A fractal model for the characterization of mycelial morphology

Abstract

A new technique based on a fractal model has been developed for the quantification of the macroscopic morophology of mycelia. The morphological structuring is treated as a fractal object, and the fractal dimension, determined by an ultrasonic scattering procedure developed for the purpose, serves as a quantitative morphological index. Experimental observations reported earlier and simulations of mycelial growth, carried out using a probabilistic-geometric growth model developed for the purpose, both validate the applicability of the fractal model. In experiments with three different species, the fractal dimensions of pelletous structures were found to be in the range 1.45-2.0 and those of filamentous structures were in the range 1.9-2.7, with values around 2.0 representing mixed morphologies. Fractal dimensions calculated from simulated mycelia are in rough agreement with these ranges. The fractal dimension is also found to be relatively insensitive to the biomass concentration, as seen by dilution of the original broths. The relation between morphology and filtration properties of the broths has also been studied. The fractal dimension shows a strong correlation with the index of cake compressibility and with the Kozeny constant, two filtration parameters that are known to be morphology dependent. This technique could thus be used to develop correlations between the morphology, represented by the fractal dimension, and important morphology-dependent process variables.

Simulation of growth of a filamentous fungus in 3 dimensions

“…Obert and co-workers (1990) found a very similar evolution, based the analysis of the growth in 2 dimensions of Streptomyces griseus and Ashbya gossypii. Patankar et al (1993) found a fractal dimension of simulated pelletous growth of 2.28 when the width of the growth zone was large (not specified).…”

“…However, this transition can be explained by the fact that the dense network of hyphae in the center of mature colonies results in a black blob upon binarization, thus effectively hiding the structure of the underlying hyphae. Patankar et al (1993) developed a simple tridimensional growth simulation scheme. The main purpose of the model was to generate data for the subsequent fractal analysis of the growth pattern.…”

A review of factors affecting filter cake properties in dead-end microfiltration of microbial suspensions

“…In related studies, Patankar et al [26] examined the relation between the 'mean' morphology of filamentous suspensions and their filtration characteristics. Morphology was quantified as a fractal dimension and the fractal dimensions of pelleted structures were found to be in the range 1.45-2.0, while those of a filamentous nature were in the range 1.9-2.7, with values around 2.0 representing mixed morphologies.…”

Morphological Instabilities in a Growing Yeast Colony: Experiment and Theory

“…Turing patterns have found application in a variety of biological systems [2,3]. Lately the interplay between form and formation in biological morphologies have been investigated by physical modelling in swarms of swimming bacteria [4,5], in growth of bacteria colonies [6][7][8][9][10][11], and in growth of various fungi [12][13][14].…”