Applicability of Penicillium chrysogenum rheological correlations to broths of other fungal strains

Existing correlations of Power law consistency index with Penicillium chrysogenum biomass concentration and morphology were revised using a microscope magnification of 50 times to characterize the latter, rather than the 80 times used previously. This allowed tests of the correlations on broths of Aspergillus oryzae and Aspergillus niger, which have such large mycelial sizes that a lower magnification is required for accurate morphological analysis. The new correlations were successful at predicting the rheology of A. oryzae broths but not A. niger broths, which may be because of a change in the exponent on the biomass concentration in the correlations for the latter. Because the mean maximum dimension of clumps is magnification independent, the preferred correlation was: K = C-m(2) x [4 x 10(-5)D - 9 x 10(-4)] where K is the consistency index (Pa s (n) ), C (m) is the biomass concentration as dry cell weight (g l(-1)) and D is the mean maximum dimension (mu m).