scholarly journals Process Evaluation of Recombinant Chitin Deacetylase Expression in E. Coli Rosetta pLysS Cells using Statistical Design of Experiments

2021 ◽  
Author(s):  
Goutam Mohan Pawaskar ◽  
Ritu Raval ◽  
Subbalaxmi S
Keyword(s):  
Large Scale ◽  
Statistical Design ◽  
Fold Increase ◽  
Process Conditions ◽  
Scale Production ◽  
Statistical Design Of Experiments ◽  
Chitin Deacetylase ◽  
E Coli ◽  
Nutritional Conditions ◽  
Wide Range

Abstract Chitin is a natural polymer with N-acetylglucosamine units, extracted from seafood waste as a major source. It remains an underexplored polymer due to its crystalline structure. The commercial applicability can be improved if we could make it soluble. One of the routes employed to decrease this crystallinity is the conversion of chitin to chitosan via deacetylation. The industrial production of chitosan uses chemical methods, which leaves the process footprint on the environment. The greener alternative approach to producing chitosan is using chitin deacetylases (CDA). The enzymatically converted chitosan with known characteristics has a wide range of applications, importantly in the biomedical field. In the present paper, we report heterologous expression of CDA from a marine moneran; Bacillus aryabhattai B8W22. The process and the nutritional conditions were optimized for the submerged fermentation condition of E. coli Rosetta pLysS expressing the recombinant CDA using the design of experiment tools. The employment of central composite design (CCD) resulted in a ~2.39 fold increase in the total activity of expressed CDA with the process conditions of induction temperature at 22 ºC, agitation at 120 rpm, and 30 h of fermentation. The nutritional conditions required for the optimized expression were 0.061% glucose concentration and 1% lactose in media. The employment of these optimal growth conditions could result in cost-effective large-scale production of the lesser-explored moneran deacetylase, embarking on the greener route to produce biomedical grade chitosan.

Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1362-1363
Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Large Scale ◽  
Hexagonal Phase ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Process Conditions ◽  
Tin Films ◽  
Wide Range ◽  
Fcc Phase ◽  
Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

scholarly journals Xylanolytic Bacillus species for xylooligosaccharides production: a critical review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Rozina Rashid ◽  
Muhammad Sohail
Keyword(s):  
Large Scale ◽  
Extracellular Enzymes ◽  
Membrane Separation ◽  
Well Being ◽  
Bacillus Species ◽  
Scale Production ◽  
Food Ingredients ◽  
Large Scale Production ◽  
Wide Range ◽  
Biological Impacts

AbstractThe capacity of different Bacillus species to produce large amounts of extracellular enzymes and ability to ferment various substrates at a wide range of pH and temperature has placed them among the most promising hosts for the industrial production of many improved and novel products. The global interest in prebiotics, for example, xylooligosaccharides (XOs) is ever increasing, rousing the quest for various forms with expanded productivity. This article provides an overview of xylanase producing bacilli, with more emphasis on their capacity to be used in the production of the XOs, followed by the purification strategies, characteristics and application of XOs from bacilli. The large-scale production of XOs is carried out from a number of xylan-rich lignocellulosic materials by chemical or enzymatic hydrolysis followed by purification through chromatography, vacuum evaporation, solvent extraction or membrane separation methods. Utilization of XOs in the production of functional products as food ingredients brings well-being to individuals by improving defense system and eliminating pathogens. In addition to the effects related to health, a variety of other biological impacts have also been discussed.

scholarly journals Cloning, expression, and analysis of the group 2 allergen from Dermatophagoides farinae from China

2010 ◽  
Vol 82 (4) ◽  
pp. 941-951 ◽  
Author(s):  
Cui Yu-bao ◽  
Ying Zhou ◽  
Shi Weihong ◽  
Ma Guifang ◽  
Li Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Alpha Helix ◽  
Random Coil ◽  
Reference Sequence ◽  
Scale Production ◽  
Dermatophagoides Farinae ◽  
E Coli ◽  
Large Scale Production ◽  
Solid Foundation ◽  
Group 2

