Grantee Research Project Results
Final Report: Growth and Fungal Resin Generation for Manufacturing Novel, Formaldehyde-Free Wood Particleboard
EPA Contract Number: EPD17043Title: Growth and Fungal Resin Generation for Manufacturing Novel, Formaldehyde-Free Wood Particleboard
Investigators: Meeks, Daniel
Small Business: Ecovative Design, LLC
EPA Contact: Richards, April
Phase: I
Project Period: September 1, 2017 through February 28, 2018
Project Amount: $99,995
RFA: Small Business Innovation Research (SBIR) - Phase I (2017) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Green Buildings
Description:
Engineered wood products are ubiquitous in structural (construction: oriented strand board, plywood) and non- structural applications (furniture: medium density fiberboard, particleboard), and are traditionally comprised of wood particles or fibers, waxes, and resins. Although engineered wood represents a $8.5B market in the United States annually, the rising costs of resins and the detrimental human health concerns associated with these adhesives has led to many of the products being manufactured overseas. The most common resins are urea formaldehyde (UF) or methylene diphenyl diisocyanate (MDI), which emit toxic volatiles either post or during production respectively. Increase in resin costs and the decline in US building and construction beginning in 2008 led to 16 of the American non-structural engineered wood mills to close. With the rebound of the housing market (5.6% annual growth), domestic companies are struggling to meet rising demand and most are operating at less than 75% capacity. The US is currently a net importer of engineered wood, which is predominately seen in the $1.09B deficit of non-structural boards used in furniture and cabinet applications. Imported materials from Southeast Asia, however, have occasionally failed to meet regulatory requirements for formaldehyde emissions, which has led to recalls over human health concerns4 and detrimental impacts on some American businesses (Lumber Liquidators). Regulations driven by state (Air Recourse Board, CA), federal (EPA RIN 2070- AJ44), and international (European Commission on the Environment) governments are starting to phase out the aforementioned toxic resins and a natural alternative that can meet the performance and cost metrics is required to fill the void.
LD boards are defined by the American National Standards Institute (ANSI) as a nonstructural board that has a density that is less than 40 lbs/ft3, with most between a 30 -35 lbs/ft3 density. These boards are predominately found in door core, counter top, and furniture core applications. Ecovative’s commercial insulation board, which is grown at a 7 lbs/ft3, would go anoxic and cease growth at such an elevated density, and these denser products are enabled by the aerated bed reactor that will be further refined under this scope of work. Through active aeration that mediates gas exchange and heat transfer, fungal bound wood particles can be grown to approach the density and performance of low density particleboard, and long press cycles are avoided. LD board’s smaller market segment is ideal for fostering iterative processing scale-up, and has several characteristics which make them ideal as a primary entry market space. Existing LD boards have a higher press factor and require more urea-formaldehyde resin than higher density boards due to limited particle to particle interaction, making them more expensive to produce per square foot than higher density boards. Conversely, Ecovative estimates that production of LD boards will be 60% less expensive than production of M2 boards excluding capital expenditures. Additionally, higher resin loading in conventional LD boards allows Ecovative to displace more urea formaldehyde (UF) resin per square foot produced. Ecovative’s mushroom technology is well suited to many applications within this market segment, specifically adding value to products such as fire door cores due to mycelium’s innate heat and flame resistance. LD board mechanical performance metrics are also more easily reached, and can potentially be achieved with Ecovative’s technology at a lower density than with conventional offerings. Early advances in the LD core market, between the time the proposal was submitted and the program began, have attracted a number of potential early customers, which include door and furniture manufacturers.
Summary/Accomplishments (Outputs/Outcomes):
Over the course of the six-month work plan the Ecovative Research and Development team developed, refined, and
reproduced a novel solid-state fermentation system that was coined an “Aerated Bed Reactor” (ABR). The ABR is composed of a large rectangular bin, currently 4’ x 4’ x 3’, that is outfitted with an air plenum at its base. This was scaled from the preliminary research, which was conducted with an 8” diameter tube reactor. The bins were filled with an aspen wood chip (NEPCO, Warrensburg, NY) that were hydrated (65% moisture content on a dry mass basis), pasteurized, and inoculated with a strain of filamentous fungus. Once filled, the ABRs were connected to a custom designed air handling and conditioning system. The conditioning system serves two principle purposes: (1) to humidify and cool in the incoming air the reduce the heat load generated by the fungal metabolism; and (2) to replace any accumulated carbon dioxide (CO2) with ambient oxygen (O2), which enables homogenous mycelium growth through the depth of the wood chip substrate.
The mycelium culture is incubated within the ABR for an initial five days, which allows the culture to establish itself on the wood chip substrate and be less susceptible to contamination. On the fifth day, the colonized wood chips are broken up using a trommel, supplemented with a carbohydrate, and reapplied to the ABR. Another four-day incubation period then commences in which the mycelium rapidly proliferates and provides the strongest network of filamentous fungal tissue. During the course of the work plan the team optimized the incubation time and intervals, garnered a greater understanding of temperature profiles that provide for the best tissue growth for strength, and began to refine the plenum system to deliver the most ideal conditioned air. The ABR technology was founded on the in-vessel aerated composting infrastructure, which will allow this platform to match throughput of a conventional particleboard mill (650 tons/day). The team used the constraints from this composting infrastructure to design a system that can meet the economic demands of the industry without a tremendous capital expense requirement for new construction.
Once the nine-day incubation cycle was completed the billet of mycelium colonized and bound wood chips is ejected from the ABR bin simply by tipping it over with a fork truck. The resultant cubes were then cut on a horizontal saw mill, common in forestry, and dried using a forced convection oven. The panels cut to sizes ranging from 0.5” to 4” in total thickness, and then sanded using a wide belt sander to a thickness tolerance of 0.01”. These mCore™ panels were shipped to perspective customers in the furniture, door, acoustic interiors, rigid board insulation, and marine restoration industries.
Conclusions:
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Low density, mycelium bound mCore™ panels offered internal bond strength that is superior to conventional low-density particleboard (LD-1). The wood chip size and geometry were found to be imperative to achieving consistent cohesive growth, and other wood species in the same chip format will be qualified.
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The temperature of the growing culture has a meaningful impact on final mCore™ panel performance, with a temperature of 80ºF currently hypothesized to be the optima for tissue strength. Plenum design iterations have significantly improved the consistency of the airflow throughout the reactor by homogenizing the conditioned air that is blown through the pile. A significant backpressure is created by the mycelium during the second phase of growth, which has been correlated to performance.
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The mCore™ panels can fit into existing post-processing equipment used in the engineered wood industry, including sanding, cutting with a saw mill, and computer numerical controlled routing.
SBIR Phase II:
Parameter Development for the Scaled Manufacturing of Mycelium Bound Panels for Commercial Interior Products | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.