this study, we address the O limitation by combining silicone-encapsulated CaO (silicone-CaO ) to generate O with an extracellular hemoglobin O -carrier coencapsulated with islets. Read More

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http://dx.doi.org/10.1002/bit.26913DOI Listing
December 2018
6 Reads