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Biotechnology and Bioengineering

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https://www.readbyqxmd.com/read/27922181/evaluation-of-gas-and-carbon-transport-in-a-methanogenic-bioelectrochemical-system-bes
#1
Christy M Dykstra, Spyros G Pavlostathis
Bioelectrochemical systems (BESs) may be used to upgrade anaerobic digester biogas by directly converting CO2 to CH4 .The objective of this study was to evaluate gas (N2 , CO2 , CH4 , and H2 ) and carbon transport within a methanogenic BES. Four BES configurations were evaluated: abiotic anode with abiotic cathode (AAn-ACa), bioanode with abiotic cathode (BAn-ACa), abiotic anode with biocathode (AAn-BCa), and bioanode with biocathode (BAn-BCa). Transport of N2 , a gas commonly used for flushing anoxic systems, out of the anode headspace ranged from 3...
December 6, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27922179/a-carbon-dioxide-stripping-model-for-mammalian-cell-culture-in-manufacturing-scale-bioreactors
#2
Zizhuo Xing, Amanda M Lewis, Michael C Borys, Zheng Jian Li
Control of carbon dioxide within the optimum range is important in mammalian bioprocesses at the manufacturing scale in order to ensure robust cell growth, high protein yields, and consistent quality attributes. The majority of bioprocess development work is done in laboratory bioreactors, in which carbon dioxide levels are more easily controlled. Some challenges in carbon dioxide control can present themselves when cell culture processes are scaled up, because carbon dioxide accumulation is a common feature due to longer gas-residence time of mammalian cell culture in large scale bioreactors...
December 6, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27922175/a-framework-to-quantify-karyotype-variation-associated-with-cho-production-instability
#3
Jong Youn Baik, Kelvin H Lee
Chinese hamster ovary (CHO) cells, major mammalian host cells for biomanufacturing of therapeutic proteins, have been extensively investigated to enhance productivity and product quality. However, cell line instability resulting in unexpected changes in productivity or product quality is challenging for biomanufacturing. Based on previous reports about causes and characteristics of production instability, we hypothesized that chromosomal rearrangements due to genomic instability are associated with production instability...
December 6, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27888663/effect-of-structural-carbohydrates-and-lignin-content-on-the-anaerobic-digestion-of-paper-and-paper-board-materials-by-anaerobic-granular-sludge
#4
Jorge Gonzalez-Estrella, Caitlin M Asato, Amber C Jerke, James J Stone, Patrick C Gilcrease
Anaerobic digestion (AD) of lignocellulosic materials is commonly limited by the hydrolysis step. Unlike unprocessed lignocellulosic materials, paper and paper board (PPB) are processed for their fabrication. Such modifications may affect their methane yields and methane production rates. Previous studies have investigated the correlation between lignin and biomethane yields of unprocessed lignocellulosic materials; nevertheless, there is limited knowledge regarding the relationship between the AD kinetic parameters and composition of PPB...
November 26, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27888662/toward-high-solids-loading-process-for-lignocellulosic-biofuel-production-at-a-low-cost
#5
Mingjie Jin, Cory Sarks, Bryan D Bals, Nick Posawatz, Christa Gunawan, Bruce E Dale, Venkatesh Balan
High solids loadings (>18 wt%) in enzymatic hydrolysis and fermentation are desired for lignocellulosic biofuel production at a high titer and low cost. However, sugar conversion and ethanol yield decrease with increasing solids loading. The factor(s) limiting sugar conversion at high solids loading is not clearly understood. In the present study, we investigated the effect of solids loading on simultaneous saccharification and co-fermentation (SSCF) of AFEX(TM) (ammonia fiber expansion) pretreated corn stover for ethanol production using a xylose fermenting strain Saccharomyces cerevisiae 424A(LNH-ST)...
November 26, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27882539/in-vitro-suppression-of-two-different-stop-codons
#6
Eden Ozer, Yonatan Chemla, Orr Schlesinger, Haim Yuval Aviram, Inbal Riven, Gilad Haran, Lital Alfonta
Proteins play a crucial role in all living organisms, with the twenty natural amino acids as their building blocks. Unnatural amino acids are synthetic derivatives of these natural building blocks. These amino acids have unique chemical or physical properties as a result of their specific side chain residues. Their incorporation into proteins through ribosomal translation in response to one of the stop codons has opened a new way to manipulate and study proteins by enabling new functionalities, thus expending the genetic code...
November 24, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27869295/-noninvasive-assessment-of-tissue-engineered-graft-viability-by-oxygen-17-magnetic-resonance-spectroscopy
#7
Samuel A Einstein, Bradley P Weegman, Jennifer P Kitzmann, Klearchos K Papas, Michael Garwood
Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy ((17) O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with (17) O2 can also enable measurements of TEG viability...