To obtain the recombinant group 2 allergen product of Dermatophagoides farinae (Der f 2), the Der f 2 gene was synthesized by RT-PCR. The full-length cDNA comprised 441 nucleotides and was 99.3% identical to the reference sequence (GenBank AB195580). The cDNA was bound to vector pET28a to construct plasmid pET28a(+)-Der f 2, which was transformed into E. coli BL21 and induced by IPTG. SDS-PAGE showed a specific band of about 14kDa in the hole cell lysate. s estiated by chroatography, about 3.86 g of the recobinant product as obtained, which conjugated with serum IgE from asthmatic children. The protein had a signal peptide of 17 amino acids. Its secondary structure comprised an alpha helix (19.86%), an extended strand (30.82%), and a random coil (49.32%). The subcellular localization of this allergen was predicted to be at mitochondria. Furthermore, its function was shown to be associated with an MD-2-related lipid-recognition (ML) domain. The results of this study provide a solid foundation for large-scale production of the allergen for clinical diagnosis and treatent of allergic disorders.

Statistical Optimization of HVAF Sprayed Cr3C2-NiCr Coatings for Minimizing Decarburization

2000 ◽  
Author(s):  
S.J. Matthews ◽  
M.M. Hyland
Keyword(s):  
Factorial Design ◽  
Statistical Design ◽  
Process Variable ◽  
Traverse Speed ◽  
Deposition Efficiency ◽  
Spray Parameters ◽  
Statistical Design Of Experiments ◽  
Spray Coatings ◽  
Wide Range ◽  
Statistical Designs

Abstract High-velocity air fuel (HVAF) spraying was selected for spray trials of a Cr3C2-NiCr powder. To determine the effect of spray parameters on coating characteristics, particularly porosity and phase degradation, a statistical design of experiments was implemented. A wide range of statistical designs have been applied to the optimization of thermal spray coatings with a great deal of success. In this instance, a lack of prior knowledge and the need to assess many process-variable interactions efficiently led to the selection of a two-level full factorial design. High and low settings for each variable, including spray distance, traverse speed, and powder feedrate, were chosen based on the ranges typically used to spray similar materials. The resulting coatings were assessed for microhardness, porosity, residual stress, deposition efficiency, and phase transformation, after which several follow-up runs were conducted to explore trends brought to light by the initial factorial design.

scholarly journals Recent Advances in Glycerol Catalytic Valorization: A Review

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1279
Author(s):  
Manuel Checa ◽  
Sergio Nogales-Delgado ◽  
Vicente Montes ◽  
José María Encinar
Keyword(s):  
Activated Carbon ◽  
Carboxylic Acids ◽  
Large Scale ◽  
Biodiesel Production ◽  
Added Value ◽  
Scale Production ◽  
Recent Advances ◽  
Large Scale Production ◽  
Wide Range ◽  
Technological Limitations

Once a biorefinery is ready to operate, the main processed materials need to be completely evaluated in terms of many different factors, including disposal regulations, technological limitations of installation, the market, and other societal considerations. In biorefinery, glycerol is the main by-product, representing around 10% of biodiesel production. In the last few decades, the large-scale production of biodiesel and glycerol has promoted research on a wide range of strategies in an attempt to valorize this by-product, with its transformation into added value chemicals being the strategy that exhibits the most promising route. Among them, C3 compounds obtained from routes such as hydrogenation, oxidation, esterification, etc. represent an alternative to petroleum-based routes for chemicals such as acrolein, propanediols, or carboxylic acids of interest for the polymer industry. Another widely studied and developed strategy includes processes such as reforming or pyrolysis for energy, clean fuels, and materials such as activated carbon. This review covers recent advances in catalysts used in the most promising strategies considering both chemicals and energy or fuel obtention. Due to the large variety in biorefinery industries, several potential emergent valorization routes are briefly summarized.

