scholarly journals Efficient Production of l-Ribose with a Recombinant Escherichia coli Biocatalyst

2008 ◽  
Vol 74 (10) ◽  
pp. 2967-2975 ◽  
Author(s):  
Ryan D. Woodyer ◽  
Nathan J. Wymer ◽  
F. Michael Racine ◽  
Shama N. Khan ◽  
Badal C. Saha
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Active Form ◽  
Apium Graveolens ◽  
Efficient Production ◽  
Scale Production ◽  
Gene Encoding ◽  
Large Scale Production ◽  
One Step ◽  
Rare Sugars

ABSTRACT A new synthetic platform with potential for the production of several rare sugars, with l-ribose as the model target, is described. The gene encoding the unique NAD-dependent mannitol-1-dehydrogenase (MDH) from Apium graveolens (garden celery) was synthetically constructed for optimal expression in Escherichia coli. This MDH enzyme catalyzes the interconversion of several polyols and their l-sugar counterparts, including the conversion of ribitol to l-ribose. Expression of recombinant MDH in the active form was successfully achieved, and one-step purification was demonstrated. Using the created recombinant E. coli strain as a whole-cell catalyst, the synthetic utility was demonstrated for production of l-ribose, and the system was improved using shaken flask experiments. It was determined that addition of 50 to 500 μM ZnCl2 and addition of 5 g/liter glycerol both improved production. The final levels of conversion achieved were >70% at a concentration of 40 g/liter and >50% at a concentration of 100 g/liter. The best conditions determined were then scaled up to a 1-liter fermentation that resulted in 55% conversion of 100 g/liter ribitol in 72 h, for a volumetric productivity of 17.4 g liter−1 day−1. This system represents a significantly improved method for the large-scale production of l-ribose.

scholarly journals Tolerance engineering in Deinococcus geothermalis by heterologous efflux pumps

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erika Boulant ◽  
Emmanuelle Cambon ◽  
Julia Vergalli ◽  
Rémi Bernard ◽  
Fabienne Neulat-Ripoll ◽  
...  
Keyword(s):  
Large Scale ◽  
Efflux Pumps ◽  
Toxic Effects ◽  
Efficient Production ◽  
Scale Production ◽  
Gene Encoding ◽  
Large Scale Production ◽  
Deinococcus Geothermalis ◽  
Genes Encoding ◽  
Susceptibility Tests

AbstractProducing industrially significant compounds with more environmentally friendly represents a challenging task. The large-scale production of an exogenous molecule in a host microfactory can quickly cause toxic effects, forcing the cell to inhibit production to survive. The key point to counter these toxic effects is to promote a gain of tolerance in the host, for instance, by inducing a constant flux of the neo-synthetized compound out of the producing cells. Efflux pumps are membrane proteins that constitute the most powerful mechanism to release molecules out of cells. We propose here a new biological model, Deinococcus geothermalis, organism known for its ability to survive hostile environment; with the aim of coupling the promising industrial potential of this species with that of heterologous efflux pumps to promote engineering tolerance. In this study, clones of D. geothermalis containing various genes encoding chromosomal heterologous efflux pumps were generated. Resistant recombinants were selected using antibiotic susceptibility tests to screen promising candidates. We then developed a method to determine the efflux efficiency of the best candidate, which contains the gene encoding the MdfA of Salmonella enterica serovar Choleraesuis. We observe 1.6 times more compound in the external medium of the hit recombinant than that of the WT at early incubation time. The data presented here will contribute to better understanding of the parameters required for efficient production in D. geothermalis.

scholarly journals A Review on Additive Manufacturing Possibilities for Electrical Machines

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Three Dimensional ◽  
Electrical Machines ◽  
Electromagnetic Properties ◽  
Scale Production ◽  
Performance Parameters ◽  
Large Scale Production ◽  
One Step ◽  
Manufacturing Techniques

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.

Large-scale production of citrate synthase from a cloned gene

1982 ◽  
Vol 60 (12) ◽  
pp. 1143-1147 ◽  
Author(s):  
Harry W. Duckworth ◽  
Alexander W. Bell
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Citrate Synthase ◽  
Specific Activity ◽  
Tetracycline Resistance ◽  
Scale Production ◽  
Ampicillin Resistance ◽  
Colicin E1 ◽  
Large Scale Production ◽  
Cloned Gene

Starting with a colicin E1 resistance recombinant plasmid which contains gltA, the gene for citrate synthase in Escherichia coli, we have constructed an ampicillin-resistance plasmid containing the gltA region as a 2.9-kilobase-pair insert in the tetracycline-resistance region of pBR322. Escherichia coli HB101 harbouring this plasmid, when grown on rich medium containing ampicillin, contains citrate synthase as about 8% of its soluble protein. The enzyme has been purified from this rich source and is identical to the chromosomal enzyme prepared previously in every property tested, except for specific activity, which is 64 U∙mg−1 as compared with 45–50 U∙mg−1 previously obtained. The N-terminal sequences of both enzymes are reported, and they are identical up to residue 16 at least. The overall yield of pure enzyme, starting with the cells grown in 15 L of medium, is 600–800 mg.

A Simple and Effective Method for the Preparation of Porous Graphene Nanosheets

2015 ◽  
Vol 719-720 ◽  
pp. 123-126
Author(s):  
Jin Sun ◽  
Qing Zhong Xue ◽  
Yong Gang Du ◽  
Fu Jun Xia ◽  
Qi Kai Guo
Keyword(s):  
Large Scale ◽  
Graphene Nanosheets ◽  
Scale Production ◽  
Green Method ◽  
Porous Graphene ◽  
Large Scale Production ◽  
Potential Applications ◽  
One Step ◽  
Autogenous Pressure ◽  
The One

Porous graphene is a collection of graphene-related materials which exhibits properties distinct from those of graphene, and it has widespread potential applications in various fields. Several approaches have been developed to produce porous graphene. However, the large-scale production of porous graphene nanosheets still remains a great challenge. Moreover, the costs of some methods are prohibitive for its commercial production and the processes are too complicated and time-consuming. In this work, we propose a simple and green method by which graphene nanosheets can be etched by sodium hydroxide under autogenous pressure at 180 °C. The morphologies and surface elements of the porous graphene nanosheets and sizes of pores were characterized. It is demonstrated that the one-step etching of graphene nanosheets is an effective method to obtain large-scale porous graphene nanosheets with high and uniform porosity. The pores in the porous graphene nanosheets were 6 nm depth (the same as the thickness of the graphene nanosheets) and 30-50 nm width.

scholarly journals Biosynthesis And Structural Characterization of Levan By A Recombinant Levansucrase From Bacillus Subtilis ZW019

2021 ◽  
Author(s):  
Jingyue Wang ◽  
Xinan Xu ◽  
Fangkun Zhao ◽  
Nan Yin ◽  
Zhijiang Zhou ◽  
...  
Keyword(s):  
Large Scale ◽  
Fermentation Broth ◽  
Monosaccharide Composition ◽  
Enzymatic Reactions ◽  
Scale Production ◽  
Large Scale Production ◽  
Nmr Techniques ◽  
One Step ◽  
Activity Of Enzymes

Abstract Purpose: The yield of levan extracted from microbial fermentation broth is low, so in vitro catalytic synthesis of levan by levansucrase is expected to be one of the industrial production approaches of levan. Methods: A recombinant plasmid pET-28a-AcmA-Z constructed in the previous study was used to produce levansucrase. The effects of temperature, pH, and metal ions on the levan formation activity of the levansucrase were investigated. The polymer was analyzed by means of HPIC, FTIR, NMR techniques.Results: The recombinant levansucrase could be easily purified in one step and the purified enzyme had a single band clearly visible in SDS-PAGE. The conditions for enzymatic reactions was optimal at pH 5.2 and 40 ℃, and the activity of enzymes was stimulated by K+ and Ca2+. The yield of levan biosynthesis from 10% (w/v) sucrose with 6.45 U/g sucrose of levansucrase was 30.6 g/L. The molecular weight of the levan was about 1.56×106 Da, as measured by GPC. HPIC analysis showed that the monosaccharide composition of the levan was fructose and glucose. The results of FTIR and NMR analysis indicated that the polymer produced by the recombinant levansucrase was β-(2, 6) levan.Conclusions: The results of this study provide a basis for large-scale production of levan by enzymatic method.

One-step synthesis and assembly of spindle-shaped akaganéite nanoparticles via sonochemistry

CrystEngComm ◽  
2018 ◽  
Vol 20 (21) ◽  
pp. 2989-2995 ◽  
Author(s):  
Weikun Chen ◽  
Pinqiang Dai ◽  
Chunfu Hong ◽  
Chan Zheng ◽  
Weiguo Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Scale Production ◽  
Green Method ◽  
Large Scale Production ◽  
One Step

We demonstrate a green method based on sonochemistry for large-scale production of akaganéite nanoparticles and assemblies in low cost.

Scalable one-step production of electrochemically exfoliated graphene decorated with transition metal oxides for high-performance supercapacitors

Nanoscale ◽  
2021 ◽  
Author(s):  
Adrián Romaní Vázquez ◽  
Christof Neumann ◽  
Mino Borrelli ◽  
Huanhuan Shi ◽  
Matthias Kluge ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Transition Metal Oxides ◽  
High Performance ◽  
Large Scale ◽  
Wide Field ◽  
Scale Production ◽  
Exfoliated Graphene ◽  
Large Scale Production ◽  
One Step ◽  
Critical Challenge

Graphene and related materials have been widely studied for their superior properties in a wide field of applications. However, large-scale production remains a critical challenge to enable commercial acceptance. Here,...

scholarly journals Replacement of a Metabolic Pathway for Large-Scale Production of Lactic Acid from Engineered Yeasts

1999 ◽  
Vol 65 (9) ◽  
pp. 4211-4215 ◽  
Author(s):  
Danilo Porro ◽  
Michele M. Bianchi ◽  
Luca Brambilla ◽  
Rossella Menghini ◽  
Davide Bolzani ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Large Scale ◽  
Kluyveromyces Lactis ◽  
Lactic Acid Production ◽  
Pyruvate Decarboxylase ◽  
Polymer Materials ◽  
Efficient Production ◽  
Scale Production ◽  
High Productivity ◽  
Large Scale Production

ABSTRACT Interest in the production of l-(+)-lactic acid is presently growing in relation to its applications in the synthesis of biodegradable polymer materials. With the aim of obtaining efficient production and high productivity, we introduced the bovinel-lactate dehydrogenase gene (LDH) into a wild-type Kluyveromyces lactis yeast strain. The observed lactic acid production was not satisfactory due to the continued coproduction of ethanol. A further restructuring of the cellular metabolism was obtained by introducing the LDH gene into aK. lactis strain in which the unique pyruvate decarboxylase gene had been deleted. With this modified strain, in which lactic fermentation substituted completely for the pathway leading to the production of ethanol, we obtained concentrations, productivities, and yields of lactic acid as high as 109 g liter−1, 0.91 g liter−1 h−1, and 1.19 mol per mole of glucose consumed, respectively. The organic acid was also produced at pH levels lower than those usual for bacterial processes.

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