Quantification of mycelial architecture and growth of wood-decay fungi in microfluidic devices and its relevance for mycelial bio-composites

Abstract

The mycelium enables a fungus to explore and interact with spatially and temporally heterogenous environments. It operates at a range of scales, with hyphal traits and cellular events affecting network and colony behavior. Recently, the fungal mycelium has also been used to produce new, sustainable biomaterials which can serve as alternatives to numerous non-renewable or polluting materials and products. Understanding the rules that govern the mycelium at the micro- and macroscale and what factors influence this is of importance for both fungal biology and ecology, as well as mycelial biomaterials. However, little is known about the architecture, growth and behavior of the mycelium at the hyphal scale and how these microscale traits may influence physico-mechanical properties of mycelial biomaterials at the macroscale. The aim of this thesis was to quantify the microscale mycelial architecture and growth of wood-decay fungi grown on different carbon sources in microfluidic devices and explore whether microscale traits correlated with growth and physico-mechanical properties of fungal myco-composites (MCs). Inherent differences were found in growth characteristics between species. No distinguishable trait-syndrome was observed at the microscale. Instead, great variability in architecture and growth characteristics was observed between the wood-decay fungi. Moreover, a greater growth variability was demonstrated between species on glucose than carboxymethylcellulose. For the MCs, clear differences in fungal growth and biomass production were found between species. However, it was not possible to directly extrapolate microscale architecture and growth traits from the microfluidic devices to explain growth and physico-mechanical properties of the MCs at a macroscale. This disparity was partially due to limitation in the microfluidic methodology, as well as added environment complexity in MCs. Nonetheless, the ecological niche of the different wood-decay fungi could partially explain the variation in growth on different substrates, in both the microfluidic and MC set up.

Popular Abstract

Unveiling the hidden world of Fungi

Most people know fungi for the characteristic mushrooms they buy in the supermarket or encounter in the forest. However, the largest part of their lifeform and exhibited behavior is found below ground, concealed to the human eye. The body of a fungus is made up of a network of microscopic cells called hyphae, that grow into a root-like structure known as the mycelium. Advances in both growth and microscopy methods and the innovation of fungal biomaterials have allowed for innovative research on their lifeform and growth, both on the micro- and macroscale.

The mycelium is one of the defining features of the fungal lifestyle. It allows a fungus to explore the environment and change its appearance by splitting, fusing and recycling its hyphae based on cues such as nutrients and predators. Moreover, it spans and interacts with its environment over a range of scales, from individual hyphae at the micrometer scale to whole organisms that are spread over hectares of forest floor. More recently, the mycelium has also been key in producing sustainable biomaterials which can serve as alternatives to products such as leather or packaging. The aim of this thesis was to explore the microscale growth of seven different fungi and to explore whether microscale growth traits correlated with material properties of mycelium-based biomaterials.

Fungal growth was followed under the microscope in micro-chips. These chips are designed to answer fundamental questions about the behavior and growth of individual hyphae. The mycelium-based biomaterials were produced by growing the fungi into wood shavings, where the mycelium acted as a glue to keep them together.

There was a great variability in fungal growth between species under the microscope, with differences in the density and length of the mycelium and their ability to recycle themselves. For the biomaterials, clear differences in fungal growth were found when growing the different species on the wood shavings. This resulted in varying degrees of mycelium covering the wood and impacted the fragility of the materials when they were handled. Fungal growth at the microscale was not able to directly explain and predict the differences in the mycelium-based biomaterials. For example, a large amount of area covered by the mycelium under the microscope did not correctly predict a dense growth and ability to bind the wood shavings together. This difference was partially due to limitations in the methodology, as well as the biomaterials being a more complex environment.

Even though there was no direct correlation between the microscale growth found under the microscope and in the biomaterials, the ecological niche and evolutionary relationship of the fungi was able to partially explain the growth variation between species in both experiments. However, there is more to be done to understand the influence of fungi on the performance of biomaterials, such as the composition of the hyphae or production of compounds that may facilitate adherence.

Master’s Degree Project in Molecular Biology, 45 credits MOBN02
Department of Biology, Lund University

Advisors: Dimitrios Floudas & Kristin Aleklett Kadish
Department of Biology, Lund University

• author: van Bokhoven, Roos-Marie
• supervisor: Dimitrios Floudas; Kristin Aleklett
• organization: Degree Projects in Molecular Biology
• course: MOBN02 20232
• year: 2024
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• language: English
• id: 9176416
• date added to LUP: 2024-10-10 15:28:29
• date last changed: 2024-10-10 15:28:29