Morphological growth pattern of Phanerochaete chrysosporium cultivated on different Miscanthus x giganteus biomass fractions

Abstract

The growth pattern of Phanerochaete chrysosporium on different Miscanthus x giganteus biomass fractions was investigated via an original method based on microscopy and image processing. The growth medium, together with image acquisition, was designed to study the mycelia growth non-invasively. Object coalescence, the colonized surface area, and radial expansion of the colony were measured. The substrate was sterilized by autoclaving, which could be considered a pre-treatment. The fastest growth rate was measured on the entire biomass, followed by the soluble fraction of the biomass, and finally, the residual solid fraction of the substrate pre-treated by autoclave. The growth rate on the different fractions of the substrate was additive, suggesting that both the solid and liquid fractions were used by the fungus, although the solid fraction of the substrate seemed to provide a richer but less accessible nutritional source. Based on the FTIR analysis, there were differences in composition between the solid and soluble fractions of the substrate, but the main components for growth were always present. We propose using this novel method for measuring initial fungal growth by following the variation of the number of objects over time. The methodology may be applied to the examination of other filamentous fungi.