Enabling community-based metrology for wood-degrading fungi

Abstract

Lignocellulosic biomass could support a greatly-expanded bioeconomy. Current strategies for using biomass typically rely on single-cell organisms and extensive ancillary equipment to produce precursors for downstream manufacturing processes. Alternative forms of bioproduction based on solid-state fermentation and wood-degrading fungi can enable more direct means of manufacture. However, such practices are often ad hoc and not readily reproducible. We sought to develop standard reference strains, substrates, measurements, and methods sufficient to begin to enable reliable reuse of mycological materials and products. Specifically, we show that a widely-available and globallyregularized consumer product (Pringles™) can support the growth of wood-degrading fungi, and that growth on Pringles™ can be correlated with growth on a fully-traceable and compositionally characterized substrate (NIST Reference Material 8492 Eastern Cottonwood Biomass). So established, five laboratories were able to compare measurements of wood-fungus performance via a simple radial extension growth rate assay. Reliable reuse of materials, measures, and methods is necessary to enable distributed bioproduction processes that can be adopted at all scales, from local to industrial. cells, known as hyphae, chitinous-composite cell walls, vast repertoire of degradative enzymes and secondary metabolites, and interconnected networks of cells, known as mycelium, that form through a combination of apical growth, hyphal branching, and regulated self-fusion 22-31 . Growing mycelium penetrate and degrade the substrate upon which the organism lives and uptake and shuttle nutrients throughout complex hyphal networks 23 .Mushrooms, the reproductive structures of wood-degrading filamentous fungi, are widely-used as foodstuffs and as a source of medicines and are consequentially revered by many cultures [30][31][32] .Additionally, mycological materials made from the tissues of mushrooms are used in meat replacements, filtration and remediation of contaminated water, packaging materials, furniture, textiles for the fashion industry, architectural design, art, materials for super capacitors and batteries, anti-viral therapeutics for bees, and nanoparticle synthesis 35,36,45,46,[37][38][39][40][41][42][43][44] . Most commercial mycological materials are fabricated by placing an organism and substrate mixture into a preformed mold and allowing the mycelium to process the substrate via solid-state fermentation. The process itself is typically halted via thermal inactivation followed by downstream processing.Recent studies have elucidated the impacts that choice of organism, genetic modification, substrate composition, and environmental conditions have on the macroscopic properties of mycelium-based materials [47][48][49][50][51][52][53][54] . Most organisms now used to produce mycelium materials are of the class Agaricomycete in the division Basidiomycota. The Agaricomycete are less-extensively studied and developed as some of their Ascomycota counterparts, such as ...