Tensile characterization and life cycle assessment of fungal-colonized 3D-printed PLA/wood biocomposites.

This study investigates the mechanical behaviour of additively manufactured biocomposites based on PolyLactic Acid (PLA) reinforced with nominal wood-particle contents ranging from 10 to 50wt. % and subsequently subjected to controlled growth of the fungus Fomes fomentarius. The aim was to analyse how post-printing fungal colonisation and the associated processing conditions influence the mechanical characteristics of the resulting wood-containing PLA specimens, particularly Young's modulus (E), mean Ultimate Tensile Strength (UTS), and overall deformation behaviour. Standardised tensile tests were performed, and the corresponding stress-strain curves were evaluated. The investigated PLA/wood material combinations exhibited noticeable differences in tensile behaviour, with mean Young's modulus (E) values ranging from 2231 to 2685 [Formula: see text] and mean UTS values ranging from 31 to 38 [Formula: see text]. Specimens subjected to fungal colonisation and the associated incubation, drying, and handling procedure consistently exhibited lower mean E and mean UTS values than the corresponding untreated specimens . Mean Young's modulus decreased by approximately 7-11 %, while UTS decreased by approximately 2-7 %, depending on the material combination. Microscopic observations confirmed successful surface colonisation by Fomes fomentarius, whereas fungal growth within the internal specimen structure could not be detected. In addition, a supplementary screening-level Life Cycle Assessment (LCA) was conducted to compare the environmental impacts associated with the investigated PLA/wood material combinations during the Material Extrusion Additive Manufacturing (MEX AM) fabrication stage. The results indicate that electricity consumption dominated the Global Warming Potential (GWP), whereas material composition had a stronger influence on Acidification Potential (AP) and Eutrophication Potential (EP). The combined mechanical and screening-level environmental assessment provides indicative insights into the trade-offs associated with bio-based PLA/wood material combinations and their post-printing biological modification, supporting future work on more sustainable additively manufactured material systems.