scholarly journals Formate Dehydrogenase from Rhodococcus jostii (RjFDH) – A High‐Performance Tool for NADH Regeneration

2020 ◽  
Vol 362 (19) ◽  
pp. 4109-4118
Author(s):  
Alexander Boldt ◽  
Marion B. Ansorge‐Schumacher
Keyword(s):  
High Performance ◽  
Formate Dehydrogenase ◽  
Nadh Regeneration ◽  
Rhodococcus Jostii

scholarly journals Facile synthesis of bioactive Allitol from D-psicose by coexpression of ribitol dehydrogenase and formate dehydrogenase in Escherichia Coli

2018 ◽  
Vol 4 ◽  
Author(s):  
Hinawi A.M. Hassanin ◽  
Mohammed A.A. Eassa ◽  
Bo Jiang
Keyword(s):  
Escherichia Coli ◽  
Substrate Concentration ◽  
Formate Dehydrogenase ◽  
Maximum Yield ◽  
Optimum Conditions ◽  
Facile Synthesis ◽  
Nadh Regeneration ◽  
E Coli ◽  
Ribitol Dehydrogenase

Coexpression of formate dehydrogenase (FDH) and ribitol dehydrogenase (RDH) in Escherichia coli was used for the synthesis of Allitol from D-psicose. FDH was coexpressed with RDH for continuous NADH regeneration. The results revealed that the optimum conditions for allitol production occurred at pH 7.0 and 30 °C. Allitol reached the maximum yield of 19.2 mg at 2.0% substrate concentration after 48 hours. Using D-psicose as a substrate, allitol was successfully produced using an engineered E. coli coexpressed with RDH and FDH.

scholarly journals Efficient 2,3-Butanediol/Acetoin Production Using Whole-Cell Biocatalyst with a New Nadh/Nad(+) Regeneration System

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1422
Author(s):  
Yaping Wang ◽  
Yanhong Peng ◽  
Xiaoyan Liu ◽  
Ronghua Zhou ◽  
Xianqing Liao ◽  
...  
Keyword(s):  
Formate Dehydrogenase ◽  
Target Genes ◽  
Nadh Oxidase ◽  
Expression System ◽  
Regeneration System ◽  
Nadh Regeneration ◽  
Whole Cell ◽  
Whole Cell Biocatalyst ◽  
Acetoin Production ◽  
Butanediol Dehydrogenase

An auto-inducing expression system was developed that could express target genes in S. marcescens MG1. Using this system, MG1 was constructed as a whole-cell biocatalyst to produce 2,3-butanediol/acetoin. Formate dehydrogenase (FDH) and 2,3-butanediol dehydrogenase were expressed together to build an NADH regeneration system to transform diacetyl to 2,3-butanediol. After fermentation, the extract of recombinant S. marcescens MG1ABC (pETDuet-bdhA-fdh) showed 2,3-BDH activity of 57.8 U/mg and FDH activity of 0.5 U/mg. And 27.95 g/L of 2,3-BD was achieved with a productivity of 4.66 g/Lh using engineered S. marcescens MG1(Pswnb+pETDuet-bdhA-fdh) after 6 h incubation. Next, to produce 2,3-butanediol from acetoin, NADH oxidase and 2,3-butanediol dehydrogenase from Bacillus subtilis were co-expressed to obtain a NAD+ regeneration system. After fermentation, the recombinant strain S. marcescens MG1ABC (pSWNB+pETDuet-bdhA-yodC) showed AR activity of 212.4 U/mg and NOX activity of 150.1 U/mg. We obtained 44.9 g/L of acetoin with a productivity of 3.74 g/Lh using S. marcescens MG1ABC (pSWNB+pETDuet-bdhA-yodC). This work confirmed that S. marcescens could be designed as a whole-cell biocatalyst for 2,3-butanediol and acetoin production.

scholarly journals A Novel 3-Phytosterone-9α-Hydroxylase Oxygenation Component and Its Application in Bioconversion of 4-Androstene-3,17-Dione to 9α-Hydroxy-4-Androstene-3,17-Dione Coupling with A NADH Regeneration Formate Dehydrogenase

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2534 ◽  
Author(s):  
Xian Zhang ◽  
Manchi Zhu ◽  
Rumeng Han ◽  
Youxi Zhao ◽  
Kewei Chen ◽  
...  
Keyword(s):  
Formate Dehydrogenase ◽  
Batch Process ◽  
Regeneration System ◽  
Optimum Ratio ◽  
Fed Batch ◽  
Nadh Regeneration ◽  
Key Enzyme ◽  
Biological Transformation ◽  
Economical Process

9α-Hydroxy-4-androstene-3,17-dione (9-OH-AD) is one of the significant intermediates for the preparation of β-methasone, dexamethasone, and other steroids. In general, the key enzyme that enables the biotransformation of 4-androstene-3,17-dione (AD) to 9-OH-AD is 3-phytosterone-9α-hydroxylase (KSH), which consists of two components: a terminal oxygenase (KshA) and ferredoxin reductase (KshB). The reaction is carried out with the concomitant oxidation of NADH to NAD+. In this study, the more efficient 3-phytosterone-9α-hydroxylase oxygenase (KshC) from the Mycobacterium sp. strain VKM Ac-1817D was confirmed and compared with reported KshA. To evaluate the function of KshC on the bioconversion of AD to 9-OH-AD, the characterization of KshC and the compounded system of KshB, KshC, and NADH was constructed. The optimum ratio of KSH oxygenase to reductase content was 1.5:1. An NADH regeneration system was designed by introducing a formate dehydrogenase, further confirming that a more economical process for biological transformation from AD to 9-OH-AD was established. A total of 7.78 g of 9-OH-AD per liter was achieved through a fed-batch process with a 92.11% conversion rate (mol/mol). This enzyme-mediated hydroxylation method provides an environmentally friendly and economical strategy for the production of 9-OH-AD.

A High Performance Energy Analyzer for Use in Electron Scanning Microscopy

1969 ◽  
Vol 27 ◽  
pp. 14-15
Author(s):  
A. V. Crewe ◽  
M. Isaacson ◽  
D. Johnson
Keyword(s):  
High Performance ◽  
Vertical Plane ◽  
Median Plane ◽  
Electron Gun ◽  
Uniform Field ◽  
Loss Mechanism ◽  
Electron Scanning Microscopy ◽  
Sector Type ◽  
Double Focusing ◽  
Electron Energy Loss

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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