scholarly journals Expansion of Human Pluripotent Stem Cell-derived Early Cardiovascular Progenitor Cells by a Cocktail of Signaling Factors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sadaf Vahdat ◽  
Sara Pahlavan ◽  
Elena Mahmoudi ◽  
Maryam Barekat ◽  
Hassan Ansari ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Large Scale ◽  
Culture Medium ◽  
Gene Expression Pattern ◽  
Extended Period ◽  
Scale Production ◽  
Chemical Screening ◽  
Wide Range ◽  
Cell Sources

Abstract Cardiovascular progenitor cells (CPCs) derived from human pluripotent stem cells (hPSCs) are proposed to be invaluable cell sources for experimental and clinical studies. This wide range of applications necessitates large-scale production of CPCs in an in vitro culture system, which enables both expansion and maintenance of these cells. In this study, we aimed to develop a defined and efficient culture medium that uses signaling factors for large-scale expansion of early CPCs, called cardiogenic mesodermal cells (CMCs), which were derived from hPSCs. Chemical screening resulted in a medium that contained a reproducible combination of three factors (A83-01, bFGF, and CHIR99021) that generated 1014 CMCs after 10 passages without the propensity for tumorigenicity. Expanded CMCs retained their gene expression pattern, chromosomal stability, and differentiation tendency through several passages and showed both the safety and possible cardio-protective potentials when transplanted into the infarcted rat myocardium. These CMCs were efficiently cryopreserved for an extended period of time. This culture medium could be used for both adherent and suspension culture conditions, for which the latter is required for large-scale CMC production. Taken together, hPSC-derived CMCs exhibited self-renewal capacity in our simple, reproducible, and defined medium. These cells might ultimately be potential, promising cell sources for cardiovascular studies.

scholarly journals Study on optimum technological conditions for producing androstenedione by microbial method

2019 ◽  
Vol 136 ◽  
pp. 06025
Author(s):  
Haishan SHI ◽  
Ying YANG ◽  
Weihua LI ◽  
Hui ZHANG ◽  
Xiaolei CHENG
Keyword(s):  
Substrate Concentration ◽  
Large Scale ◽  
Supply And Demand ◽  
Process Conditions ◽  
Phase System ◽  
Scale Production ◽  
Liquid Loading ◽  
Two Phase ◽  
Initial Ph ◽  
Promising Development

As an indispensable intermediate, androstenedione is widely used in drug manufacturing, especially steroidal drugs. However, the chemical manufacturing process of androstenedione is generally complicated and difficult, and it will cause serious environmental pollution in the production process. The biological method for the production of androstenedione has a very promising development prospect, because it is more economical and environmentally friendly than chemical methods. In order to better produce androstenedione on a large scale, the imbalance between supply and demand can be solved. In this study, the biaqueous phase system was used to increase the substrate concentration, and the method of transforming plant sterol by mycobacterium was used to produce androstenedione. The optimal conditions for the production of androstenedione by microbial assay were determined by orthogonal test: the aqueous two-phase system was water/ sunflower oil, the temperature was 30 °C, the initial pH was 6.5, the substrate concentration was 0.4 g/L, the rotation speed was 250 rpm, and the inoculation was carried out. The amount was 14.83%, the organic ratio was 20.65%, and the liquid loading was 150/500 mL. The preliminary production of androstenedione by microbial method has found suitable process conditions and provided data and theoretical support for its large-scale production.

scholarly journals Determination of the Structural Integrity and Stability of Polysialic Acid during Alkaline and Thermal Treatment

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 165
Author(s):  
Bastian Bartling ◽  
Johanna S. Rehfeld ◽  
Daniel Boßmann ◽  
Ingo de Vries ◽  
Jörg Fohrer ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Large Scale ◽  
Polysialic Acid ◽  
Alkaline Solutions ◽  
Low Molecular Weight ◽  
Outer Cell ◽  
Scale Production ◽  
Thermal Hydrolysis ◽  
E Coli ◽  
Chain Lengths

