scholarly journals Reductive enzymatic dynamic kinetic resolution affording 115 g/L (S)-2-phenylpropanol

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Christian Rapp ◽  
Simone Pival-Marko ◽  
Erika Tassano ◽  
Bernd Nidetzky ◽  
Regina Kratzer
Keyword(s):  
Kinetic Resolution ◽  
Single Point ◽  
Xylose Reductase ◽  
Catalytic Efficiency ◽  
Dry Weight ◽  
Catalyst Loading ◽  
Amino Acid Residues ◽  
A Value ◽  
Very High

Abstract Background Published biocatalytic routes for accessing enantiopure 2-phenylpropanol using oxidoreductases afforded maximal product titers of only 80 mM. Enzyme deactivation was identified as the major limitation and was attributed to adduct formation of the aldehyde substrate with amino acid residues of the reductase. Results A single point mutant of Candida tenuis xylose reductase (CtXR D51A) with very high catalytic efficiency (43·103 s−1 M−1) for (S)-2-phenylpropanal was found. The enzyme showed high enantioselectivity for the (S)-enantiomer but was deactivated by 0.5 mM substrate within 2 h. A whole-cell biocatalyst expressing the engineered reductase and a yeast formate dehydrogenase for NADH-recycling provided substantial stabilization of the reductase. The relatively slow in situ racemization of 2-phenylpropanal and the still limited biocatalyst stability required a subtle adjustment of the substrate-to-catalyst ratio. A value of 3.4 gsubstrate/gcell-dry-weight was selected as a suitable compromise between product ee and the conversion ratio. A catalyst loading of 40 gcell-dry-weight was used to convert 1 M racemic 2-phenylpropanal into 843 mM (115 g/L) (S)-phenylpropanol with 93.1% ee. Conclusion The current industrial production of profenols mainly relies on hydrolases. The bioreduction route established here represents an alternative method for the production of profenols that is competitive with hydrolase-catalyzed kinetic resolutions.

scholarly journals Enzymatic Dynamic Reductive Kinetic Resolution Towards 115 g/L (S)-2-Phenylpropanol

2021 ◽  
Author(s):  
Christian Rapp ◽  
Simone Pival-Marko ◽  
Erika Tassano ◽  
Bernd Nidetzky ◽  
Regina Kratzer
Keyword(s):  
Kinetic Resolution ◽  
Single Point ◽  
Xylose Reductase ◽  
Catalytic Efficiency ◽  
Dry Weight ◽  
Catalyst Loading ◽  
A Value ◽  
Whole Cell Biocatalyst ◽  
Very High

Abstract BackgroundPublished biocatalytic routes towards chiral 2-phenylpropanol by oxidoreductases showed product concentrations of maximally 80 mM. Enzyme deactivation turned out as one major limitation and was attributed to adduct formation of the aldehyde substrate with the catalytic reductase.ResultsA Candida tenuis xylose reductase single-point mutant (CtXR D51A) with very high catalytic efficiency (43·103 s-1M-1) for (S)-2-phenylpropanal was identified. The enzyme showed high enantioselectivity for the (S)-enantiomer but was deactivated by 0.5 mM substrate within 2 h. A whole-cell biocatalyst based on the engineered reductase and a yeast formate dehydrogenase for NADH-recycling provided substantial stabilization of the reductase. The relatively slow in situ racemization of 2-phenylpropanal and the still limited biocatalyst stability required a subtle adjustment of the substrate-to-catalyst ratio. A value of 3.4 gsubstrate/gcell-dry-weight turned out as compromise between product enantiopurity and conversion. A catalyst loading of 40 gcell-dry-weight was used to convert 1 M racemic 2-phenylpropanal to (S)-phenylpropanol in 93.1 % e.e. ConclusionMainly hydrolases have been exploited for the production of profenols at industrial scale so far. The herein established bioreduction presents an alternative route towards profenols that is competitive to hydrolase-catalyzed kinetic resolutions.

