Fundamentals of Fermenter Design

The influences of environmental (macro) conditions and those on the cell level are treated from the point of view of heatand mass-transfer in microbial systems. The effects considered are (i) consumption of substrates, (ii) output of products, (iii) production of heat and (iv) aggregation, as far as concerns direct influence on the microenvironment. The other properties which may have indirect effects on the microenvironment considered are (a) changes in the rheological behaviour of the culture, and (b) changes in interfacial tension. The problem of environmental control is treated for the case of a well-stirred fermenter, and the control factors considered are system geometry, aeration rate, intensity of agitation, temperature, pressure, nutrient supply, pH and other parameters involving specific ions, dilution rate in continuous systems, and foaming.