scholarly journals New Biotransformation Process for Production of the Fragrant Compound γ-Dodecalactone from 10-Hydroxystearate by Permeabilized Waltomyces lipofer Cells

2013 ◽  
Vol 79 (8) ◽  
pp. 2636-2641 ◽  
Author(s):  
Jung-Ung An ◽  
Young-Chul Joo ◽  
Deok-Kun Oh
Keyword(s):  
Oleaginous Yeast ◽  
Reaction Conditions ◽  
Conversion Yield ◽  
Content Type ◽  
Permeabilized Cells ◽  
Yeast Strains ◽  
Biotransformation Process ◽  
Sequential Treatments ◽  
Triton X ◽  
Optimal Reaction

ABSTRACTA new biotransformation process for the production of the flavor lactone was developed by using permeabilizedWaltomyces lipofer, which was selected as an efficient γ-dodecalactone-producing yeast among 10 oleaginous yeast strains. The optimal reaction conditions for γ-dodecalactone production by permeabilizedW. lipofercells were pH 6.5, 35°C, 200 rpm, 0.7 M Tris, 60 g/liter of 10-hydroxystearic acid, and 30 g/liter of cells. Under these conditions, nonpermeabilized cells produced 12 g/liter of γ-dodecalactone after 30 h, with a conversion yield of 21% (wt/wt) and a productivity of 0.4 g/liter/h, whereas permeabilized cells obtained after sequential treatments with 50% ethanol and 0.5% Triton X-100 produced 46 g/liter of γ-dodecalactone after 30 h, with a conversion yield of 76% (wt/wt) and a productivity of 1.5 g/liter/h. These values were 3.7- and 3.8-fold higher than those obtained using nonpermeabilized cells. These are the highest reported concentration, conversion yield, and productivity for the production of the bioflavor lactone.

scholarly journals Enrichment of Polyglucosylated Isoflavones from Soybean Isoflavone Aglycones Using Optimized Amylosucrase Transglycosylation

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 181 ◽  
Author(s):  
Young Sung Jung ◽  
Ye-Jin Kim ◽  
Aaron Taehwan Kim ◽  
Davin Jang ◽  
Mi-Seon Kim ◽  
...  
Keyword(s):  
Soy Isoflavones ◽  
Reaction Conditions ◽  
Conversion Yield ◽  
Solubility In Water ◽  
Soybean Extract ◽  
Deinococcus Geothermalis ◽  
High Conversion Yield ◽  
Processing And Storage ◽  
And Storage ◽  
Optimal Reaction

Isoflavones in soybeans are well-known phytoestrogens. Soy isoflavones present in conjugated forms are converted to aglycone forms during processing and storage. Isoflavone aglycones (IFAs) of soybeans in human diets have poor solubility in water, resulting in low bioavailability and bioactivity. Enzyme-mediated glycosylation is an efficient and environmentally friendly way to modify the physicochemical properties of soy IFAs. In this study, we determined the optimal reaction conditions for Deinococcus geothermalis amylosucrase-mediated α-1,4 glycosylation of IFA-rich soybean extract to improve the bioaccessibility of IFAs. The conversion yields of soy IFAs were in decreasing order as follows: genistein > daidzein > glycitein. An enzyme quantity of 5 U and donor:acceptor ratios of 1000:1 (glycitein) and 400:1 (daidzein and genistein) resulted in high conversion yield (average 95.7%). These optimal reaction conditions for transglycosylation can be used to obtain transglycosylated IFA-rich functional ingredients from soybeans.

scholarly journals Behaviors and Energy Source of Mycoplasma gallisepticum Gliding

2019 ◽  
Vol 201 (19) ◽  
Author(s):  
Masaki Mizutani ◽  
Makoto Miyata
Keyword(s):  
Energy Source ◽  
Mycoplasma Pneumoniae ◽  
Mycoplasma Gallisepticum ◽  
Gliding Motility ◽  
Influenza Viruses ◽  
Cell Axis ◽  
Content Type ◽  
Permeabilized Cells ◽  
Direct Energy ◽  
Triton X

