Continuous cultivation of bakers' yeast: Change in cell composition at different dilution rates and effect of heat stress on trehalose level

Ertugay, N
Hamamcı, Haluk
The cell composition of bakers' yeast in a continuous culture was determined for different dilution rates. Also, the cellular response to heat stress in terms of trehalose, RNA, glycogen and protein was determined at a specified dilution rate of 0.1/h. The amount of storage saccharides, trehalose and glycogen, was found to decrease whereas the amount of RNA and protein increased with increasing dilution rates. As the dilution rate was increased from 0.1 to 0.4/h at 0.05 intervals the steady-state trehalose content decreased from 33 to 8.6 mg/g biomass, and glycogen content from 150 to 93 mg/g biomass. On the other hand, the protein content increased from 420 to 530 mg/g biomass and the RNA content from 93 to 113 mg/g biomass. Heat stress was applied by increasing the medium temperature from 30 to 36, 38 or 40 degrees C at constant dilution rates. The highest amount of trehalose accumulation, 108 mg/g biomass, was achieved when heat stress at 38 degrees C was applied. The protein content, on the other hand, decreased from 350 to 325 mg/g biomass at the end of the experiment.


Poly(hydroxybutyrate-co-hydroxyvalerate) nanocapsules as enzyme carriers for cancer therapy: an in vitro study
Baran, ET; Ozer, N; Hasırcı, Vasıf Nejat (2002-05-01)
In the present paper, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanocapsules were prepared by a double emulsion-solvent evaporation procedure (w/o/w) for the encapsulation of model enzymes (L-asparaginase, catalase, glucose oxidase) and bovine serum albumin. To increase the encapsulation efficiency and activity of the encapsulated enzyme, numerous modifications were made in the compositions of the phases of double emulsion. For the preparation of low molecular weight PHBV, the polymer was treated with so...
Optimising clarification of carrot juice by bacterial crude pectinase
Uzuner, Sibel; Çekmecelioğlu, Deniz (2015-12-01)
This study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box-Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL(-1)) at different concentrations (0.1-0.5%), pH (4-7), and time (2-6 h). The obtained enzyme was also compared with commercial fungal pectinase at...
Mechanical and biochemical characterisation of wheat gluten films as a function of pH and co-solvent
Kayserilioglu, BS; Stevels, WM; Mulder, WJ; Akkas, N (Wiley, 2001-08-01)
Dispersions of wheat gluten were prepared at different pHs (4, 6 and 11) in the presence or absence of ethanol. Films were obtained after casting suspensions followed by evaporation of the solvent. Films prepared at pH 11 were significantly stronger than the films prepared at pH 4 and 6 with tensile strengths of approximately 7 vs. 2 MPa. With increasing strength, the elongation at break was moderately reduced from approximately 300% to 190%. No significant variations of water vapour transfer rate propertie...
Experimental investigation of particle filtration in compression resin transfer molding of advanced composites
Aydil Dalkıran, Tuğçe; Erdal Erdoğmuş, Merve; Department of Mechanical Engineering (2014)
With the inclusion of particle fillers in advanced continuous fiber reinforced composites, issues such as impregnation with increased viscosity of the injected resin leading to high process pressures and possible nonhomogeneous/directional composite properties due to filtering of filler particles necessitate the study of the relations between processing parameters and the resulting particle distributions. In this study, the particle-resin interaction during compression resin transfer molding (CRTM) and resi...
Kinetic analysis of aspergillus oryzae cultivations on starch
Bayındırlı, Alev; UNGAN, S (Informa UK Limited, 1991-01-01)
Cultivation of Aspergillus oryzae on starch is described as a combination of two rate processes: Starch hydrolysis and the cellular activities of the fungi including growth, enzyme production and maintenance. Kinetic models are presented to describe growth, enzyme production, starch hydrolysis and uptake of the hydrolysis products. Numerical values of the model parameters indicated that the rate controlling step of A. oryzae growth on starch was not starch hydrolysis, but the substrate uptake process. Gluco...
Citation Formats
N. Ertugay and H. Hamamcı, “Continuous cultivation of bakers’ yeast: Change in cell composition at different dilution rates and effect of heat stress on trehalose level,” FOLIA MICROBIOLOGICA, pp. 463–467, 1997, Accessed: 00, 2020. [Online]. Available: