Processing yield coefficients

The growth yield coefficients can be calculated [56,58] by sub-dividing metabolism responsible for the whole process of growth and multiplication into ... 

Assuming the P/O-quotient of NADH is 2 and NADPH can be used bioenerge-tically, about 0.5 acetate must be oxidized to neutralize the synthesis. This expenditure of substrate diminishes the product yield coefficient from 0.72 g poly(3HB) per g acetic acid (Table 3) to about 0.57 g per g. Since the experimentally obtained yield coefficient is lower (being, on average, about 0.33 g per g, Table 3), we may draw three conclusions. Firstly, the P/O-quotient is lower than 2. Secondly, the fate of acetate is not strictly determined, i. e., its utilization is not a one-way path and does not terminate in a dead end. Third, there is no doubt that some energy generated from acetate is necessary for homeostasis and turnover processes (maintenance) under conditions of poly(3HB) synthesis and accumulation (with acetic acid as an uncoupler). 

Parametric uncertainty A great number of bacterial species carry out the transformations of organic load and nutrients in wastewater treatment processes without direct or easily comprehensible relationships between the microbial populations and viability. The role of each bacterial species is fuzzy [30], and aspects such as cellular physiology and its modeling are not easily understood from external measurements [18], [68]. As a first consequence, the kinetics of these transformations is often poorly or inadequately known [66]. Extensive efforts to model the kinetics have been undertaken, but these have not been successful to elucidate how yield coefficients, kinetic parameters and the bacterial population distribution change as a function of both, the influent composition and the operating conditions. 

Asymptotic server Ob- Process model, (process kinetics as well as yield coefficients can be estimated on-line), process inputs. It takes specifically into account the nonlinear structure of the system Simplicity of the method Stability and convergence are guaranteed if the inputs are persistent and bounded. Partial model knowledge Inputs knowledge Non-adjustable convergence rate. [6]... 

Asymptotic well as yield coefficients can be es-Observer timated on-line), process inputs. 

Estimate the food-microorganism ratio (F/M) and sludge age (solid retention time) of an activated sludge process designed to reduce the BOD5 of the spent stream generated from a biological production plant from 1500 mg/L to 50 mg/L. The wastewater flow is Q = 15,000 GPD, aeration tank volume = 45 m, MLVSS = 3000 mg/L, and net biomass yield coefficient (Tn) = 0.28 kg/kg. Also compute the performance efficiency of the plant. 

Microbial products may be formed as a result of a variety of processes which occur within the cells of a microbial culture. In some cases the cell itself may be the desired product, or it may be that the product is formed as the direct consequence of its growth. There is in the latter circumstances a direct link between growth and the accumulation of product. However, there are many important microbial products which are not growth-associated, where there may exist mechanisms within the cells, as outlined in Section S.S.2, which operate to produce a particular material only under certain special circumstances. As a result, the yield coefficient Yr,s is of little value in predicting the course of product accumulation, except when the overall productivity of a complete batch operation is considered. 

In the present paper the process monitoring of cephalosporin C (CPC) formation by Acremonium chrysogenum in laboratory investigations are considered. The goal of these investigations was the identification of bottlenecks in the biosynthesis and the improvement of process performance by maximizing the product concentration and yield coefficient and by minimizing the byproducts, which impair the product purification. 

Ai 2 / AS V 2 where the inequality between the numerical and physical wavenumber has been enforced. The prior expressions can be viewed as polynomials of the unknown coefficients whose values minimize (2.110). Focusing on and bearing in mind the condition R2 > 0, one deduces that the solution of 3vj/BR= 0 provides a value of R that minimizes the temporal error. More specifically, this process yields... 

It should be obvious that the production of MV portfolios is not extraordinarily input intensive. Efficient frontiers for five asset portfolios require only five predicted returns, five standard deviations, and a five-by-five symmetrical matrix of correlation coefficients. Yet the process yields indispensable information that allows investors to select suitable portfolios. 

An alternative approach to consideration of the multiple routes by which the limiting substrate is consumed in a bioreactor is to reexamine the pathways shown in Figure 13.3 and to write an expression for the rate of consumption of the limiting substrate when it proceeds via a particular pathway. The total rate at which substrate is consumed can then be written as the sum of the rates of consumption via the individual pathways. Thus, in terms of our formulation of the convention for yield coefficients for metabolism of cells that takes place in a constant-volume closed system, the rate of consumption of substrate can be expressed as a sum of terms associated with the rates at which biomass and other products of metabolic processes are formed plus a maintenance coefficient, m, that characterizes the rate at which a cell in a resting state must consume substrate for maintenance activities if it is to remain aUve ... 

Studies of the production of an organic acid using Aspergillus niger in continuous cultivation with recirculation of the biomass indicate that under the conditions employed = 0.835 h and = 0.10 g/L. The yield coefficient T /s i . 01 g dry biomass/g substrate and p/s is 0.48 g/g. Use a spreadsheet to prepare plots of the concentrations of biomass, substrate, and product leaving the CSTBR, as well as the productivity of the process. 

The subscripts on the usual process parameters indicate the positions in the process to which these parameters refer. The kinetics of yeast growth can be described by a Monod rate expression with = 0.625 h and Kg = 2 g/L. Cell death and cell maintenance effects are negligible, as is formation of products other than yeast cells. The yield coefficient x/s is 0.44. The effluent from the bioreactor flows directly to a membrane filtration apparams. The membrane is completely permeable to the substrate, so the concentrations of the substrate in the CSTBR, the effluent from the bioreactor, and the permeate from the membrane and in the recycle stream are all identical. The membrane rejects a substantial proportion of the yeast cells so that the ratio of the concentration of yeast in the recycle stream is a factor of 4 larger than that in the effluent from the CSTBR. Volumetric expansion and contraction effects may be considered negligible. 

As a consequence, materials characterized by a higher yielding coefficient n are good candidate for drawing process. 

A crystallization process has to be designed to meet a number of requirements, for example, particle properties such as particle size and purity. As concerns the purification, a continuously operated crystallization has to deal with the accumulation of impurities in the mother liquor. The drain point for these impurities has to be carefully chosen. It is one of the most underestimated aspect of the process design activity and the source of many errors. Moreover, the process yield is strongly connected with the planning of the process drain points, as is the specific energy consumption and, thus, the success of the process. However, die separation attribute of the unit operation crystallization may not be the best available and one should remain open for competing alternatives. That could be recommendable, for example, in cases of solid solutions, especially with distribution coefficients close to 1, which are not feasible to separate by crystallization at all. 

The increase of fluorescence intensity with time associated to the capture of pyrene by poly(styrene)-poly(meth-acrylic acid) micelles or the capture of perylene by poly(2-cinnamoylethyl methacrylate)-poly(acrylic acid) micelles revealed a two-step process. For the first system, the analysis of the slow process (probe penetration in the micelle core) using the same diffusion equation as for the release process yielded a value of the diffusion coefficient close to that inferred from the release of pyrene by the same micelles. ... 

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