ABSTRACT Mycoplasma gallisepticum, an avian-pathogenic bacterium, glides on host tissue surfaces by using a common motility system with Mycoplasma pneumoniae. In the present study, we observed and analyzed the gliding behaviors of M. gallisepticum in detail by using optical microscopes. M. gallisepticum glided at a speed of 0.27 ± 0.09 μm/s with directional changes relative to the cell axis of 0.6 degree ± 44.6 degrees/5 s without the rolling of the cell body. To examine the effects of viscosity on gliding, we analyzed the gliding behaviors under viscous environments. The gliding speed was constant in various concentrations of methylcellulose but was affected by Ficoll. To investigate the relationship between binding and gliding, we analyzed the inhibitory effects of sialyllactose on binding and gliding. The binding and gliding speed sigmoidally decreased with sialyllactose concentration, indicating the cooperative binding of the cell. To determine the direct energy source of gliding, we used a membrane-permeabilized ghost model. We permeabilized M. gallisepticum cells with Triton X-100 or Triton X-100 containing ATP and analyzed the gliding of permeabilized cells. The cells permeabilized with Triton X-100 did not show gliding; in contrast, the cells permeabilized with Triton X-100 containing ATP showed gliding at a speed of 0.014 ± 0.007 μm/s. These results indicate that the direct energy source for the gliding motility of M. gallisepticum is ATP. IMPORTANCE Mycoplasmas, the smallest bacteria, are parasitic and occasionally commensal. Mycoplasma gallisepticum is related to human-pathogenic mycoplasmas—Mycoplasma pneumoniae and Mycoplasma genitalium—which cause so-called “walking pneumonia” and nongonococcal urethritis, respectively. These mycoplasmas trap sialylated oligosaccharides, which are common targets among influenza viruses, on host trachea or urinary tract surfaces and glide to enlarge the infected areas. Interestingly, this gliding motility is not related to other bacterial motilities or eukaryotic motilities. Here, we quantitatively analyze cell behaviors in gliding and clarify the direct energy source. The results provide clues for elucidating this unique motility mechanism.

Synthesis of Phosphonates via Michaelis-Arbuzov Reaction

2017 ◽  
Vol 14 (6) ◽  
pp. 883-903 ◽  
Author(s):  
Boppudi Hari Babu ◽  
Gandavaram Syam Prasad ◽  
Chamarthi Naga Raju ◽  
Mandava Venkata Basaveswara Rao
Keyword(s):  
Reaction Times ◽  
Biologically Active ◽  
Fine Tuning ◽  
Arbuzov Reaction ◽  
Reaction Conditions ◽  
Solvent Type ◽  
Potential Applications ◽  
Synthetic Methodologies ◽  
Optimal Reaction ◽  
The Arbuzov Reaction

Background: Michaelis–Arbuzov reaction has played a key role for the synthesis of dialkyl or diaryl phosphonates by reacting various alkyl or aryl halides with trialkyl or triaryl phosphite. This reaction is very versatile in the formation of P-C bond from the reaction of aliphatic halides with phosphinites or phosphites to yield phosphonates, phosphinates, phosphine oxides. The Arbuzov reaction developed some methodologies, possible mechanistic pathways, selectivity, potential applications and biologically active various phosphonates. Objective: The synthesis of phosphonates via Michaelis–Arbuzov reaction with many new and fascinating methodologies were developed and disclosed in the literature, and these are explored in this review. Conclusion: This review has discussed past developments and vast potential applications of Arbuzov reaction in the synthesis of organophosphonates. As presented in this review, various synthetic methodologies were developed to prepare a large variety of phosphonates. Improvements in the reaction conditions of Lewis-acid mediated Arbuzov rearrangement as well as the development of MW-assisted Arbuzov rearrangement were discussed. Finally, to achieve high selectivities and yields, fine-tuning of reaction conditions including solvent type, temperature, and optimal reaction times to be considered.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

scholarly journals A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Zhanzhi Liu ◽  
Ying Li ◽  
Jing Wu ◽  
Sheng Chen
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Optimal Temperature ◽  
Reaction Conditions ◽  
Enzymatic Production ◽  
Physiological Properties ◽  
Potential Applications ◽  
Kinetics Of ◽  
Optimal Reaction ◽  
Gene Age

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.

scholarly journals Efficient Degradation of Mordant Blue 9 Using the Fenton-Activated Persulfate System

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2532 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Felix Y. Telegin ◽  
Yingjie Cai ◽  
Dongsheng Xia ◽  
Tiziano Zarra ◽  
...  
Keyword(s):  
Butyl Alcohol ◽  
Textile Dye ◽  
Oh Radicals ◽  
Operational Parameters ◽  
Reaction Conditions ◽  
Tert Butyl Alcohol ◽  
Initial Ph ◽  
Fe Complex ◽  
Optimal Reaction ◽  
Activated Persulfate

