Changes of respiration and of specific growth rate during cell cycle of yeast cells of different genealogical age

1988 ◽  
Vol 33 (2) ◽  
pp. 129-136 ◽  
Author(s):  
D. Vraná
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Yeast Cells

scholarly journals Influence of the specific growth rate on formation of sterols in yeast Saccharomyces cerevisiae during fed-batch cultivation

2000 ◽  
Vol 18 (No. 3) ◽  
pp. 110-114
Author(s):  
J. Čermák ◽  
M. Rychtera ◽  
P. Nechvíle ◽  
J. Náhlík ◽  
K. Melzoch ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Control Strategy ◽  
Respiratory Quotient ◽  
Specific Growth ◽  
Carbon Dioxide Concentration ◽  
Sterol Fraction ◽  
Yeast Cells ◽  
Dry Biomass

Ergosterol is a major sterol in yeast cells. Intermediates of ergosterol biosynthesis or products of ergosterol biotransformation occur in cells too. Sterols mainly form components of cell membranes. Fluidity of membranes is affected by sterols. The amount of sterols in cells can be influenced above all by cultivation conditions and by the yeast genotype. Specific growth rate is an important factor which affects the amount of sterols present in yeast cells. We carried out a series of 24-hour cultivations to find out the impact of specific growth rate on sterol biosynthesis. Inflow of synthetic medium to the bioreactor was controlled by means of a profile of carbon dioxide concentration in the outlet gases. This profile was acquired by simulation according to a mathematical model of cultivation. Profile of carbon dioxide concentration corresponded to a precalculated profile of specific growth rate. Cultivation was divided into two phases with different growth rate values. A constant value of the specific growth rate was maintained in the 1st phase. The specific growth rate value decreased by controlling the inflow in the 2nd phase (beginning at 12th hour of cultivation). Other cultivations were carried out using so-called physiological control which consisted in determining the immediate physiological state (e.g., RQ) and the choice of control strategy according to the metabolic state. Selected control strategy ensures an immediate action (inflow of the medium). If the specific growth rate decreased in the 1st phase, the amount of total sterols in yeast dry biomass increased (to 2.7% in yeast dry biomass). But the purity of ergosterol decreased (amount of sterol contaminants increased up to 23.3% in the sterol fraction). If a constant value of respiratory quotient was maintained (at about 1.1), the amount of total sterols in yeast dry biomass and the purity of ergosterol were constant. If the value of respiratory quotient was changed in the growth and final phase of cultivation, the amount of total sterols in yeast dry biomass increased (to 2.83% in yeast dry biomass). However, the purity of ergosterol decreased (amount of sterol contaminants increased up to 21.2% in sterol fraction).

scholarly journals Protatrans as biomodulators of Candida ethanolica growth

2020 ◽  
Vol 10 (3) ◽  
pp. 487-495
Author(s):  
A. S. Kiryukhina ◽  
T. S. Lozovaya ◽  
E. A. Privalova ◽  
V. G. Fedoseeva ◽  
E. N. Oborina ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Generation Time ◽  
Specific Growth ◽  
Optical Path Length ◽  
Ethanol Solution ◽  
Significant Part ◽  
Yeast Cells ◽  
Data Sets ◽  
S Curve

This study was aimed at investigating compounds from a series of protatranes as biostimulants for the growth of the Candida ethanolica yeast. The relevance of the study is associated with the need to determine conditions accelerating the growth of microorganisms in the presence of such highly effective, physiologically active and non-toxic compounds as protatranes. The research object was the Candida ethanolica yeast cultivated on a synthetic nutrient medium containing 1.5% ethanol solution as a carbon source. Protatrans were used at concentrations of 1·10-6 – 1·10-8 wt%. The number of yeast cells was controlled by determining the optical density of yeast suspensions using a KFK-3 Zomax photoelectrocolorimeter at a wavelength of 540 nm and optical path length of 10 mm. The determination of yeast biomass was carried out gravimetrically. The first stage of the work set out to study the accumulation of cells and biomass at various initial yeast cell concentrations. It was revealed that a slight increase in the initial concentration of yeast cells leads to a noticeable shift of the entire S-curve to the left. A comparison of the obtained data sets showed that the investigated protatranes significantly increase the specific growth rate and reduce the generation time during the log phase, provided that this phase accounts for a significant part of the cultivation process. However, the presence of protatranes significantly reduce the specific growth rate and increase the generation period in the log phase, provided that the culture remains in the stationary phase for a significant part of the cultivation time. This is likely to be associated with the positive effect of protatranes on protein synthesis, which is most intense during the log phase. The use of protatranes facilitates the control over the number of cells, amount of biomass, specific growth rate and generation time of the Candida ethanolica yeast depending on the initial cell concentration and, accordingly, the growth phase of the culture.

scholarly journals Feed demand behavior in sea bass juveniles: Effects on individual specific growth rate variation and health (inter-individual and inter-group variation)

Aquaculture ◽  
2008 ◽  
Vol 274 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. Millot ◽  
M.-L. Bégout ◽  
J. Person-Le Ruyet ◽  
G. Breuil ◽  
C. Di-Poï ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Sea Bass ◽  
Rate Variation ◽  
Group Variation

scholarly journals Control of the specific growth rate of Bacillus subtilis for the production of biosurfactant lipopeptides in bioreactors with foam overflow

2010 ◽  
Vol 45 (11) ◽  
pp. 1800-1807 ◽  
Author(s):  
S. Chenikher ◽  
J.S. Guez ◽  
F. Coutte ◽  
M. Pekpe ◽  
P. Jacques ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Specific Growth Rate ◽  
Specific Growth

E-beam irradiation affects the maximum specific growth rate ofBacillus cereus

2012 ◽  
Vol 48 (2) ◽  
pp. 382-386 ◽  
Author(s):  
Juan Aguirre ◽  
Mª Rosa Rodríguez ◽  
Rodrigo González ◽  
Gonzalo García de Fernando
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Beam Irradiation ◽  
Ofbacillus Cereus

Specific growth rate of Chlamydomonas reinhardtii and Chlorella sorokiniana under medium duration light/dark cycles: 13–87 s

1999 ◽  
Vol 70 (1-3) ◽  
pp. 323-333 ◽  
Author(s):  
Marcel Janssen ◽  
Tjibbe Chris Kuijpers ◽  
Bram Veldhoen ◽  
Michel Brik Ternbach ◽  
Johannes Tramper ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Chlamydomonas Reinhardtii ◽  
Specific Growth ◽  
Chlorella Sorokiniana
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