Polysialic acid (polySia) is a linear homopolymer of varying chain lengths that exists mostly on the outer cell membrane surface of certain bacteria, such as Escherichia coli (E. coli) K1. PolySia, with an average degree of polymerization of 20 (polySia avDP20), possesses material properties that can be used for therapeutic applications to treat inflammatory neurodegenerative diseases. The fermentation of E. coli K1 enables the large-scale production of endogenous long-chain polySia (DP ≈ 130) (LC polySia), from which polySia avDP20 can be manufactured using thermal hydrolysis. To ensure adequate biopharmaceutical quality of the product, the removal of byproducts and contaminants, such as endotoxins, is essential. Recent studies have revealed that the long-term incubation in alkaline sodium hydroxide (NaOH) solutions reduces the endotoxin content down to 3 EU (endotoxin units) per mg, which is in the range of pharmaceutical applications. In this study, we analyzed interferences in the intramolecular structure of polySia caused by harsh NaOH treatment or thermal hydrolysis. Nuclear magnetic resonance (NMR) spectroscopy revealed that neither the incubation in an alkaline solution nor the thermal hydrolysis induced any chemical modification. In addition, HPLC analysis with a preceding 1,2-diamino-4,5-methylenedioxybenzene (DMB) derivatization demonstrated that the alkaline treatment did not induce any hydrolytic effects to reduce the maximum polymer length and that the controlled thermal hydrolysis reduced the maximum chain length effectively, while cost-effective incubation in alkaline solutions had no adverse effects on LC polySia. Therefore, both methods guarantee the production of high-purity, low-molecular-weight polySia without alterations in the structure, which is a prerequisite for the submission of a marketing authorization application as a medicinal product. However, a specific synthesis of low-molecular-weight polySia with defined chain lengths is only possible to a limited extent.

scholarly journals Advances in the Metabolic Engineering of Escherichia coli for the Manufacture of Monoterpenes

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 433 ◽  
Author(s):  
Si-si Xie ◽  
Lingyun Zhu ◽  
Xin-yuan Qiu ◽  
Chu-shu Zhu ◽  
Lv-yun Zhu
Keyword(s):  
Large Scale ◽  
Metabolic Flux ◽  
Process Development ◽  
Pathway Engineering ◽  
Scale Production ◽  
Future Studies ◽  
E Coli ◽  
Large Scale Production ◽  
Rate Limiting ◽  
Dependent Pathway

Monoterpenes are commonly applied as pharmaceuticals and valuable chemicals in various areas. The bioproduction of valuable monoterpenes in prokaryotic microbial hosts, such as E. coli, has progressed considerably thanks to the development of different outstanding approaches. However, the large-scale production of monoterpenes still presents considerable limitations. Thus, process development warrants further investigations. This review discusses the endogenous methylerythritol-4-phosphate-dependent pathway engineering and the exogenous mevalonate-dependent isoprenoid pathway introduction, as well as the accompanied optimization of rate-limiting enzymes, metabolic flux, and product toxicity tolerance. We suggest further studies to focus on the development of systematical, integrational, and synthetic biological strategies in light of the inter disciplines at the cutting edge. Our review provides insights into the current advances of monoterpene bioengineering and serves as a reference for future studies to promote the industrial production of valuable monoterpenes.

scholarly journals Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels

2020 ◽  
Vol 10 (6) ◽  
pp. 2082 ◽  
Author(s):  
Jaber E. Abu Qudeiri ◽  
Aiman Zaiout ◽  
Abdel-Hamid I. Mourad ◽  
Mustufa Haider Abidi ◽  
Ahmed Elkaseer
Keyword(s):  
Large Scale ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Future Research ◽  
Process Conditions ◽  
Process Performance ◽  
Die Steels ◽  
Wide Range ◽  
Complex Shapes ◽  
Manufacturing Technologies

Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research community.

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