Organic Farming System for Producing Healthy Rice Oleh

2018 ◽  
Vol 9 (04) ◽  
pp. 20213-20217
Author(s):  
Dr. Ir. Ni.Gst.Ag.Gde Eka Martiningsih ◽  
Dr.Ir. I Putu Sujana, MS
Keyword(s):  
Elementary Education ◽  
Dry Weight ◽  
Farming System ◽  
Rice Cultivation ◽  
Cultivation System ◽  
Organic Rice ◽  
Organic Cultivation ◽  
A Value ◽  
Cultivation Technology ◽  
Organic Farming System

Introduction of organic rice-based rice cultivation technology package through demplot is done in Subak Sungi 1 using ciherang variety. The number of farmers participating in demonstration plots in organic cultivation of paddy-based rice cultivation were 5 people, with age of farmers aged greater than 55 years occupying the highest percentage (45.45%), with elementary education level (72.75%), followed by high school education (18.25%), and junior high (9%). The average farmland area is 34.63 acres, with self-owned status (55,94%), status as penyakap 41,18% and rent status 2,88%. The farmers' response to the organic rice-based rice planting assessment is quite high, as evidenced by the evaluation that 100% of farmers participating in demonstration plots know and understand about organic rice system cultivation, and they agree to develop this cultivation system in the future. Demplot research results can increase the yield components and weight of dry grain harvest per hectare. Organic rice-based rice cultivation technology EVAGRO able to increase production of dry grain harvest significantly with a value of 6.8 tons / ha. There is a tendency of dry weight value of ciherang varieties of 6.8 tons / ha giving highest but not significantly different with PGPR organic based technology.

scholarly journals Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2554
Author(s):  
Oleg Naimark ◽  
Vladimir Oborin ◽  
Mikhail Bannikov ◽  
Dmitry Ledon
Keyword(s):  
Fatigue Damage ◽  
Kinetic Equations ◽  
Experimental Methodology ◽  
Preliminary Deformation ◽  
Scaling Properties ◽  
In Situ Data ◽  
Number Of Cycles ◽  
Fish Eye ◽  
Very High

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to “in situ” data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, “fish-eye” nucleation, and transition to the Paris crack kinetics. These equations, based on empirical parameters related to the structure of the material, allows us to estimate the number of cycles for the nucleation and advance of fatigue crack.

scholarly journals A Pixel Design of a Branching Ultra-Highspeed Image Sensor

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2506
Author(s):  
Nguyen Hoai Ngo ◽  
Kazuhiro Shimonomura ◽  
Taeko Ando ◽  
Takayoshi Shimura ◽  
Heiji Watanabe ◽  
...  
Keyword(s):  
Image Sensor ◽  
Frame Rate ◽  
Front Side ◽  
Digital Signals ◽  
Memory Element ◽  
Image Capture ◽  
Readout Circuits ◽  
Pros And Cons ◽  
Very High

A burst image sensor named Hanabi, meaning fireworks in Japanese, includes a branching CCD and multiple CMOS readout circuits. The sensor is backside-illuminated with a light/charge guide pipe to minimize the temporal resolution by suppressing the horizontal motion of signal carriers. On the front side, the pixel has a guide gate at the center, branching to six first-branching gates, each bifurcating to second-branching gates, and finally connected to 12 (=6×2) floating diffusions. The signals are either read out after an image capture operation to replay 12 to 48 consecutive images, or continuously transferred to a memory chip stacked on the front side of the sensor chip and converted to digital signals. A CCD burst image sensor enables a noiseless signal transfer from a photodiode to the in-situ storage even at very high frame rates. However, the pixel count conflicts with the frame count due to the large pixel size for the relatively large in-pixel CCD memory elements. A CMOS burst image sensor can use small trench-type capacitors for memory elements, instead of CCD channels. However, the transfer noise from a floating diffusion to the memory element increases in proportion to the square root of the frame rate. The Hanabi chip overcomes the compromise between these pros and cons.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

