Effect of Choline Acetate on the Yeast Cells During Fermentation: Kinetics Approach

2020 ◽  
Vol 6 (3) ◽  
pp. 172-179
Author(s):  
Amal A. Elgharbawy ◽  
Md. Zahangir Alam ◽  
Muhammad Moniruzzaman ◽  
Nassereldeen A. Kabbashi ◽  
Parveen Jamal ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Specific Growth ◽  
Cell Number ◽  
Control Culture ◽  
Yeast Cells ◽  
Green Solvents ◽  
Yeast Extract Peptone Dextrose ◽  
Kinetic Growth ◽  
Hydrolysis Process ◽  
Specific Growth Rates

Background: Ionic liquids (ILs) are claimed as green solvents and have demonstrated ability in the dissolution of several biomaterials and polymers, thus promoting their applications in wide scope. The aim of this study was to evaluate the yeast cells in the ionic liquid (IL), choline acetate [Cho]OAc as an eco-friendlier IL for their growth and ability of fermentation of the empty fruit bunch (EFB) biomass for ethanol production via monitoring the cell growth curve and kinetics. Methods: The Saccharomyces cerevisiae was cultured for five days on yeast extract-peptone-dextrose (YPD) agar and the sub-culturing was carried out every two weeks to evaluate the growth of yeast in [Cho]OAc at different concentrations; 5%, 10%, and 20%, where it was pre-cultivated for 24 h at 30 °C and 150 rpm in a shaking incubator as a control culture. Yeast cell number was determined by counting using a hemocytometer. Also, the kinetic growth of yeast during the fermentation of EFB was evaluated. Result: Cell concentration increased, ethanol production increased along with the optical density with the peak reached at 72 h, then declined. Enzymatic hydrolysis process followed by fermentation of EFB using [Cho][OAc] improved the yield of sugar, saccharification and ethanol around 1.938, 2.879, and 2.165 times in comparison with untreated EFB with IL. Furthermore, values of specific growth rates obtained in IL-medium and non-IL-medium are applicable for ethanol production to take place. The results showed the ability of yeast cells for fermentation even in the presence of IL. Conclusion: The results showed that the presence of the IL did not suppress the growth of the yeast cells and did not impair the fermentation productivity.

scholarly journals Effect of Specific Growth Rate on Fermentative Capacity of Baker’s Yeast

1998 ◽  
Vol 64 (11) ◽  
pp. 4226-4233 ◽  
Author(s):  
Pim Van Hoek ◽  
Johannes P. Van Dijken ◽  
Jack T. Pronk
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Ethanol Production ◽  
Growth Rates ◽  
Specific Growth ◽  
Pyruvate Decarboxylase ◽  
Baker's Yeast ◽  
Fermentative Capacity ◽  
Yeast Biomass ◽  
Specific Growth Rates

ABSTRACT The specific growth rate is a key control parameter in the industrial production of baker’s yeast. Nevertheless, quantitative data describing its effect on fermentative capacity are not available from the literature. In this study, the effect of the specific growth rate on the physiology and fermentative capacity of an industrialSaccharomyces cerevisiae strain in aerobic, glucose-limited chemostat cultures was investigated. At specific growth rates (dilution rates, D) below 0.28 h−1, glucose metabolism was fully respiratory. Above this dilution rate, respirofermentative metabolism set in, with ethanol production rates of up to 14 mmol of ethanol · g of biomass−1 · h−1at D = 0.40 h−1. A substantial fermentative capacity (assayed offline as ethanol production rate under anaerobic conditions) was found in cultures in which no ethanol was detectable (D < 0.28 h−1). This fermentative capacity increased with increasing dilution rates, from 10.0 mmol of ethanol · g of dry yeast biomass−1 · h−1 at D= 0.025 h−1 to 20.5 mmol of ethanol · g of dry yeast biomass−1 · h−1 atD = 0.28 h−1. At even higher dilution rates, the fermentative capacity showed only a small further increase, up to 22.0 mmol of ethanol · g of dry yeast biomass−1 · h−1 at D= 0.40 h−1. The activities of all glycolytic enzymes, pyruvate decarboxylase, and alcohol dehydrogenase were determined in cell extracts. Only the in vitro activities of pyruvate decarboxylase and phosphofructokinase showed a clear positive correlation with fermentative capacity. These enzymes are interesting targets for overexpression in attempts to improve the fermentative capacity of aerobic cultures grown at low specific growth rates.

scholarly journals EFFECTS OF DEPTH AND CONCENTRATION OF DIGESTATE ON GROWTH OF THREE MICROALGAL SPECIES

2016 ◽  
Vol 54 (5) ◽  
pp. 591 ◽  
Author(s):  
Nguyen Tran Thien Khanh
Keyword(s):  
Specific Growth ◽  
Low Cost ◽  
Middle Layer ◽  
Bottom Layer ◽  
Cell Number ◽  
Continuous Illumination ◽  
Microalgal Biomass ◽  
Specific Growth Rates ◽  
Counting Cell ◽  
Microalgal Species

