The rate of dissolution and dehydration of C02 in a liquid model system was investigated. Components in the model system established the main conditions which may exist in the extracellular space of a microbiological culture liquid. The charge in voltage of a glass electrode was measured which indicated the formation of H+ ions in the H2C03The rate of CO, hydration increased with the increase of temperature from 0 to 40°C. Likewise the equilibrium of the reaction wss shifted towards the forward reaction. Similar results were observed when the tip velocity of the impeller was increased. Data suggest that agitation promotes the dissolution of COZ in the culture liquid through the reduction of gas-liquid film resistance in the diffusion of this gas. The rate of hydration of CO? into the bulk of the liquid was independent of pCOz above the surface of the liquid but depended on pC0z in the gas bubble within the liquid. The concentration of HCOS-was, furthermore, influenced by the buffer components, buffer capacity, and the viscosity of the system. Since pC02 and the HC03-concentration in the extracellular space depend on both physical and chemical factors, the ventilation of a culture liquid necewitates both exhaust of CO? from the ga. 4 bubbles of the culture broth and shift of the H&On : HC0,-+ H+ reaction towards the backward direction.HCOS-+ H+ reaction.
Abstract. Weaning performance of 10 808 purebred offsprings (4991 male and 5817 female) of 80 sires in 13 farms were analised using animal model. Heritability, breeding value, (co)variance components for weaning weight (WW), preweaning daily gain (PDG), 205-day weight (CWW) were calculated. Farm, parity, year of birth, season of birth, sex were treated as fixed, and the maternal permanent environment was treated as random effects. In case of WW and PDG, the age of the calves at weaning was fitted as a covariant. Data were analyzed with MTDFREML (Boldman et al. 1993) program. The overall mean value and standard deviation of WW, PDG and CWW were 221±47 kg, 1,111±0.21 kg/day and 226±42 kg, respectively. The age of the calves at weaning was 202 days. The direct heritability (h2d) of WW and PDG were 0.57±0.08, 0.49±0.07 and CWW was 0.44±0.06, respectively. The maternal heritability (h2m) of these traits were 0.32±0.09, 0.33±0.10 and 0.33±0.09, respectively. The direct-maternal correlations (rdm) were strong and negative. The medium heritability estimates for direct effects suggest that progeny tests should be used in this population to increase genetic improvement.
SummaryAn automatic aeration controller was constructed to assure the optimal amount of oxygen for aerobic biosynthetic processes. A platinum electrode and a KCl bridge for the calomel electrode were inserted hermetically into the fermentor and were sterilized with the culture medium. The electrode potential developed a t the surface of the Pt electrode continuously indirated the actual oxygen concentration of the medium. This served as the controlled variable of the system. The concentration of dissolved oxygen resulted from the actual demand and supply of the microorganism. The electrode potential, which was the measured variable of the process, operat.ed a closed-loop automatic aeration system. The controller activated an air inlet valve in order to balance t,he cont,rolled variahle. The automatic controller operated in fermentors of industrial scale for long periods in a satisfactory manner.
SummaryThe oxygen demand of Penicillium chrysogaum culture was supplied by an automatic aeration control system on the basis of the actual respiration of the cells. The simultaneous use of the automatic aeration apparatus and a turbomixer of great shear stress revealed that some effects of agitation are independent of aeration. These effects of agitation are manifested in two ways: (1) in the increased break down of the cell clumps, thus assuring large free cell surfaces for contact with the substrates; and (Z?) in the increased mixing effect, which assures a continuous mass transfer towardes the free cell surfaces. These effects of the agitation can improve the yield when the 0 2 level is maintained near to the saturation value.
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