scholarly journals THE MOLECULAR WEIGHT OF RHODOPSIN AND THE NATURE OF THE RHODOPSIN-DIGITONIN COMPLEX

1954 ◽  
Vol 37 (3) ◽  
pp. 381-399 ◽  
Author(s):  
Ruth Hubbard
Keyword(s):  
Molecular Weight ◽  
Single Molecule ◽  
Extinction Coefficient ◽  
Dry Weight ◽  
Weight Basis ◽  
Sedimentation Behavior ◽  
A Value ◽  
Wet Weight ◽  
Single Boundary ◽  
Stoichiometric Complex

The sedimentation behavior of aqueous solutions of digitonin and of cattle rhodopsin in digitonin has been examined in the ultracentrifuge. In confirmation of earlier work, digitonin was found to sediment as a micelle (D-1) with an s20 of about 6.35 Svedberg units, and containing at least 60 molecules. The rhodopsin solutions sediment as a stoichiometric complex of rhodopsin with digitonin (RD-1) with an s20 of about 9.77 Svedberg units. The s20 of the RD-1 micelle is constant between pH 6.3 and 9.6, and in the presence of excess digitonin. RD-1 travels as a single boundary also in the electrophoresis apparatus at pH 8.5, and on filter paper at pH 8.0. The molecular weight of the RD-1 micelle lies between 260,000 and 290,000. Of this, only about 40,000 gm. are due to rhodopsin; the rest is digitonin (180 to 200 moles). Comparison of the relative concentrations of RD-1 and retinene in solutions of rhodopsin-digitonin shows that RD-1 contains only one retinene equivalent. It can therefore contain only one molecule of rhodopsin with a molecular weight of about 40,000. Cattle rhodopsin therefore contains only one chromophore consisting of a single molecule of retinene. It is likely that frog rhodopsin has a similar molecular weight and also contains only one chromophore per molecule. The molar extinction coefficient of rhodopsin is therefore identical with the extinction coefficient per mole of retinene (40,600 cm.2 per mole) and the E(1 per cent, 1 cm., 500 mµ) has a value of about 10. Rhodopsin constitutes about 14 per cent of the dry weight, and 3.7 per cent of the wet weight of cattle outer limbs. This corresponds to about 4.2 x 106 molecules of rhodopsin per outer limb. The rhodopsin content of frog outer limbs is considerably higher: about 35 per cent of the dry weight, and 10 per cent of the wet weight, corresponding to about 2.1 x 109 molecules per outer limb. Thus the frog outer limb contains about five hundred times as much rhodopsin as the cattle outer limb. But the relative volumes of these structures are such that the ratio of concentrations is only about 2.5 to 1 on a weight basis. Rhodopsin accounts for at least one-fifth of the total protein of the cattle outer limb; for the frog, this value must be higher. The extinction (K500) along its axis is about 0.037 cm.2 for the cattle outer limb, and about 0.50 cm.2 for the frog outer limb.

In-situ variable-temperature single-point NMR imaging study of coals

Fuel ◽  
2000 ◽  
Vol 79 (3-4) ◽  
pp. 405-416 ◽  
Author(s):  
K Saito ◽  
I Komaki ◽  
K.-I Hasegawa ◽  
H Tsuno
Keyword(s):  
Variable Temperature ◽  
Single Point ◽  
Imaging Study ◽  
Nmr Imaging

Investigation of Emulsion Flow in Steam-Assisted Gravity Drainage

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 440-447 ◽  
Author(s):  
C.C.. C. Ezeuko ◽  
J.. Wang ◽  
I.D.. D. Gates
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Oil Recovery ◽  
Vital Role ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Emulsion Flow ◽  
Very High ◽  
Effective Representation