November 21, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27869294/enhancement-of-human-neural-stem-cell-self-renewal-in-3d-hypoxic-culture
#8
Sasan Sharee Ghourichaee, Elizabeth M Powell, Jennie B Leach
The pathology of neurological disorders is associated with the loss of neuronal and glial cells that results in functional impairments. Human neural stem cells (hNSCs), due to their self-renewing and multipotent characteristics, possess enormous tissue-specific regenerative potential. However, the efficacy of clinical applications is restricted due to the lack of standardized in vitro cell production methods with the capability of generating hNSC populations with well-defined cellular compositions. At any point, a population of hNSCs may include undifferentiated stem cells, intermediate and terminally differentiated progenies, and dead cells...
November 21, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27869292/model-based-investigation-of-intracellular-processes-determining-antibody-fc-glycosylation-under-mild-hypothermia
#9
Si Nga Sou, Philip M Jedrzejewski, Ken Lee, Christopher Sellick, Karen M Polizzi, Cleo Kontoravdi
Despite the positive effects of mild hypothermic conditions on monoclonal antibody (mAb) productivity (qmAb ) during mammalian cell culture, the impact of reduced culture temperature on mAb Fc-glycosylation and the mechanism behind changes in the glycan composition is not fully established. The lack of knowledge about the regulation of dynamic intracellular processes under mild hypothermia restricts bioprocess optimisation. To address this issue, a mathematical model that quantitatively describes CHO cell behaviour and metabolism, mAb synthesis and its N-linked glycosylation profiles before and after the induction of mild hypothermia is constructed using two sets of parameters...
November 21, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27869289/integration-of-parallel-13-c-labeling-experiments-and-in-silico-pathway-analysis-for-enhanced-production-of-ascomycin
#10
Haishan Qi, Mengmeng Lv, Kejing Song, Jianping Wen
Herein, the hyper-producing strain for ascomycin was engineered based on (13) C-labeling experiments and elementary flux modes analysis (EFMA). First, the metabolism of non-model organism Streptomyces hygroscopicus var. ascomyceticus SA68 was investigated and an updated network model was reconstructed using (13) C- metabolic flux analysis. Based on the precise model, EFMA was further employed to predict genetic targets for higher ascomycin production. Chorismatase (FkbO) and pyruvate carboxylase (Pyc) were predicted as the promising overexpression and deletion targets, respectively...
November 21, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27858993/challenges-in-engineering-large-customized-bone-constructs
#11
REVIEW
David P Forrestal, Travis J Klein, Maria A Woodruff
The ability to treat large tissue defects with customized, patient-specific scaffolds is one of the most exciting applications in the tissue engineering field. While an increasing number of modestly sized tissue engineering solutions are making the transition to clinical use, successfully scaling up to large scaffolds with customized geometry is proving to be a considerable challenge. Managing often conflicting requirements of cell placement, structural integrity and a hydrodynamic environment supportive of cell culture throughout the entire thickness of the scaffold has driven the continued development of many techniques used in the production, culturing and characterization of these scaffolds...
November 18, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861744/omega-3-production-by-fermentation-of-yarrowia-lipolytica-from-fed-batch-to-continuous
#12
Dongming Xie, Edward Miller, Pamela Sharpe, Ethel Jackson, Quinn Zhu
The omega-3 fatty acid, cis-5,8,11,14,17-eicosapentaenoic acid (C20:5; EPA) has wide-ranging benefits in improving heart health, immune function, and mental health. A sustainable source of EPA production through fermentation of metabolically engineered Yarrowia lipolytica has been developed. In this paper, key fed-batch fermentation conditions were identified to achieve 25% EPA in the yeast biomass, which is so far the highest EPA titer reported in the literature. Dynamic models of the EPA fermentation process were established for analyzing, optimizing, and scaling up the fermentation process...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861738/online-measurement-of-viscosity-for-biological-systems-in-stirred-tank-bioreactors
#13
Maximilian Schelden, William Lima, Eric Will Doerr, Martin Wunderlich, Lars Rehmann, Jochen Büchs, Lars Regestein
One of the most critical parameters in chemical and biochemical processes is the viscosity of the medium. Its impact on mixing, as well as on mass and energy transfer is substantial. An increase of viscosity with reaction time can be caused by the formation of biopolymers like xanthan or by filamentous growth of microorganisms. In either case the properties of fermentation broth are changing and frequently non-Newtonian behavior are observed, resulting in major challenges for the measurement and control of mixing and mass transfer...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861737/novel-technique-for-high-throughput-measurement-of-active-monooxygenase-concentration
#14
Tim Welters, Thomas Horn, Anna Joelle Ruff, Ulrich Schwaneberg, Jochen Büchs
Absorbance measurements via transmitting light spectroscopy in microtiter plates are established for high throughput screening of biological systems. These measurements allow for the determination of important process parameters within a short time. However, absorbance determination via transmitted light measurements is not always feasible. As for carbon monoxide difference absorbance spectroscopy, used for concentration measurements of active P450 monooxygenases (P450s), security standards, and consistent gassing have to be addressed...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861733/multiplex-growth-rate-phenotyping-of-synthetic-mutants-in-selection-to-engineer-glucose-and-xylose-co-utilization-in-escherichia-coli
#15
A J Groot, S C Cepress-Mclean, A Robbins-Pianka, R Knight, R T Gill
Engineering the simultaneous consumption of glucose and xylose sugars is critical to enable the sustainable production of biofuels from cellulosic biomass. In most major industrial microorganisms glucose completely inhibits the uptake of xylose, limiting efficient sugar mixture conversion. In E.coli removal of the major glucose transporter PTS allows for glucose and xylose co-consumption but only after prolonged adaptation, which is an effective process but hard to control and prone to co-evolving undesired traits...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861732/shuttle-mediated-nanoparticle-transport-across-an-in-vitro-brain-endothelium-under-flow-conditions
#16
Andrea P Falanga, Gabriele Pitingolo, Maurizio Celentano, Armando Cosentino, Pietro Melone, Raffaele Vecchione, Daniela Guarnieri, Paolo A Netti
The blood brain barrier (BBB) represents a challenge in the development of new nano-delivery systems able to reach the central nervous system (CNS). In order to test the efficacy of these nanocarriers, it is fundamental to use in vitro models that resemble the in vivo cell culture conditions. Here, we demonstrate for the first time the ability of a membranotropic peptide, namely gH625, to transport a cargo -acting as a shuttle- across the BBB layer under flow conditions that mimic the blood flow rate. To this aim, a BBB microfluidic device was designed based on a transparent polyester porous membrane sandwiched between a top and a bottom overlying channel made of poly(methyl methacrylate) (PMMA)...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27861731/identification-of-mineral-binding-peptides-that-discriminate-between-chalcopyrite-and-enargite
#17
Susan Curtis, Franziska L Lederer, W Scott Dunbar, Ross T A MacGillivray
Innovative approaches to the separation of minerals and subsequent extraction of metals are imperative owing to the increasing mineralogical complexity of ore deposits that are difficult or even impossible to separate into slurries or solutions containing only the minerals or metals of interest. Low recovery of metal is typical for these complex deposits leading to significant losses to tailings. In addition, the minerals often contain impurities, some toxic, which are difficult and costly to control or manage during the processing of a concentrate or other mineral product...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27858995/establishing-very-long-chain-fatty-alcohol-and-wax-ester-biosynthesis-in-saccharomyces-cerevisiae
#18
Leonie Wenning, Tao Yu, Florian David, Jens Nielsen, Verena Siewers
Wax esters (WEs) are neutral lipids and can be used for a broad range of commercial applications, including personal care products, lubricants, or coatings. They are synthesized by enzymatic reactions catalyzed by a fatty acyl reductase (FAR) and a wax ester synthase (WS). At present, commercially used WEs are mainly isolated from Simmondsia chinensis (jojoba), but the high extraction costs and limited harvest areas constrain their use. The use of FARs in combination with different WSs to achieve a synthesis of jojoba-like WEs in bacteria and yeast has been reported previously, but the products were restricted to C28-C36 WEs...
November 14, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27883174/maximization-of-cell-viability-rather-than-biocatalyst-activity-improves-whole-cell-%C3%AF-oxyfunctionalization-performance
#19
Marvin Kadisch, Mattijs K Julsing, Manfred Schrewe, Nico Jehmlich, Benjamin Scheer, Martin von Bergen, Andreas Schmid, Bruno Bühler
It is a common misconception in whole-cell biocatalysis to refer to an enzyme as the biocatalyst, thereby neglecting the structural and metabolic framework provided by the cell. Here, the low whole-cell biocatalyst stability, that is, the stability of specific biocatalyst activity, in a process for the terminal oxyfunctionalization of renewable fatty acid methyl esters was investigated. This reaction, which is difficult to achieve by chemical means, is catalyzed by Escherichia coli featuring the monooxygenase system AlkBGT and the uptake facilitator AlkL from Pseudomonas putida GPo1...
November 7, 2016: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/27869299/anaerobic-reduction-of-2-6-dinitrotoluene-by-shewanella-oneidensis-mr-1-roles-of-mtr-respiratory-pathway-and-nfnb
#20
Dong-Feng Liu, Di Min, Lei Cheng, Feng Zhang, Dao-Bo Li, Xiang Xiao, Guo-Ping Sheng, Han-Qing Yu
Dinitrotoluene (DNT) is a widely present pollutant in aquatic environments, and its biodegradation is an economically attractive way to effectively removal. In aquatic environments, the presence of electrochemically active bacteria (EAB) could contribute to the anaerobic bioreduction of DNT. However, the mechanism behind such a biodegradation process at gene level remains to be further elucidated. In this work, the anaerobic reduction of 2,6-dinitrotoluene (2,6-DNT) by Shewanella oneidensis MR-1, a typical EAB in aquatic environments, was investigated...
November 7, 2016: Biotechnology and Bioengineering
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