Settling kinetics of champagne yeast were studied with 0.01, 0.05, and 0.10 m NaCl, CaCl2, AlCl3, and 1.00 +/- 0.01 OD660 (optical density at 660 nm) initial yeast concentration at pH 1. In the suspensions with 0.01 M NaCl, the pH of the medium varied between 1 and 3, and the initial yeast concentration changed between 0.74 and 1.25 OD660. Analysis of the data showed that the settling phenomena occurred in two steps: (i) establishment of the diffuse double layer to overcome repulsion, hence achievement of cell-to-cell contact and specific bonding, and (ii) settling of the aggregates. The first stage of the settling phenomenon was described with a zero-order kinetic expression in yeast concentration. The second stage was described with a second-order expression. At pH 1 with 0.01 M concentration of all the salts, repulsion between the yeast cells decreased via reduction in the thickness of the diffuse double layer. Increasing the salt concentration to 0.05 or 0.10 m did not cause substantial change to the settling behavior with NaCl or CaCl2, but flocculation was inhibited because of the surface charge reversal with AlCl3. The first stage of the settling phenomenon was slower at pH 3.0, implying that the isoelectric point of the yeast surfaces was about 3.0.


Substrate interactions during the biodegradation of benzene, toluene and phenol mixtures
Abu Hamed, T; Bayraktar, E; Mehmetoglu, T; Mehmetoglu, U (Elsevier BV, 2003-09-30)
Benzene, toluene and phenol were degraded completely at high initial concentrations by Pseudomonas putida F I ATCC 700007. Two hundred and fifty milligram per litre benzene, 225 mg/l toluene and 200 mg/l phenol were degraded individually in 19, 14 and 3 5 h, respectively. The biodegradation times increased on increasing the substrate concentration. The maximum biodegradation rates were 149 mg benzene/g dry cell h for 60 mg/l benzene, 44 mg toluene/g dry cell h for 110 mg/l toluene and 102 mg phenol/g dry ce...
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The kinetics of riboflavin production by Saccharomyces cerevisiae and Saccharomyces carlsbergensis in synthetic media and wort were studied. The results indicated that riboflavin was produced by growing cells only. Riboflavin production rate was proportional to growth rate of the yeasts in the exponential phase. Riboflavin was depleted in the stationary phase. The depletion rate was expressed with a first-order kinetic expression in yeast concentration. The kinetics of substrate utilization and ethanol prod...
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The effects of surface properties on the rheological behavior of Aspergillus niger suspensions were studied at pH 2-7, with the addition of 0-0.10 m NaH2PO4, NaCl, CaCl2, AlCl3, and EDTA at shear rates of 0-21.6 s-1. The structural network concept was used to discuss the consequences of cell-cell interactions on the rheological behavior. Analysis of the data indicated that the suspensions containing CaCl2 nearly always had the smallest shear stress at all the pH values, indicating that, unlike with the yeas...
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The influence of methanol feeding rate on intracellular reaction network of recombinant human growth hormone (rhGH) producing Pichia pastoris was investigated at three different specific growth rates, namely, 0.02 (MS-0.02), 0.03 (MS-0.03), and 0.04h(-1) (MS-0.04) where Period-I (33 <= t < 42 h) includes the early exponential growth phase; Period-II (42 <= t < 48 h) is the exponential growth phase where the specific cell growth rate decreases; Period-III (48 <= t <= 51 h) is the exponential growth phase whe...
Mass flux balance-based model and metabolic pathway engineering analysis for serine alkaline protease synthesis by Bacillus licheniformis
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A mass flux balance-based stoichiometric model of Bacillus licheniformis for the serine alkaline protease (SAP) fermentation process has been established. The model considers 147 reaction fluxes, and there are 105 metabolites that are assumed to be in pseudo-steady state. Metabolic flux distributions were obtained from the solution of the model based on the minimum SAP accumulation rate assumption in B. licheniformis in combination with the off-line extracellular analyses of the metabolites that were the so...
Citation Formats
O. ARIKAN and M. OZILGEN, “SETTLING KINETICS OF CHAMPAGNE YEAST,” ENZYME AND MICROBIAL TECHNOLOGY, pp. 762–766, 1992, Accessed: 00, 2020. [Online]. Available: