scholarly journals Effect of low temperatures on amounts of sulfur compounds accumulated in yeast cells and the activity of methionine adenosyl transferase during moromi-mash and in parallel fermentation media

2006 ◽  
Vol 101 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Hitoshi SHINDO ◽  
Shuhei YABE ◽  
Toshitaka KAKUTA ◽  
Takeo KOIZUMI
Keyword(s):  
Low Temperatures ◽  
Sulfur Compounds ◽  
Yeast Cells ◽  
Fermentation Media ◽  
Methionine Adenosyl Transferase

The Nature of Vulcanization Part IV

1929 ◽  
Vol 2 (3) ◽  
pp. 421-430
Author(s):  
H. P. Stevens ◽  
W. H. Stevens
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Hydrochloric Acid ◽  
Zinc Sulfide ◽  
Low Temperatures ◽  
Sulfur Compounds ◽  
Zinc Salt ◽  
Acetone Vapor ◽  
Volatile Sulfur Compounds ◽  
Ether Mixture

Abstract (1) At low temperatures by means of accelerators it is possible to produce vulcanites containing “combined sulfur” considerably in excess of that required for the formula C5H8S. Such vulcanites may be obtained by vulcanizing at 100° with a variety of ultra-accelerators with and without zinc oxide as an activator. If zinc oxide or a zinc salt is used the excess coefficient cannot be explained by the presence of the zinc sulfide in the vulcanite. (2) The amount of sulfur combined with the rubber, given sufficient heating and presence of accelerator, is mainly dependent on the excess of sulfur present. (3) Extraction of the vulcanite with hydrochloric acid-ether mixture removes a part of the “combined” sulfur. A considerable amount is removed when the amount of combined sulfur is very large, but even then the amount of sulfur remaining is considerably in excess of that required by the formula C5H8S. (4) Vulcanization at low temperatures in solution in accordance with Whitby's procedure with the aid of accelerators also yields vulcanites with coefficients in excess of that required for the formula C5H8S. (5) The result of vulcanization at low temperatures is approximately the same, whether the rubber contains all the protein and serum ingredients, the usual proportion, or very little. (6) Extraction of sulfur from vulcanite with hot acetone vapor is not complete after 1210 hrs. (7) Having regard to the hydrogen sulfide and other volatile sulfur compounds evolved in appreciable quantities during vulcanization, it is evident that part of the combined sulfur results from substitution of hydrogen by sulfur. This substituted product is decomposed by the hydrochloric acid-ether mixture. It may not be possible to decompose the whole in this manner. Consequently, any “combined” sulfur in excess of that required by the formula C5H8S may result from substitution in the molecule.

scholarly journals Entrapped Psychrotolerant Yeast Cells within Pine Sawdust for Low Temperature Wine Making: Impact on Wine Quality

2020 ◽  
Vol 8 (5) ◽  
pp. 764 ◽  
Author(s):  
Antonia Terpou ◽  
Vassilios Ganatsios ◽  
Maria Kanellaki ◽  
Athanasios A. Koutinas
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Solid Phase ◽  
Yeast Cells ◽  
Volatile Fraction ◽  
Pine Sawdust ◽  
Fermentation Efficiency ◽  
Freeze Dried ◽  
Immobilized Biocatalyst ◽  
Psychrotolerant Yeast

An alternative methodology is proposed for low temperature winemaking using freeze-dried raw materials. Pine sawdust was delignified and the received porous cellulosic material was applied as immobilization carrier of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1. The immobilization of yeast cells was examined and verified by scanning electron microscopy (SEM). The immobilized biocatalyst and high-gravity grape must were separately freeze-dried without cryoprotectants and stored at room temperature (20–22 °C) for 3 months. The effect of storage on the fermentation efficiency of the immobilized biocatalyst at low temperatures (1–10 °C), as well as on the aromatic characteristics of the produced wines was evaluated. Storage time had no significant effect on the fermentation efficiency of the biocatalyst resulting in most cases in high ethanol production 13.8–14.8% v/v. The volatile fraction of the produced wines was examined using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography mass spectrometry (GC/MS). GC-MS/SPME analysis along with the organoleptic evaluation revealed in all produced wines a plethora of fresh and fruit aromatic notes. To conclude, fermentation kinetics and aromatic profile evaluation encourages the production of high-quality sweet wines at low temperatures using pine sawdust (Pinus halepensis) entrapped yeast cells as a promoter.

scholarly journals Methionine and Glycine Stabilize Mitochondrial Activity in Sake Yeast During Ethanol Fermentation

2019 ◽  
Vol 57 (4) ◽  
pp. 535-543
Author(s):  
Ferdouse Jannatul ◽  
Yuki Kusaba ◽  
Yuki Fujimaru ◽  
Yuki Yamamoto ◽  
Hiroshi Kitagaki
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acids ◽  
Ethanol Fermentation ◽  
Reactive Oxygen ◽  
Yeast Cells ◽  
Mitochondrial Activity ◽  
Oxygen Species ◽  
Brewer’S Yeasts ◽  
Fermentation Media

Addition of amino acids to fermentation media affects the growth and brewing profiles of yeast. In addition, retaining mitochondrial activity during fermentation is critical for the fermentation profiles of brewer’s yeasts. However, a concrete mechanism linking amino acids in fermentation media with mitochondrial activity during fermentation of brewer’s yeasts is yet unknown. Here, we report that amino acids in fermentation media, especially methionine (Met) and glycine (Gly), stabilize mitochondrial activity during fermentation of sake yeast. By utilizing atg32Δ mutant sake yeast, which shows deteriorated mitochondrial activity, we screened candidate amino acids that strengthened the mitochondrial activity of sake yeast during fermentation. We identified Met and Gly as candidate amino acids that fortify mitochondrial activity in sake yeast during fermentation. To confirm this biochemically, we measured reactive oxygen species (ROS) levels in sake yeast fermented with Met and Gly. Yeast cells supplemented with Met and Gly retained high ROS levels relative to the non-supplemented sake yeast. Moreover, Met-supplemented cells showed a metabolome distinct from that of non-supplemented cells. These results indicate that specific amino acids such as Met and Gly stabilize the mitochondrial activity of sake yeast during fermentation and thus manipulate brewing profiles of yeast.

scholarly journals Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer’s Research

2019 ◽  
Vol 20 (14) ◽  
pp. 3595 ◽  
Author(s):  
Salman Ali Al-Ahdal ◽  
Aminuddin Bin Ahmad Kayani ◽  
Mohd Anuar Md Ali ◽  
Jun Yuan Chan ◽  
Talal Ali ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
High Frequency ◽  
Low Temperatures ◽  
Electrode Array ◽  
Transformation Process ◽  
Yeast Cells ◽  
Negative Change ◽  
Beta Proteins ◽  
Higher Temperature ◽  
Amyloid Beta Proteins

We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aβ) in a microfluidic environment. The Aβ was separated from the cells and characterized using the gradual dissolution of Aβ as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aβ under specific dielectrophoretic parameters. Further, Aβ in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aβ fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aβ to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aβ-related colloidal microfluidic research and could be applied to Alzheimer’s research in the future.

scholarly journals Dehydration of fructose, sucrose and inulin to 5-hydroxymethylfurfural over yeast-derived carbonaceous microspheres at low temperatures

RSC Advances ◽  
2019 ◽  
Vol 9 (16) ◽  
pp. 9041-9048 ◽  
Author(s):  
Xiaofeng Li ◽  
Yi Wang ◽  
Xiaomin Xie ◽  
Changhong Huang ◽  
Sen Yang
Keyword(s):  
Sulphuric Acid ◽  
Low Temperatures ◽  
Room Temperature ◽  
Hydrothermal Carbonization ◽  
Yeast Cells

This work prepared carbonaceous microspheres by hydrothermal carbonization of yeast cells followed by sulfonation with concentrated sulphuric acid (98%) at room temperature.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

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