From Decay to Design: 90 Years of Wood–Fungi Bioengineering Eco-Innovation

This study revisits mykoholz (myco-wood), a mid-20th-century East German innovation that bio-modified solid wood through controlled white-rot fungal decay, positioning it as a precursor to modern mycelium-based composites (MBCs). Based on patents, technical literature in German and English, a state-produced documentary, and a declassified U.S. CIA intelligence report, the fabrication methods and applications of mykoholz are reconstructed. The process reduced hardwood density by 75–90% while enhancing porosity, impregnation capacity, and moldability, all without synthetic additives or high energy input. During the 1950s, the CIA even monitored the technology, underscoring its perceived strategic value. Industrial production ceased by 1965 due to challenges of reproducibility and limited automation, yet the underlying principles anticipated current advances in selective delignification, AI-assisted bio-fabrication, and climate-controlled incubation. A comparison with modern MBCs reveals complementary paradigms: whereas mykoholz reconfigured solid hardwood at the cellular level, contemporary MBCs rely on moldable composites grown from lignocellulosic waste. This diachronic analysis highlights mykoholz as an early example of circular, low-energy bioengineering and suggests that historic fungal modification techniques could inform the development of hybrid, scalable, and eco-compatible material systems.