7. BioFabricating Materials

Inspiration

This week in the Bioplastics module has been incredible! I've always had a passion for materials, so exploring bioplastics has been fascinating. With my background in Crop Sciences, I see endless possibilities in creating sustainable materials. What excites me most about bioplastics is their environmental compatibility—they break down naturally without contaminating the environment, making them a refreshing alternative to conventional plastics.

Research and ideation

Biofabrication is an innovative field focused on producing sustainable materials by using living cells, organisms, or natural components. It has the potential to replace conventional manufacturing processes, offering alternatives that are biodegradable, renewable, and eco-friendly. Here’s a deep dive into research and ideation around biofabricating materials:

1. Current state of Biofabrication

Biofabrication has grown with advancements in biotechnology, 3D printing, and material sciences. Today, companies and researchers are exploring ways to produce bio-based materials for various applications, including fashion, construction, healthcare, and packaging. Key biofabricated materials already in the market include:

Mycelium-Based Leather:

Mycelium, the vegetative part of a fungus, can be grown to mimic leather. This material is sustainable, biodegradable, and requires less water and fewer chemicals than animal leather. Bacterial Cellulose: Produced by bacteria such as Acetobacter xylinum, bacterial cellulose has applications in wound care, food, and fashion. It’s lightweight, strong, and compostable.

Algae-Derived Plastics:

Algae-based polymers can be used as an alternative to petroleum-based plastics, reducing environmental impact by decomposing more easily.

Silk Proteins:

Produced by genetically engineered bacteria, silk proteins are used in textile manufacturing and biomedical applications due to their strength, flexibility, and biocompatibility.

2. Applications and Market Potential

The biofabrication market spans across various sectors, with significant growth potential in:

Fashion and Textiles:

Biofabricated textiles and leathers are being developed to reduce the carbon footprint of the fashion industry. For example, bio-based leather alternatives provide a cruelty-free and less resource-intensive option.

Healthcare:

Biofabrication enables the production of scaffolds for tissue engineering, which could support regenerative medicine. For instance, bioengineered cartilage or skin could be used in reconstructive surgery.

Packaging:

Sustainable bio-based packaging made from algae or bacterial cellulose can replace traditional plastic packaging, reducing environmental waste.

Construction:

Biofabricated materials like fungal mycelium-based bricks are being tested for building applications due to their insulation properties and sustainability.

3. Emerging Biofabrication techniques

Biofabrication relies on a variety of emerging techniques that combine biology and material science:

Synthetic Biology:

Engineers use synthetic biology to program microorganisms, such as yeast or bacteria, to produce specific proteins or materials. This technique has enabled the production of materials like spider silk without the need for spiders.

Bioprinting:

In biofabrication, 3D bioprinting involves printing with living cells or bio-inks to create structures that mimic natural tissues. This technique is still in early stages for consumer products but has exciting potential.

Fermentation:

Microbial fermentation can be harnessed to grow materials, as seen in Kombucha SCOBY (Symbiotic Culture of Bacteria and Yeast) leather. This material is grown from tea, sugar, and bacterial cultures, and has applications in fashion and packaging.

Mycelium Cultivation:

Mycelium can be cultivated in molds to form specific shapes and textures, and its use in fashion, furniture, and packaging materials is expanding rapidly.

Tree tomato Bioplastic

As part of my exploration into sustainable material development, I chose to create a biodegradable bioplastic using tree tomato (Tamarillo) waste. This project focuses on repurposing agricultural byproducts—such as the skins, pulp, and juice of the tree tomato—to serve as a natural polymer base for bioplastic production. These materials are often discarded, yet they hold great potential for eco-friendly applications.

To produce the bioplastic, I combined the tree tomato waste with gelatin (or agar) for structural support, glycerol as a plasticizer for flexibility, vinegar to improve durability, and water as a solvent. The goal of this assignment is to demonstrate how natural and accessible resources can be transformed into useful biodegradable materials, contributing to the reduction of plastic waste and supporting circular economy practices.

Tools

Tools

Tool	Purpose
Spoons (tablespoon/teaspoon)	For measuring and adding ingredients like glycerol and vinegar
Fork or Whisk	To mix and stir ingredients evenly
Bowl	Medium-sized, heatproof; used to combine all ingredients
Pot or Saucepan	Used for gently heating the mixture on the stovetop
Measuring Cups	For accurately measuring water and other liquids
Blender or Masher	To create smooth tree tomato paste
Flat Plate or Tray	Surface for pouring and setting the bioplastic mixture
Spatula	Used to scrape the bowl and spread the mixture evenly
Non-Stick Surface	Wax paper or parchment paper to prevent sticking on the tray

Safety Tools

To successfully create tree tomato bioplastic, a combination of basic kitchen tools and essential safety items is required. Measuring tools like spoons and cups ensure accurate proportions, while mixing tools such as a whisk or fork help achieve a smooth consistency. Heating equipment like a saucepan is used to gently cook the mixture, and a flat tray with a non-stick surface is essential for shaping and drying the bioplastic. Additionally, safety tools like gloves and heat-resistant mats are important to protect the user from hot surfaces and prevent accidents during the heating and handling process.

Safety Tool	Purpose
Gloves	Protects hands from hot surfaces and sticky substances
Heat-Resistant Mat or Trivet	Provides a safe place to set down hot pots or bowls

Ingredients & Recipes

Ingredient	Amount	Purpose/Action
Tree Tomato (Tamarillo) Waste	100 grams	Natural polymer source; use leftover skins, pulp, or juice
Glycerol (Glycerin)	1–2 tablespoons	Plasticizer for flexibility; adjust amount based on desired flexibility
Gelatin or Agar Powder	10 grams	Provides structure; gelatin is animal-based, agar is plant-based
Water	100 ml	Solvent to dissolve gelatin/agar and mix ingredients
Vinegar (optional)	1 teaspoon	Adjusts pH and helps maintain bioplastic integrity, especially with gelatin

Process and Workflow

Instructions:

1. Prepare the Tamarillo Paste: Blend the tree tomato waste with a bit of water until you get a smooth paste.

2. Dissolve the Gelatin/Agar: In a saucepan, combine water with gelatin or agar powder. Heat gently and stir until it’s fully dissolved.

3. Combine Ingredients: Add the tamarillo paste and glycerol into the dissolved gelatin/agar mixture. Stir well until everything is fully combined.

4. Optional: Add Vinegar: Add vinegar if you're using gelatin to help with the plastic's stability.

5. Heat Mixture: Gently heat the mixture until it thickens, stirring continuously to prevent lumps.

6. Pour and Set: Pour the bioplastic mixture into a mold or spread it out on a flat surface to set. Let it cool and harden for at least 24 hours.

Here’s a step-by-step heating process for making bioplastic from tree tomato waste:

Heating Process

1. Prepare a Double Boiler Setup (Optional but Recommended):

   If possible, use a double boiler to prevent overheating. Place a heatproof bowl over a saucepan of simmering water. This helps control the heat and prevent the mixture from burning.

2. Initial Heating of Water and Gelatin/Agar:

   In a saucepan (or the double boiler), add 100 ml of water and sprinkle in 10 grams of gelatin or agar powder.

   Begin heating the mixture over medium-low heat, stirring continuously to ensure the gelatin/agar dissolves completely and there are no lumps.

   Do not allow the mixture to boil, as boiling can break down the gelatin/agar structure, affecting the bioplastic’s texture. Aim for a temperature between 70-80°C (158-176°F).

3. Add Glycerol and Tamarillo Paste:

   Once the gelatin/agar is fully dissolved, add the 1-2 tablespoons of glycerol and the prepared tamarillo paste.

   Continue to stir the mixture, ensuring that the glycerol and tamarillo paste are evenly incorporated.

4. Heat for a Few Minutes to Thicken:

   Keep the mixture on medium-low heat for another 5-10 minutes, stirring continuously. The mixture should gradually thicken to a syrup-like consistency.

   If you’re using vinegar, add 1 teaspoon at this stage to help stabilize the plastic.

5. Check for Consistency:

   You want the mixture to be thick but still pourable. Avoid letting it boil, as high temperatures can cause the material to degrade.

   If the mixture starts bubbling too much, reduce the heat immediately.

6. Remove from Heat and Pour:

   Once the desired consistency is reached, remove the mixture from heat.

   Quickly pour the bioplastic mixture into your mold or onto a flat, non-stick surface, as it will begin to set as it cools.

7. Cool and Set:

   Allow the bioplastic to set at room temperature for 24-48 hours, depending on thickness. For faster drying, you can place it in a well-ventilated area.

Three days later

Challenges Faced

One major challenge I encountered during the experiment was the unexpected disposal of my bioplastic sample by another student who was unaware of the ongoing project. After five days of promising progress, the partially formed bioplastic was mistakenly thrown away, interrupting the entire process before I could analyze the final results. This incident emphasized the importance of clearly labeling experiments and improving communication within shared lab spaces to prevent similar misunderstandings in the future.

Exploring the Potential of Tree Tomato Waste for Sustainable Biomaterials

After discovering that tree tomato waste is a promising resource for biomaterial development, I was inspired to take my experiments further. I loved the potential it showed in my initial trials, and I am eager to modify the recipe to explore different properties that could enhance its application. My goal is to experiment with various natural additives and substitutes to achieve improved elasticity, tensile strength, and durability, making the material more versatile. Additionally, I want to experiment with natural colorants and essential oils to enhance its aesthetic appeal and scent, creating a more appealing and functional bioplastic. This new direction excites me, as it allows me to push the boundaries of sustainable design and discover innovative solutions for eco-friendly products.

Modified recipe

Here's a modified recipe for tree tomato bioplastic using alternative, more accessible, and biodegradable ingredients while maintaining key properties like flexibility, strength, and durability.

Ingredient	Amount	Purpose/Action
Tree Tomato Waste	100 grams	Natural polymer source
Glycerol (Glycerin)	1–2 tablespoons	Adds flexibility and retains moisture
Gelatin	10 grams	Forms gel and provides structure
Water	100 ml	Blends and dissolves ingredients
Vinegar (optional)	1 teaspoon	Adjusts pH and improves durability
Cornstarch	10 grams	Adds film strength and elasticity
Egg white	5–10 ml	Enhances elasticity and acts as a binder
Gelatin & Glycerin Mix	5–10 grams	Improves flexibility and water solubility
Sodium Alginate	2–5 grams	Provides structural support
Beeswax	5 grams	Adds water resistance and improves texture

Instructions

Step 1: Prepare Tree Tomato Paste

• Blend the tree tomato waste (100 grams) with 100 ml of water until you achieve a smooth consistency.

• Strain the mixture to remove large fibers if necessary, ensuring a smooth paste.

• Set aside the paste for later use.

Step 2: Mix Dry Ingredients

• In a saucepan (off heat), combine:

  • 10 grams of gelatin*
  • 10 grams of cornstarch*
  • 2 to 5 grams of Sodium alginate

• Add about 50 ml of water (half the total amount) and stir thoroughly until all the dry ingredients are fully dissolved.

• Gradually add the remaining 50 ml of water, continuing to stir until a uniform mixture is achieved.

Step 3: Heat the Mixture

• Place the saucepan on medium heat and stir constantly to prevent clumping.

• Once the mixture starts to thicken, add:

• 1 to 2 tablespoons of glycerol (glycerin) for flexibility and moisture retention.

• 1 teaspoon of vinegar (optional) to adjust pH and improve durability.

• Continue stirring and heating gently for about 5-10 minutes, ensuring it becomes smooth and slightly thickened.

Step 4: Incorporate Binding Agents

• Gradually add eggwhite of 1 egg while stirring continuously to avoid lumps.

• Stir in 5 to 10 grams of the gelatin & glycerin mix, ensuring it blends evenly to enhance flexibility and water solubility.