In this study, a Fenton-activated persulfate (Fe2+/PS) system was introduced for the efficient degradation of Mordant Blue 9 (MB 9) as a textile dye in an aqueous solution. Results showed that the degradation of MB 9 was markedly influenced by operational parameters, such as initial pH, PS concentration, Fe2+ concentration, and initial dye concentration. Optimal reaction conditions were then determined. Inorganic anions, such as Cl− and HCO3−, enhanced the degradation efficiency of MB 9 under optimal conditions. Addition of HCO3− reduced the degradation performance of MB 9, whereas the addition of Cl− increased the degradation percentage of MB 9. In addition, quenching experiments were conducted using methanol and tert-butyl alcohol as scavengers, and methanol was identified as an effective scavenger. Thus, the degradation of MB 9 was attributed to S O 4 • − and •OH radicals. The degradation and mineralization efficiency of MB 9 was significantly reduced using the conventional Fenton process i.e., Fe2+/ hydrogen peroxide (HP) because of the formation of a Fe complex during degradation. Meanwhile, the Fe2+/persulfate (PS) system improved the degradation and mineralization performance.

scholarly journals Software-guided microscale flow calorimeter for efficient acquisition of thermokinetic data

2021 ◽  
Author(s):  
Timothy Aljoscha Frede ◽  
Marlene Dietz ◽  
Norbert Kockmann
Keyword(s):  
Design Of Experiments ◽  
Process Development ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Flow Calorimeter ◽  
Microscale Flow ◽  
Increased Sensitivity ◽  
Important Time ◽  
Optimal Reaction

AbstractFast chemical process development is inevitably linked to an optimized determination of thermokinetic data of chemical reactions. A miniaturized flow calorimeter enables increased sensitivity when examining small amounts of reactants in a short time compared to traditional batch equipment. Therefore, a methodology to determine optimal reaction conditions for calorimetric measurement experiments was developed and is presented in this contribution. Within the methodology, short-cut calculations are supplemented by computational fluid dynamics (CFD) simulations for a better representation of the hydrodynamics within the microreactor. This approach leads to the effective design of experiments. Unfavourable experimental conditions for kinetics experiments are determined in advance and therefore, need not to be considered during design of experiments. The methodology is tested for an instantaneous acid-base reaction. Good agreement of simulations was obtained with experimental data. Thus, the prediction of the hydrodynamics is enabled and the first steps towards a digital twin of the calorimeter are performed. The flow rates proposed by the methodology are tested for the determination of reaction enthalpy and showed that reasonable experimental settings resulted. Graphical abstract A methodology is suggested to evaluate optimal reaction conditions for efficientacquisition of kinetic data. The experimental design space is limited by thestepwise determination of important time scales based on specified input data.

scholarly journals Novel Tandem Biotransformation Process for the Biosynthesis of a Novel Compound, 4-(2,3,5,6-Tetramethylpyrazine-1)-4′-Demethylepipodophyllotoxin

2011 ◽  
Vol 77 (9) ◽  
pp. 3023-3034 ◽  
Author(s):  
Ya-Jie Tang ◽  
Wei Zhao ◽  
Hong-Mei Li
Keyword(s):  
Cell Line ◽  
Alternaria Alternata ◽  
Water Solubility ◽  
Tumor Cell Line ◽  
Gibberella Fujikuroi ◽  
Hydroxyl Group ◽  
Epithelial Cell Line ◽  
The Novel ◽  
Content Type ◽  
Biotransformation Process

ABSTRACTAccording to the structure of podophyllotoxin and its structure-function relationship, a novel tandem biotransformation process was developed for the directional modification of the podophyllotoxin structure to directionally synthesize a novel compound, 4-(2,3,5,6-tetramethylpyrazine-1)-4′-demethylepipodophyllotoxin (4-TMP-DMEP). In this novel tandem biotransformation process, the starting substrate of podophyllotoxin was biotransformed into 4′-demethylepipodophyllotoxin (product 1) with the demethylation of the methoxyl group at the 4′ position byGibberella fujikuroiSH-f13, which was screened out from Shennongjia prime forest humus soil (Hubei, China). 4′-Demethylepipodophyllotoxin (product 1) was then biotransformed into 4′-demethylpodophyllotoxone (product 2) with the oxidation of the hydroxyl group at the 4 position byAlternaria alternataS-f6, which was screened out from the gatheredDysosma versipellisplants in the Wuhan Botanical Garden, Chinese Academy of Sciences. Finally, 4′-demethylpodophyllotoxone (product 2) and ligustrazine were linked with a transamination reaction to synthesize the target product 4-TMP-DMEP (product 3) byAlternaria alternataS-f6. Compared with podophyllotoxin (i.e., a 50% effective concentration [EC50] of 529 μM), the EC50of 4-TMP-DMEP against the tumor cell line BGC-823 (i.e., 0.11 μM) was significantly reduced by 5,199 times. Simultaneously, the EC50of 4-TMP-DMEP against the normal human proximal tubular epithelial cell line HK-2 (i.e., 0.40 μM) was 66 times higher than that of podophyllotoxin (i.e., 0.006 μM). Furthermore, compared with podophyllotoxin (i.e., logP= 0.34), the water solubility of 4-TMP-DMEP (i.e., logP= 0.66) was significantly enhanced by 94%. For the first time, the novel compound 4-TMP-DMEP with superior antitumor activity was directionally synthesized from podophyllotoxin by the novel tandem biotransformation process developed in this work.

