scholarly journals Efficient Production of 2-Oxobutyrate from 2-Hydroxybutyrate by Using Whole Cells of Pseudomonas stutzeri Strain SDM

2010 ◽  
Vol 76 (5) ◽  
pp. 1679-1682 ◽  
Author(s):  
Chao Gao ◽  
Wen Zhang ◽  
Chuanjuan Lv ◽  
Lixiang Li ◽  
Cuiqing Ma ◽  
...  
Keyword(s):  
Pseudomonas Stutzeri ◽  
High Yield ◽  
Efficient Production ◽  
Optimal Conditions ◽  
High Concentration ◽  
Whole Cells ◽  
Food Industries ◽  
Important Intermediate ◽  
Lactate Dehydrogenases ◽  
Biocatalytic Process

ABSTRACT 2-Oxobutyrate is an important intermediate in the chemical, drug, and food industries. Whole cells of Pseudomonas stutzeri SDM, containing NAD-independent lactate dehydrogenases, effectively converted 2-hydroxybutyrate into 2-oxobutyrate. Under optimal conditions, the biocatalytic process produced 2-oxobutyrate at a high concentration (44.4 g liter−1) and a high yield (91.5%).

scholarly journals Production ofN-Acetyl-d-Neuraminic Acid by Use of an Efficient Spore Surface Display System

2011 ◽  
Vol 77 (10) ◽  
pp. 3197-3201 ◽  
Author(s):  
Xiaoman Xu ◽  
Chao Gao ◽  
Xifeng Zhang ◽  
Bin Che ◽  
Cuiqing Ma ◽  
...  
Keyword(s):  
Surface Display ◽  
Value Added ◽  
Neuraminic Acid ◽  
High Yield ◽  
Permeability Barrier ◽  
Chemical Production ◽  
High Concentration ◽  
Suitable Alternative ◽  
Content Type ◽  
Whole Cells

ABSTRACTProduction ofN-acetyl-d-neuraminic acid (Neu5Ac) via biocatalysis is traditionally conducted using isolated enzymes or whole cells. The use of isolated enzymes is restricted by the time-consuming purification process, whereas the application of whole cells is limited by the permeability barrier presented by the microbial cell membrane. In this study, a novel type of biocatalyst, Neu5Ac aldolase presented on the surface ofBacillus subtilisspores, was used for the production of Neu5Ac. Under optimal conditions, Neu5Ac at a high concentration (54.7 g liter−1) and a high yield (90.2%) was obtained under a 5-fold excess of pyruvate overN-acetyl-d-mannosamine. The novel biocatalyst system, which is able to express and immobilize the target enzyme simultaneously on the surface ofB. subtilisspores, represents a suitable alternative for value-added chemical production.

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

scholarly journals Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 601
Author(s):  
Dinh-Tuan Nguyen ◽  
Hsiang-An Ting ◽  
Yen-Hsun Su ◽  
Mario Hofmann ◽  
Ya-Ping Hsieh
Keyword(s):  
Large Scale ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Spectroscopic Characterization ◽  
High Yield ◽  
Nanometer Scale ◽  
Efficient Production ◽  
Device Performance ◽  
Metal Dichalcogenides ◽  
Scale Deposition

The success of van-der-Waals electronics, which combine large-scale-deposition capabilities with high device performance, relies on the efficient production of suitable 2D materials. Shear exfoliation of 2D materials’ flakes from bulk sources can generate 2D materials with low amounts of defects, but the production yield has been limited below industry requirements. Here, we introduce additive-assisted exfoliation (AAE) as an approach to significantly increase the efficiency of shear exfoliation and produce an exfoliation yield of 30%. By introducing micrometer-sized particles that do not exfoliate, the gap between rotor and stator was dynamically reduced to increase the achievable shear rate. This enhancement was applied to WS2 and MoS2 production, which represent two of the most promising 2D transition-metal dichalcogenides. Spectroscopic characterization and cascade centrifugation reveal a consistent and significant increase in 2D material concentrations across all thickness ranges. Thus, the produced WS2 films exhibit high thickness uniformity in the nanometer-scale and can open up new routes for 2D materials production towards future applications.

scholarly journals Pigment Production under Cold Stress in the Green Microalga Chlamydomonas reinhardtii

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 564
Author(s):  
Supakorn Potijun ◽  
Chonlada Yaisamlee ◽  
Anchalee Sirikhachornkit
Keyword(s):  
Cold Stress ◽  
Chlamydomonas Reinhardtii ◽  
Production Efficiency ◽  
Cell Physiology ◽  
Efficient Production ◽  
Increase Production Efficiency ◽  
Whole Cells ◽  
Stress Acclimation ◽  
Chlorophyll Accumulation ◽  
In The Wild

