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  • 1
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 3 (1983), S. 125-131 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fermentation kinetic, thermokinetic and morphological investigations of biological carbonsource conversions into microbial biomass and other reaction products can be used for improving the efficiency of biotechnical processes. In this way biorhythmic processes on a macrosocopic scale could be found in transitional stages of microorganism cultivation. These biorhythmic processes can be explained by the occurence of different cell states in the cell cycle. In order to characterize these cell states synchronized microorganism growth was investigated with the aid of the phased culture method. Two states could be observed in the case of yeast growth: the single cell state and the budding cell state. The duration and efficiency of the single cell state is dependent on the growth limitation and the carbon substrate feeding.Thus the reduction of carbon substrate feeding in states of synchronized populations which are characterized by a high percentage of single cells and by energy metabolite production which, in turn, is influenced by carbon substrate concentration can cause increased material and energetic efficiencies of biological carbon-source conversions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 12 (1992), S. 87-97 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Process control strategies, e.g. the steady-;state fermation, which do not consider the cell-;state distribution of cell populations, cause a decrease of yield coefficient connected to an increase of heat-;production coefficient.Contrary to this, the dynamic process control adapts the carbon-;substrate supply to the different repetitive cell-;population states during fermentation. In order to recognize the different states, the cell population is synchronized. The optimum period ofchanging carbon-;substrate supply was found to be dependent on the cell-;doubling time. Dynamic process control causes a higher yield coefficient as well as a lower heat-;production coefficient compared to the steady-;state fermentation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 12 (1992), S. 37-40 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new isolated Bacillus strain was cultivated continuously at 68°C and pH 3 for a long time. Extractable lipids represent about 3.6% of cell dry weight and are made up of 18% neutral lipids, 39.3% glycolipids, and 42% acidic lipids. Main components of the fatty acid fraction are ω-cyclohexylundecanoic acid and ω-cyclohexyltridecanoic acid, respectively. MK-7 and hop-22(29)-ene are components of the unsaponifiable fraction. The glycolipid fraction contains the pentacyclic triterpenoid tetrahydroxybacteriohopane.Based on the thermoacidophilic growth conditions, the morphologic and physiological properties, and the nature of lipids, it can assumed that the new isolated strain belongs to the species Bacillus acidocaldarius.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 12 (1992), S. 481-487 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The thermoacidophilic strain TAC1 was isolated from a sulphatara field. It grows heterotrophically on a synthetic medium, containing yeast extract and carbohydrates at 50 to 70°C and pH 2 to 5. The cells are motile spore-forming rods utilizing, for instance, glucose, lactose, or sucrose as carbon substrate. They also used concentrated whey as nutrient medium.The maximum specific growth rate calculated from batch culture data of the strain TAC1 on glucose is 0.9 h-1 at 65°C and pH 3. The yield coefficient determined in a chemostat culture of the strain TAC1 on glucose, is 0.15 to 0.31 grams of cells produced per gram of glucose consumed (63 to 70°C, pH 2.2 to 4.0, dilution rate 0.2 to 0.4 h-1).The lipid fraction extracted from the cells consists of 72 to 93% of ω-cyclohexyl C17 and C19 fatty acids. The composition of lipid fraction varied with the pH value and the dilution rate but not with the temperature.In regard to the morphology and physiology of the isolated strain as well as the high percentage of ω-cyclohexyl fatty acids of the cell material, the strain TAC1 is similar to Bacillus acidocaldarius.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 8 (1988), S. 435-444 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The experimental technique for measurement of microbial culture heat evolution directly in fermenter has been described and its correctness analysed. Heat-to-oxygen ratio, Q0, of synchronized yeast culture in the absence of fermentative metabolism has been found to be practically independent of a cell cycle phase and close to the theoretical constant predicted by the mass-energy balance theory. The collection of literature data on the heat-to-oxygen ratio is given. Energetic properties of cell biomass are discussed on the basis of the obtained and the surveyed values of Q0.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 4 (1984), S. 275-278 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adaptive feeding of nutrients especially of carbon and energy sources according to the demand of cells in different cell states during continuous or semicontinuous cultivation is called dynamic processing.The deduction of dynamic process control concepts is aimed at improving the efficiency of biological substrate conversions into cell mass and other reaction products.A growing number of results allows us to postulate that the principle of dynamic processing should be generally applied in biotechnical processes independent of the type of cells and substrates as well as the nature of products.The basis of the deduction of dynamic process control concepts is the exact knowledge of the dependences of efficiency and rate of product synthesis on cell states during the development of cell populations.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ethanol synthesis was initiated in aerobically pre-cultivated synchronized yeast populations by interrupting aeration and adding carbon substrate. Synchronization of yeast-cell functions was carried out by aerobic phased cultivation.Ethanol synthesis was more effective if it was closely connected with aerobic cell-mass synthesis and cell proliferation. Thus, anaerobic continuous ethanol production with cell recycling could be intensified by replacement of aged cells in single-cell state by aerobically pre-cultivated budding cells.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The strains E. coli C 600 and E. coli C 600 pL CR 665-58 were cultivated on a glucose containing nutrient medium. The cell states of the cell cycle were investigated by means of phased cultivation. The doubling time and the specific carbon-substrate consumption of cells were higher when E. coli C 600 pL CR 665-58 was used. During cell doubling cell states characterized by different specific carbon-substrate consumption coefficients were observed.By adaptation of carbon-substrates supply to the repetitive cell states during continuous cultivation of synchronized bacteria populations the efficiency of cell-mass production was increased by 15 percent.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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