Mycelium Ex'Spore'ation

Inspiring Designers, Manufacturers, and People in Aotearoa to explore the use of mycelium biomaterials

in order to decrease negative material effects and to reconnect people to nature.

Mission of the project

Hi, my name is Rachel. As a Materials Researcher and Sustainable Design Consultant by trade, I am intrigued, awed, and excited by biomaterials and biofabrication - the act of growing products. In particular mycelium, the root structure of fungus, which can be grown through a substrate to create a solidly binded, water resistant, fire resistant, thermally insulating material. When I started experimenting with the process of growing mycelium, I was drawn towards the challenge of designing out the plastic mold typically used to grow within, and replacing it with a biodegradable one.

Through this site, I share my exploration of the use of natural and sustainable molds in the process of growing mycelium biomaterial. I have also included a video of my at home making / growing process. My hope is that what I have learned will be helpful to others on the same path and will inspire more mycelium biomaterial production in Aotearoa.

Process

In this video you can learn my process for growing mycelium hemp substrate into objects in the comfort of your own home. Notable tips and tricks I have learned through the process can be found below, along with a summary of all the biodegradable mold materials I tested.

Biodegradable Molds

Below is a summary of my findings experimenting with a variety of renewable and biodegradable molds. As mycelium is 'nature's glue,' it tends to bind to any natural material. Therefore, my experimentation followed the concept of the mold becoming a part of the final product.

Coarse Wool

I thought the coarse wool would be too thick for the mycelium to grow through but it wasn't - the mycelium travelled all the way through the thick mold. It gave structure and coating to the wool. The more enclosed spaces within the mold more-so encouraged the mycelium to make its way through the wool, whereas the open spaces encouraged the mycelium to grow towards the open space instead.

Harakeke

Harakeke should be dried to an extent before weaving, preventing the leaves from shrinking and leaving gaps in the mold. The baking process does dehydrate the Harakeke to a point where it is a bit dryer than desired, this requires more testing to mitigate. Very important to clean / boil and sterilise leaves before growing, one of my molds became infected. Was an honour to work with this material given its strength and significance to Aotearoa.

Woven Paper

The woven paper 'fabric' was great to work with because it holds shape very easily and can gave a really sturdy structure to the material. It was also easy to sew and fill.

The mycelium took a while to work its way through this material and it would be good to test a few more days of growth to see if a thicker overcoat is achievable. May be the paper material is quite dense.

Linen

The linen allowed the mycelium to come through fairly easily and evenly, although a few extra days were required during the growing process to achieve this.

This was one of the first tests I did. Afterwards, I realised that by sewing seperate 'pockets' into fabric, I could achieve better shape. Because this was a vase form, I used a kitchen utensil to hold space within the form. This pocketing is shown below.

Hemp Fabric

Out of all the tests I did, the mycelium had the easiest time coating the hemp fabric. The material I used was already a hemp chip substrate from BioFab, so maybe the mycelium was just used to the hemp or maybe the hemp gave the mycelium extra fuel.

The pocketing also work really well to create shape. The result is very soft and flexible, with a thick outer skin.

Bamboo Paper Towel

I experimented with the bamboo fabric that is sold at the Supermarket as reusable paper towels.

The fabric was really soft and easy to work with, the substrate didn't catch on it too much. The mycelium came through the material but it would be worth experimenting with a longer growth period to get a thicker skin. The fabric and mycelium were so similar in colour that it is hard to tell them apart.

Cotton Muslin

The cotton muslin is definitely worth exploring further. Instead of building a form with this one, I wanted to see what would happen if I just grabbed a handful of the mycelium substrate with the fabric and left it in a pile.

The mycelium came easily through the fabric, and bound together the pile of un-sewn fabric. The colour of the fabric paired with the mycelium is lovely in my opinion.

Balsa Wood

I laser cut balsa wood to see how easily the mycelium could come through. The substrate was sandwiched in between two thin pieces of balsa wood and did bind them together, however the bind was not that strong. The mycelium did easily come through the laser cutting and spread itself across the surface of the balsa.

This could be interesting to explore more in some application.

Just Coffee Sack

I would recommend making your own glue out of water and flour to coat the hessian fabric wherever you are planning to cut and sew it, as the weave of a coffee sack is so open that it can fall apart. However, the mycelium loved the material, easily continuing to grow on the fabric far past where the substrate ended. It had a gorgeous finish paired with the mycelium. It also has the huge benefit of being a waste material.

Just Coffee Sack

I learned through the process of making this particular form that a finer substrate or smoother & stronger mold material would be better fit for complex forms. The mycelium grows best when it is packed fairly densely in, and it was difficult to pack this substrate into the feet of the lamp. This was due to the chunky size of the hemp chip substrate and the way the rough jute sack caught on the substrate as it was being stuffed into the form.

Tips and Tricks

There were a few things I learned through this process that will be helpful to anyone experimenting with either growing or growing in biodegradable molds :

-Natural materials need extra sterilisation. I soaked all my molds in 70% isopropyl alcohol for a few minutes and then set to dry in a sterilised box with the lid ajar to allow airflow. This was sufficient for most of my tests. However, the Harakeke basket got infected while growing. In the future, I would recommend boiling molds and then soaking in alcohol and drying, just to be extra careful.

-The air to mycelium substate ratio in your growing box is extremely important. If there is too much air around your molds, they won't grow as well. Try to minimise space within the container by filling with as many molds as possible or putting your molds in a smaller container.

-Raise your molds up off the bottom of the growing box with racks in order to reduce moisture pooling at the bottom of your mold. Be aware the racks will leave a rack pattern on the bottom of your product.

-Try not to open the top of your box too much while your mold is growing, as this disturbs the humidity. But keep your eye out for little brown drops of metabolite. You may want to stop growing and bake / dry if you see one of these, unless you are okay have more brown dots on your finished product.

-Crack the door of your oven just a tiny bit for the first couple hours of baking. This will allow excess moisture from the substrate out of the oven.

-Your growing box does not need to be in the dark. Temperature in the room where your growing box is can vary although temperatures closer to 26 degrees celcius will reduce the time it takes to grow your product. I grew in my living room through winter months into spring. During the winter months, I put insulating material around the outside of my growing back to help it stay warm.

This Project was in Partnership with BioFab

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