Summary We present a numerical simulation approach that allows incorporation of emulsion modeling into steam-assisted gravity-drainage (SAGD) simulations with commercial reservoir simulators by means of a two-stage pseudochemical reaction. Numerical simulation results show excellent agreement with experimental data for low-pressure SAGD, accounting for approximately 24% deficiency in simulated oil recovery, compared with experimental data. Incorporating viscosity alteration, multiphase effect, and enthalpy of emulsification appears sufficient for effective representation of in-situ emulsion physics during SAGD in very-high-permeability systems. We observed that multiphase effects appear to dominate the viscosity effect of emulsion flow under SAGD conditions of heavy-oil (bitumen) recovery. Results also show that in-situ emulsification may play a vital role within the reservoir during SAGD, increasing bitumen mobility and thereby decreasing cumulative steam/oil ratio (cSOR). Results from this work extend understanding of SAGD by examining its performance in the presence of in-situ emulsification and associated flow of emulsion with bitumen in porous media.

scholarly journals Asymmetric Pd-NHC*-catalyzed coupling reactions

2012 ◽  
Vol 84 (8) ◽  
pp. 1741-1748 ◽  
Author(s):  
E. Peter Kündig ◽  
Yixia Jia ◽  
Dmitry Katayev ◽  
Masafumi Nakanishi
Keyword(s):  
High Temperature ◽  
Coupling Reactions ◽  
Structural Studies ◽  
Methylene Unit ◽  
Asymmetric Coupling ◽  
New Applications ◽  
Very High

Very high asymmetric inductions result in the Pd-catalyzed intramolecular arylation of amides to give 3,3-disubstituted oxindoles when new in situ-generated chiral N-heterocyclic carbene (NHC*) ligands are employed. Structural studies show that conformational locking to minimize allylic strain is the key to understanding the function of these ligands. New applications of these ligands in the frontier area of asymmetric coupling reactions involving C(sp3)–H bonds are detailed. Highly enantioenriched fused indolines are accessible using either preformed- or in situ-generated Pd-NHC* catalysts. Remarkably, this occurs at high temperature (140–160 °C) via excellent asymmetric recognition of an enantiotopic C–H bond in an unactivated methylene unit.

Assessing Soil and Plant Pollution by Abandoned Rural Waste Dumping Sites in Ningbo, China

2011 ◽  
Vol 138-139 ◽  
pp. 1149-1155 ◽  
Author(s):  
Yi Dong Guan ◽  
Ye Hong Du ◽  
Zhen Dong Li ◽  
An Cheng Luo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reference Value ◽  
Dry Weight ◽  
Rice Grain ◽  
Contamination Assessment ◽  
Plant Parts ◽  
Metal Contents ◽  
Plant Pollution

This paper reports the concentration of heavy metals (Cr, Cu, Zn, Cd and Pb) in the soils and rices surrounding the abandoned rural waste dumping sites in Ningbo. Igeo (geoaccumulation index) was calculated to assess the contamination degree of heavy metals in soils. The mean contents of Cr, Cu, Cd, Zn and Pb of soils were 33.3, 24.1, 1.5, 118.9 and 45.6 mg/(kg DW) (dry weight), respectively. All of them were much higher than that of the reference value (i.e. CK), but there were no coherent trend of the metal contents within 1-120m distance from the dumping site. Igeo of heavy metals reveals the order of Cd>Cu>Cr>Pb>Zn, and the contamination assessment of soils using Igeo indicate the moderate Cd pollution, while the soils were unpolluted-moderately overall by Cr, Cu, Zn as well as Pb. The heavy metal contents in root, stem & leaf and rice grains were all remarkable higher than that of the CK at 20-120 m distances, and the heavy metal contents in root were evidently much higher than other plant parts, while those in rice grain were lowest, indicating the great bioaccumulation trend of heavy metals. Although the metal contents in the rice grain were within the legislation limit, its bioaccumulation trend of heavy metals was remarkable, whose contents were 4.38-fold for Cr, 1.76-fold for Cu, 1.28-fold for Zn, 2.67-fold for Cd and 3.03-fold for Pb higher than that of reference value, respectively. Finally, we proposed a decentralized in-situ restoration approach for the dumping sites.

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