In order to design a culture system for microalgal biomass production with a low cost and convenient cell collection, growth performance of mixtures of microalgal cells, including Euglena gracilis, Chlorella vulgaris, and Dunaliella tertiolecta cultured in a volume of 1 L were investigated at a PPFD of 300 µmol m-2 s-1 at the surface of the solution with continuous illumination at 30 °C. Each culture container contained diluted digestate at concentrations of 5, 10, 15, 20, and 50 %. Sample cells for counting cell number were collected daily at three depths: 0–50 mm (the surface layer), 10–15 mm (the middle layer), and 25–30 mm (the bottom layer). Pseudo-specific growth rates (ms) of each species at each depth were calculated as cellular multiplication rates using number of cells per time. In each layer, the average ms of each species was highest in 5 % digestate. The average ms of all three microalgal species (0.035 h-1) was observed in all layers in 5 % digestate solution. The ms of each species was highest in the bottom layer in 5% digestate (0.048 h-1, 0.041 h-1, and 0.022 h-1, respectively for C. vulgaris, E. gracilis, and D. tertiolecta). In conclusion, E. gracilis, C. vulgaris, and D. tertiolecta showed the highest specific growth rate in 5 % digestate in all layer.

Oscillating conditions for influencing the composition of mixed biological cultures

1998 ◽  
Vol 37 (4-5) ◽  
pp. 259-262 ◽  
Author(s):  
Bjarne R. Horntvedt ◽  
Morten Rambekk ◽  
Rune Bakke
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Heterotrophic Bacteria ◽  
Bacterial Species ◽  
Rate Reduction ◽  
Similar Strategy ◽  
Sinusoidal Oscillations ◽  
Specific Growth Rates ◽  
Rate Limiting ◽  
Concentration Levels

This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).

Effects of turbidity on prey consumption and growth in brook trout and implications for bioenergetics modeling

2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman
Keyword(s):  
Growth Rates ◽  
Brook Trout ◽  
Specific Growth ◽  
Abiotic Factors ◽  
Foraging Strategies ◽  
Turbid Water ◽  
Daily Consumption ◽  
Consumption Rates ◽  
The Difference ◽  
Specific Growth Rates

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.

Sex Ratio and Sex-Specific Growth Rates of Immature Green Turtles, Chelonia mydas, in the Southern Bahamas

Copeia ◽  
1992 ◽  
Vol 1992 (4) ◽  
pp. 1098 ◽  
Author(s):  
Alan B. Bolten ◽  
Karen A. Bjorndal ◽  
Janice S. Grumbles ◽  
David W. Owens
Keyword(s):  
Sex Ratio ◽  
Growth Rates ◽  
Specific Growth ◽  
Chelonia Mydas ◽  
Green Turtles ◽  
Specific Growth Rates

Physiological and cell morphology adaptation ofBacillus subtilisat near-zero specific growth rates: a transcriptome analysis

2014 ◽  
Vol 17 (2) ◽  
pp. 346-363 ◽  
Author(s):  
Wout Overkamp ◽  
Onur Ercan ◽  
Martijn Herber ◽  
Antonius J. A. van Maris ◽  
Michiel Kleerebezem ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Transcriptome Analysis ◽  
Growth Rates ◽  
Specific Growth ◽  
Specific Growth Rates

Cellulosic ethanol production by combination of cellulase-displaying yeast cells

2012 ◽  
Vol 51 (6-7) ◽  
pp. 366-372 ◽  
Author(s):  
Seung-Ho Baek ◽  
Sujin Kim ◽  
Kyusung Lee ◽  
Jung-Kul Lee ◽  
Ji-Sook Hahn
Keyword(s):  
Ethanol Production ◽  
Cellulosic Ethanol ◽  
Yeast Cells

Biology of Oscillatoria cf. chalybea, a 2-methylisoborneol producing blue-green alga of Mississippi catfish ponds

1995 ◽  
Vol 31 (11) ◽  
pp. 173-180 ◽  
Author(s):  
M. van der Ploeg ◽  
M. E. Dennis ◽  
M. Q. de Regt
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Light Availability ◽  
Continuous Light ◽  
Light Cycle ◽  
Blue Green Alga ◽  
Continuous Cultures ◽  
Effects Of Temperature ◽  
Catfish Ponds ◽  
Specific Growth Rates

Relative abundance of Oscillatoria cf. chalybea was monitored during May-November, 1993, in 40 ponds at four catfish farms located 50-100 km apart in west central Mississippi, USA. The occurrence of O. cf.chalybea coincided with the period that water temperatures remained above 20°C. In 70% of ponds, O. cf.chalybea was present for a period of 2-20 weeks. The alga recurred in all ponds where it had been present in 1990 and 1991. The effects of temperature and light availability on growth rate and 2-methylisoborneol (MIB) production of O. cf. chalybea were studied in continuous cultures. At 28°C, maximum specific growth rates were 0.8 d−1 (24 h light) and 0.6 d−1 (14 h light :10 h dark). Algal cells contained less MIB when adapted to the shorter light cycle than when grown under continuous light. Specific growth rate of O. cf.chalybea dropped from 0.3 to 0.1 d−1 when temperature was changed from 21 to 19.5°C (14 h light).

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).

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