Microalgae have long been used for the commercial production of natural colorants such as carotenoids and chlorophyll. Due to the rising demand for carotenoids and other natural products from microalgae, strategies to increase production efficiency are urgently needed. The production of microalgal biorefineries has been limited to countries with moderate climates. For countries with cooler climates and less daylight, methodologies for the efficient production of microalgal biorefineries need to be investigated. Algal strains that can be safely consumed as whole cells are also attractive alternatives for developing as carotenoid supplements, which can also contain other compounds with health benefits. Using such strains helps to eliminate the need for hazardous solvents for extraction and several other complicated steps. In this study, the mesophilic green alga Chlamydomonas reinhardtii was employed to study the effects of cold stress on cell physiology and the production of pigments and storage compounds. The results showed that temperatures between 10 and 20 °C induced carotenoid and chlorophyll accumulation in the wild-type strain of C. reinhardtii. Interestingly, the increased level of carotenoids suggested that they might play a crucial role in cold stress acclimation. A temperature of 15 °C resulted in the highest carotenoid and chlorophyll productivity. At this temperature, carotenoid and chlorophyll productivity was 2 times and 1.3 times higher than at 25 °C, respectively. Subjecting a mutant defective in lutein and zeaxanthin accumulation to cold stress revealed that these two carotenoids are not essential for cold stress survival. Therefore, cold temperature could be used as a strategy to induce and increase the productivity of pigments in C. reinhardtii.

scholarly journals A method for the generation of pseudotyped virus particles bearing SARS coronavirus spike protein in high yields

2021 ◽  
Author(s):  
Yoichiro Fujioka ◽  
Sayaka Kashiwagi ◽  
Aiko Yoshida ◽  
Aya O. Satoh ◽  
Mari Fujioka ◽  
...  
Keyword(s):  
Global Economy ◽  
Expression System ◽  
Antiviral Agents ◽  
Production Method ◽  
Spike Protein ◽  
High Yield ◽  
Pseudotyped Virus ◽  
Efficient Production ◽  
Live Virus ◽  
High Yields

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has threatened human health and the global economy. Development of additional vaccines and therapeutics is urgently required, but such development with live virus must be conducted with biosafety level 3 confinement. Pseudotyped viruses have been widely adopted for studies of virus entry and pharmaceutical development to overcome this restriction. Here we describe a modified protocol to generate vesicular stomatitis virus (VSV) pseudotyped with SARS-CoV or SARS-CoV-2 Spike protein in high yield. We found that pseudovirions produced with the conventional transient expression system lacked coronavirus Spike protein at their surface as a result of inhibition of parental VSV infection by overexpression of this protein. Establishment of stable cell lines with an optimal expression level of coronavirus Spike protein allowed the efficient production of progeny pseudoviruses decorated with Spike protein. This improved VSV pseudovirus production method should facilitate studies of coronavirus entry and development of antiviral agents.

scholarly journals Efficient production of vindoline from tabersonine by metabolically engineered Saccharomyces cerevisiae

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tengfei Liu ◽  
Ying Huang ◽  
Lihong Jiang ◽  
Chang Dong ◽  
Yuanwei Gou ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
De Novo ◽  
Indole Alkaloid ◽  
Functional Expression ◽  
High Yield ◽  
Efficient Production ◽  
Cytochrome P450 Enzymes ◽  
Copy Numbers ◽  
Yield Production ◽  
Engineered Saccharomyces Cerevisiae

AbstractVindoline is a plant derived monoterpene indole alkaloid (MIA) with potential therapeutic applications and more importantly serves as the precursor to vinblastine and vincristine. To obtain a yeast strain for high yield production of vindoline from tabersonine, multiple metabolic engineering strategies were employed via the CRISPR/Cas9 mediated multiplex genome integration technology in the present study. Through increasing and tuning the copy numbers of the pathway genes, pairing cytochrome P450 enzymes (CYPs) with appropriate cytochrome P450 reductases (CPRs), engineering the microenvironment for functional expression of CYPs, enhancing cofactor supply, and optimizing fermentation conditions, the production of vindoline was increased to a final titer as high as ∼16.5 mg/L, which is more than 3,800,000-fold higher than the parent strain and the highest tabersonine to vindoline conversion yield ever reported. This work represents a key step of the engineering efforts to establish de novo biosynthetic pathways for vindoline, vinblastine, and vincristine.

