Ultrasonic characterization of mycelial morphology as a fractal structure

Preliminary measurements of scattering of ultrasound from filamentous microorganisms in aqueous-medium suspensions are reported. The data are used to characterize the structuring (morphology) between the organisms quantitatively by modelling the morphology in terms of fractal structures and obtaining the fractal dimension as the characteristic parameter. The fractal dimension is calculated from the slope of a log-log plot of scattered intensity versus the scattering vector magnitude. The intensity is measured over a range of magnitudes of the scattering vector by varying the scattering angle as well as the ultrasonic frequency. Results from microbial suspensions of different species and different morphologies indicate that the fractal dimension can be used to quantify the morphological state of a suspension. The fractal dimension ranges from around 1.5 for suspensions with pelletous morphology to around 2.5 for suspensions with filamentous morphology.