Mycelium materials hold the potential to react to their environment if kept in a dormant or alive state, representing a promising avenue in the ELM landscape. Light is not just a critical parameter for the induction of native processes (e.g., asexual spore formation, tissue differentiation, pigment biosynthesis), but also an engineerable abiotic factor that can bring control to the embedded physiological responses of the fungus.

The effect of different light wavelengths on the mycelium formation of Trametes versicolor was explored under continuous illumination in liquid static fermentation. Preliminary results showed that biomass formation was correlated with culture pH at harvest. UV wavelength (365 nm) exhibited a dual effect, either promoting or inhibiting growth depending on intensity, and revealed a high potential for photomasked designs. Blue light (465 nm) induced the initiation of sexual development and green light (536 nm) was highly variable. Pigmented exudates were sometimes observed under red light (660 nm) stimulation and far-red (730 nm) conditions exhibited a similar phenotype to those observed in dark conditions.

The obtained results on appearance, biomass, heterogeneity and pH will be combined with other phenotypical assessments, including asexual spore formation and mechanical properties of the resulting material. This information will be complemented with light cycling and growth directionality assays. The present line of research provides a comprehensive framework to induce programable responses during the material's lifespan by leveraging the photophysiology of the organism.