Mycelium-based composites (MBCs) are highly valued for their ability to transform low-value organic materials into sustainable building materials, offering significant potential for decarbonizing the construction sector. The properties of MBCs are influenced by factors such as the mycelium species, substrate materials, fabrication growth parameters, and post-processing. Traditional fabrication methods involve combining grain spawn with loose substrates in a mold to achieve specific single functional properties, such as strength, acoustic absorption, or thermal insulation. However, recent advancements have focused on digital biofabrication to optimize MBC properties and expand their application scope. Despite these developments, existing research predominantly explores the use of grain spawn inoculation, with little focus on liquid spawn. Liquid spawn, however, holds significant potential, particularly in digital biofabrication, due to its ease of deposition and greater precision compared with grains. This paper, part of a digital biofabrication framework, investigates the growth kinetics of Ganoderma lucidum and Pleurotus ostreatus on hemp non-woven mats, offering flexibility and mold-free fabrication using liquid inoculation. By integrating mycelium growth kinetics into digital biofabricated materials, researchers can develop more sustainable, efficient, and specialized solutions using fewer resources, enhancing the adaptability and functionality of MBCs. The experiment involved pre-cultivating P. ostreatus and G. lucidum in yeast peptone dextrose (YPD) and complete yeast media (CYM) under static (ST) and shaking (SH) conditions. Four dilutions (1:10, 1:2, 1:1, and 2:1) were prepared and analyzed through imagery to assess growth kinetics. Results showed that lower dilutions promoted faster growth with full coverage, while higher dilutions offered slower growth with partial coverage. SH conditions resulted in slightly higher coverage and faster growth. To optimize the control of material properties within the digital biofabrication system, it is recommended to use CYM ST for P. ostreatus and YPD SH for G. lucidum, as their growth curves show clear separation between dilutions, reflecting distinct growth efficiencies and speeds that can be selected for desired outcomes.

This study investigates the growth behavior of G. lucidum and P. ostreatus liquid spawn on non-woven hemp mats. A Complete Yeast Medium (CYM) and Yeast Peptone Dextrose (YPD) medium were used under static (ST) and shaking (SH) conditions to develop four precultures per species. Mycelium was cultured from agar plates into liquid media and incubated at 27 °C for 5 days. Non-woven hemp mats were sterilized and inoculated with 4 dilutions of each precultures. Each mat received 3 mL of liquid spawn, with biological and technical triplicates. Inoculated mats were incubated at 27 °C for 14 days and then dried at 60 °C. Daily photographs tracked growth. Using ImageJ, the surface colonization rate was quantified by calculating the mycelium-covered area as a percentage of the mat. This enabled comparison of media, fungal species, and dilution effects on growth kinetics

Mycelium-based composites (MBC) are valued for their ability to convert low-value organic materials into sustainable building resources, making them a promising solution for decarbonizing the construction sector [1-5]. MBC performance is influencing by various factors including mycelium species, substrate composition, growth conditions, and post-processing techniques [1,6]. Conventional fabrication methods involve combining grain spawn with loose organic material to achieve specific functional properties, such as strength, acoustic absorption, or thermal insulation [7,8]. Recent advancements have increasingly focused on digital biofabrication methods to enhance growth, improve material properties, and shape mycelium materials with a primary focus on additive manufacturing (AM) [9-14]. This approach integrates lignocellulosic substrates with fungal inoculation to create complex composite structures. Most experiments use an extrudable paste to construct scaffolds, with studies investigating the effects of inoculating the paste either before or after fabrication [15-20]. Liquid spawn, however, holds significant potential, particularly in AM, due to its ease of deposition and greater precision compared to grain spawn. Combining liquid spawn and AM has the potential to control localized growth within MBC, enabling more precise material customization. I propose a new digital biofabrication framework that consists of three key components: (1) computational design, which analyzes material functionalities and generates robotic actions; (2) robotic fabrication, which executes inoculation and time-dependent actions; and (3) biological material selection, encompassing mycelium species and substrate composition.

Mycelium-based composites (MBC) are valued for converting low-value organic materials into high-performance building materials, offering significant potential for decarbonizing the construction sector. MBC properties are influenced by mycelium species, substrate materials, and fabrication growth parameters. In traditional applications, grain spawn is combined with loose particle substrates to achieve specific functional properties, such as strength, acoustic absorption, or thermal insulation, tailored to a single purpose. However, recent advancements have shifted toward creating graded materials—materials in which properties vary gradually throughout the structure. This approach allows for multiple local optimized properties to be incorporated within a single material. As a result, graded materials can support applications that require complex, multifunctional performance, making them ideal for fields like construction where multiple properties are often needed within a single component. This study, part of a digital biofabrication framework, explores controlling mycelium growth via liquid spawn. While liquid spawn has improved mechanical properties, its effects on growth performance have not been fully studied. Non-woven mats, offering flexibility and mold-free fabrication, are proposed as substrates. This paper investigates the growth kinetics of Ganoderma lucidum and Pleurotus ostreatus on hemp non-woven mats using liquid inoculation, comparing it to traditional grain spawn inoculation. By integrating graded properties into digital biofabricated materials, researchers can develop more sustainable, efficient, and specialized solutions using fewer resources, enhancing the adaptability and functionality of MBC.The experiment involved pre-cultivating P. ostreatus and G. lucidum in yeast peptone dextrose (YPD) and complete yeast (CYM) media under static (ST) and shaking (SH) conditions. Four mycelium dilutions (1:10, 1:2, 1:1, and 2:1) were prepared and analyzed through imagery to assess growth kinetics, aesthetics, and potential material properties. Results showed that lower dilutions promoted faster growth with full coverage, while higher dilutions offered slower growth with partial coverage, providing more control during incubation. Shaking conditions resulted in slightly higher coverage and faster growth. CYM medium resulted in G. lucidum and P. ostreatus closely matching the grain spawn growth curve across all dilutions, compared to YPD medium. To optimize the control of material properties within the digital biofabrication system, it is recommended to use CYM ST for P. ostreatus and YPD SH for G. lucidum, as their growth curves show clear separation between dilutions, reflecting distinct growth efficiencies and speeds that can be selected for desired outcomes. P. ostreatus should be preferred for acoustic absorption qualities due to its thin, fibrous growth, while G. lucidum is ideal for strength and aesthetic properties, thanks to its dense growth and color-changing characteristics.

Mycelium-based composites are part of an emerging group of biofabricated materials with potential for sustainable construction and interior applications. Their properties depend on fungal species, substrate composition, incubation conditions, and post-processing strategies, yet the relative influence and controllability of these parameters remain fragmented across the literature. This review systematically analyses 46 peer-reviewed studies to evaluate how externally controllable fabrication parameters affect mechanical, thermal, acoustic, and hygroscopic performance. The biofabrication workflow is structured into pre-processing, incubation, and post-processing stages, with particular emphasis on incubation as an underexplored design domain. While species and substrate strongly determine baseline performance, environmental and physical parameters applied during growth, such as moisture, temperature, aeration, and mechanical confinement, suggest potential opportunities for dynamic property tuning. By proposing incubation as an emerging opportunity for material programming, this review outlines pathways toward digitally controlled, functionally graded mycelium composites, contributing a structured framework for integrating biological growth into biodesign workflows.