Filamentous fungi are used prevalently in the bioprocess industry to produce a host of products representing billions of dollars in annual sales.  In many, or perhaps even most of these processes, fungi are starved for carbon.  This occurs both by design (e.g., in fed-batch processes) and by default (e.g., from inadequate mixing due to high broth viscosity).  We have hypothesized that nutrient limitation leads to changes in the material properties of fungal mycelia which subsequently leads to changes in susceptibility to fragmentation.  To study these phenomena, Aspergillus nidulans is used as a model organism.  An atomic force microscope (AFM) is used to test mechanical properties of the fungal cell wall as a function of axial position.  In addition, high shear mixing and digital imaging are used to assess susceptibility of mycelia to fragmentation, and to make deductions regarding the tensile strength of fungal cultures.  Results from these studies will be presented.