scholarly journals Simultaneous and Efficient Production of Furfural and Subsequent Glucose in MTHF/H2O Biphasic System via Parameter Regulation

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 557
Author(s):  
Shaolong Sun ◽  
Xuefei Cao ◽  
Huiling Li ◽  
Yingbo Zhu ◽  
Yijing Li ◽  
...  
Keyword(s):  
Glucose Production ◽  
Biphasic System ◽  
Efficient Production ◽  
Obvious Effect ◽  
Environment Friendly ◽  
H2so4 Concentration ◽  
Food Industries ◽  
The Difference ◽  
Temperature Time ◽  
Furfural Production

Efficient production of furfural from cornstalk in 2-Methyltetrahydrofuran/aqueous (MTHF/H2O) biphasic system via parameter regulation (e.g., VMTHF/VH2O, temperature, time, and H2SO4 concentration) was proposed. The resulting solid residues achieved from the different MTHF/H2O system conditions for furfural production were also to prepare glucose by adding cellulases to increase the high-value applications of cornstalk. A maximum furfural yield (68.1%) was obtained based on reaction condition (VMTHF:VH2O = 1:1, 170 °C, 60 min, 0.05 M H2SO4). Among these parameters, the concentration of H2SO4 had the most obvious effect on the furfural production. The glucose yields of the residues acquired from different MTHF/H2O processes were enhanced and then a maximum value of 78.9% based on the maximum furfural production conditions was observed. Single factor may not be sufficient to detail the difference in glucose production, and several factors affected the hydrolysis efficiency of the residues. Overall, the MTHF/H2O system effectively converted cornstalk into furfural and glucose via a simple and environment-friendly process, thus was an ideal manner for the food industries.

scholarly journals High-yield Production of Amyloid-β Peptide Enabled by a Customized Spider Silk Domain

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Axel Abelein ◽  
Gefei Chen ◽  
Kristīne Kitoka ◽  
Rihards Aleksis ◽  
Filips Oleskovs ◽  
...  
Keyword(s):  
Spider Silk ◽  
Amyloid Β ◽  
Silk Gland ◽  
High Yield ◽  
Efficient Production ◽  
Amyloid Β Peptide ◽  
Nephila Clavipes ◽  
Recombinant Production ◽  
Yield Production ◽  
High Yields

AbstractDuring storage in the silk gland, the N-terminal domain (NT) of spider silk proteins (spidroins) keeps the aggregation-prone repetitive region in solution at extreme concentrations. We observe that NTs from different spidroins have co-evolved with their respective repeat region, and now use an NT that is distantly related to previously used NTs, for efficient recombinant production of the amyloid-β peptide (Aβ) implicated in Alzheimer’s disease. A designed variant of NT from Nephila clavipes flagelliform spidroin, which in nature allows production and storage of β-hairpin repeat segments, gives exceptionally high yields of different human Aβ variants as a solubility tag. This tool enables efficient production of target peptides also in minimal medium and gives up to 10 times more isotope-labeled monomeric Aβ peptides per liter bacterial culture than previously reported.

Experimental and mathematical optimization of the peroxide delignification of larch in the presence of MnSO4 catalyst

2020 ◽  
Vol 20 (1) ◽  
pp. 67-75
Author(s):  
I. G. Sudakova ◽  
N. V. Garyntseva ◽  
A. I. Chudina ◽  
B. N. Kuznetsov
Keyword(s):  
Mathematical Optimization ◽  
Single Step ◽  
High Yield ◽  
Optimal Conditions ◽  
Optimal Parameters ◽  
Mathematical Methods ◽  
Catalytic Method ◽  
Mild Conditions ◽  
Xrd Studies ◽  
Peroxide Delignification

Experimental and mathematical methods were used to obtain the optimal parameters of peroxide delignification of larch in the presence of MnSO4 catalyst, which provide a high yield of cellulose (44.3 wt.%) with a low content of residual lignin: temperature 100 °C, content of H2O2 6 wt.%, CH3COOH 25 wt.%, hydromodulus 15, and duration 3 h. The cellulose produced under optimal conditions had the following chemical composition: cellulose 92.7 wt.%, lignin 0.6 wt.%, and hemicellulose 5.7 wt.%. IR spectroscopy and XRD studies revealed that the structure of cellulose produced from larch is similar to that of industrial microcrystalline cellulose. The proposed catalytic method allows obtaining larch-derived cellulose with a minimum content of lignin under mild conditions in a single step with a high yield, crystallinity 0.8 and crystallite size 3.0 nm.

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