scholarly journals Snf1 Is a Regulator of Lipid Accumulation in Yarrowia lipolytica

2013 ◽  
Vol 79 (23) ◽  
pp. 7360-7370 ◽  
Author(s):  
John Seip ◽  
Raymond Jackson ◽  
Hongxian He ◽  
Quinn Zhu ◽  
Seung-Pyo Hong
Keyword(s):  
Yarrowia Lipolytica ◽  
Lipid Accumulation ◽  
Oleaginous Yeast ◽  
De Novo ◽  
Lipid Synthesis ◽  
Omega 3 ◽  
Wild Type ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Dry Cell Weight

ABSTRACTIn the oleaginous yeastYarrowia lipolytica,de novolipid synthesis and accumulation are induced under conditions of nitrogen limitation (or a high carbon-to-nitrogen ratio). The regulatory pathway responsible for this induction has not been identified. Here we report that the SNF1 pathway plays a key role in the transition from the growth phase to the oleaginous phase inY. lipolytica. Strains with aY. lipolyticasnf1(Ylsnf1) deletion accumulated fatty acids constitutively at levels up to 2.6-fold higher than those of the wild type. When introduced into aY. lipolyticastrain engineered to produce omega-3 eicosapentaenoic acid (EPA),Ylsnf1deletion led to a 52% increase in EPA titers (7.6% of dry cell weight) over the control. Other components of theY. lipolyticaSNF1 pathway were also identified, and their function in limiting fatty acid accumulation is suggested by gene deletion analyses. Deletion of the gene encoding YlSnf4, YlGal83, or YlSak1 significantly increased lipid accumulation in both growth and oleaginous phases compared to the wild type. Furthermore, microarray and quantitative reverse transcription-PCR (qRT-PCR) analyses of theYlsnf1mutant identified significantly differentially expressed genes duringde novolipid synthesis and accumulation inY. lipolytica. Gene ontology analysis found that these genes were highly enriched with genes involved in lipid metabolism. This work presents a new role for Snf1/AMP-activated protein kinase (AMPK) pathways in lipid accumulation in this oleaginous yeast.

scholarly journals Synthesis of propylene carbonate from urea and 1,2-propylene glycol over metal carbonates

2011 ◽  
Vol 17 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Jiancheng Zhou ◽  
Wu Dongfang ◽  
Birong Zhang ◽  
Yali Guo
Keyword(s):  
Reaction Time ◽  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Reaction Temperature ◽  
Reaction Conditions ◽  
Lead Carbonate ◽  
Synthetic Process ◽  
Metal Carbonates ◽  
Optimal Reaction ◽  
Mixed Carbonate

A series of single-metal carbonates and Pb-Zn mixed-metal carbonates were prepared as catalysts for alcoholysis of urea with 1,2-propylene glycol (PG) for the synthesis of propylene carbonate (PC). The mixed carbonates all show much better catalytic activities than the single carbonates, arising from a strong synergistic effect between the two crystalline phases, hydrozincite and lead carbonate. The mixed carbonate with Pb/Zn=1:2 gives the highest yield of PC, followed by the mixed carbonate with Pb/Zn=1:3. Furthermore, Taguchi method was used to optimize the synthetic process for improving the yield of PC. It is shown that the reaction temperature is the most significant factor affecting the yield of PC, followed by the reaction time, and that the optimal reaction conditions are the reaction time at 5 hours, the reaction temperature at 180 oC and the catalyst amount at 1.8 wt%, resulting in the highest PC yield of 96.3%.

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