Chapter 3 where AX is amount of biomass produced Yx/s is the yield coefficient Whereas the amount of substrate assimilated per unit of biomass formed (AX/ASassimilation)is constant regardless of the growth rate, the overall yield coefficient pendence (Yx/d is variable and dependent upon the environmental conditions within the culture To illustrate this growth rate dependence, consider two extremes: a culture growing at ts maximum specific growth rate will use most of its substrate for assimilation and rowth energy, whereas a stationary phase culture(non growing) will consume substrate for maintenance without any growth From the biotechnological process point of view, yield coefficient variability is extremely important and yield coefficients must, of course, be optimised Later in this chapter(section 3. 2. 1) we shall consider yield coefficients with respect to 3.1.2 Elemental material balances for growth The stoichiometry of growth and metabolism can also be described by elemental material balances. This approach can provide an insight into the potential of the organism for biomass or product production, and thus the scope for process An elemental material balance approach to growth stoichiometry requires an empirical formula for dry weight material The ratios of subscripts in the formula can be determined if the elemental composition of an organism growing under particular conditions is known. a unique cell formula can then be established by relating elemental composition to one gram-atom of carbon ieθ=1,thenα,阝,andδ are set so that the formula is consistent with known relative elemental weight content of the cells. The formula can be extended to include other elements to be a significant proportion of cell matel lemental analysis shows these macro-elements, such as phosphate and sulphur, if Complete the following statements 1)One C-mol of cells is the quantity of containing one gram-atom of 2)One C-mol of cells corresponds to the cell weight with the carbon subscript (e)taken as The missing words are: 1)cells and carbon 2)'dry' 'unity Use the data on elemental composition shown below to determine the empirical chemical form nd the formula weight for the yeast38 Chapter 3 where AX is amount of biomass produced Yx/s is the yield coefficient Whereas the amount of substrate assimilated per unit of biomass formed (AX/GaSMrmkt,,,,,) is constant regardless of the growth rate, the overall yield coefficient (Y,,J is variable and dependent upon the environmental conditions within the culture. To illustrate this growth rate dependence, consider two extremes: a culture growing at its maximum specific growth rate will use most of its substrate for assimilation and growth energy, whereas a stationary phase culture (non growing) will consume substrate for maintenance without any growth. From the biotechnological process point of view, yield coefficient variability is extremely important and yield coefficients must, of course, be optimised. Later in this chapter (section 3.2.1) we shall consider yield coefficients with respect to product formation. 3.1 -2 Elemental material balances for growth The stoichiometry of growth and metabolism can also be described by elemental material balances. This approach can provide an insight into the potential of the organism for biomass or product production, and thus the scope for process improvement. An elemental material balance approach to growth stoichiometry requires an empirical formula for dry weight material: Ce Ha Op Ns growth rate dependence empirid fOm~Ia for dV biomass The ratios of subscripts in the formula can be determined if the elemental composition of an organism growing under particular conditions is known. A unique cell formula can then be established by relating elemental composition to one gram-atom of carbon, ie 8 = 1, then a, p, and 6 are set so that the formula is consistent with known relative elemental weight content of the cells. The formula can be extended to include other macro-elements, such as phosphate and sulphur, if elemental analysis shows these elements to be a significant proportion of cell material. n Complete the following statements: 1) One C-mol of cells is the quantity of containing one gram-atom of 2) One C-mol of cells corresponds to the cell weight with the carbon subscript (e) taken as The missing words are: 1) 'cells' and 'carbon'; 2) 'dry' and 'unity'. Use the data on elemental composition shown below to determine the empirical n chemical formula and the formula weight for the yeast