Biochemical Engineering Aspects of Solid State Bioprocessing
83
Fig. 4. a The concentration gradients which arise within substrate particles, shown for the
growth of an amylolytic unicellular organism on a substrate containing starch. b The consequences that clearing of starch at the particle surface has on the rate of glucose generation
within the substrate particle by the glucoamylase
located in different regions of the particle will be experiencing different
nutrient concentrations. Likewise, there are oxygen concentration gradients
within the substrate and cells or hyphal tips located in different regions of the
particle will be experiencing different oxygen concentrations [86].
It is logical to express the specific growth rate of a cell or a hyphal tip at a
particular location in the same manner that is common in SLF, namely by use