• Continue cooking and stirring for an additional 5 minutes, allowing the mixture to homogenize.

Step 5: Add Wax

• In a separate small pan, melt 5 grams of Beeswax over low heat until fully liquefied.

• Slowly pour the melted wax into the heated mixture while stirring continuously.

• Stir for another 3-5 minutes until fully incorporated and smooth.

Step 6: Pour and Dry

• Remove the saucepan from heat and immediately pour the mixture onto a flat surface or into molds, spreading it evenly.

• Allow the mixture to cool at room temperature for about 30 minutes.

• Leave it to air dry for 24-48 hours, or use a dehydrator set at 40°C to speed up the drying process.

Step 7: Final Touches

• Once dried, gently remove the bioplastic from the surface or mold.

• Test for flexibility and durability; store in a cool, dry place.

Expected Properties:

• Flexibility: Glycerol and egg white improve elasticity.
• Durability: Beeswax enhances water resistance.
• Eco-friendliness: All ingredients are biodegradable and non-toxic.
• Customization: You can adjust glycerin for softness or starch for firmness.

SUMMARY OF TREE TOMATO RECIPE

PLASTIC TYPE	ALGINATE	GELATINE	AGAR	STARCH	TREE TOMATO
POLYMER	4g	48g	10g	60g	100g tree tomato waste, 10g gelatin, 10g cornstarch, 2–5g sodium alginate
SOLVANT	200mL water	240mL water	300mL water	300mL water & 60mL vinegar	100mL water + 1 tsp vinegar (optional)
PLASTICIZER	8g glycerine	R:0g; N:24g; E:48g	R:4g; N:16g; E:32g	R:0g; N:40g; E:80g	1–2 tbsp glycerol, 5–10g gelatin & glycerin mix, 5–10mL egg white
HEAT	No heat, solidify with calcium chloride	Heat (no boiling)	Slow heat until smell changes	Heat then bake	Gentle heat, stir continuously (no boiling), then air-dry or bake
ADDITIVES / COATING	—	—	—	—	5g beeswax for water resistance & texture

Ripe banana Bioplastic

Ingredients

1. Ripe Banana (mashed and strained) – 200 grams (natural polymer source)
2. Water – 200 ml (to dissolve ingredients)
3. Glycerol (Glycerin) – 4 tablespoons (for flexibility and moisture retention)
4. Agar Powder – 20 grams (for gel formation and structure)
5. Cornstarch or Tapioca Starch – 30 grams (for strength and elasticity)
6. Honey – 2 tablespoons (for elasticity and moisture balance)
7. Vinegar (optional) – 1 teaspoon (to adjust pH and increase durability)

Instructions

Step 1: Prepare the Banana Paste

1. Mash 200 grams of ripe banana and blend with 100 ml of water until a smooth paste forms.
2. Strain to remove large fibers for a smoother texture.
3. Set aside.

Step 2: Mix the Dry Ingredients

1. In a saucepan (off heat), combine:
2. 20 grams of agar powder
3. 30 grams of cornstarch or tapioca starch
4. Add the remaining 100 ml of water, stirring thoroughly to dissolve the powders.

Step 3: Heat the Mixture

1. Place the saucepan over medium heat, stirring continuously to avoid lumps.
2. Once the mixture begins to thicken, add:
3. 4 tablespoons of glycerol
4. 1 teaspoon of vinegar (if using, for increased durability)
5. Continue stirring for 7-10 minutes until the mixture becomes smooth and slightly thickened.

Step 4: Add Honey for Flexibility

1. Reduce heat to low and slowly stir in 2 tablespoons of honey.
2. Mix well for another 5 minutes to ensure it’s evenly incorporated into the mixture.

Step 5: Pour and Dry

1. Remove the saucepan from heat and pour the mixture onto a flat, non-stick surface (such as a silicone sheet).
2. Spread it evenly to the desired thickness.
3. Allow it to cool at room temperature for about 30 minutes.
4. Let it air dry for 24-48 hours, or use a dehydrator at 40°C to speed up the drying process.

Final Processing:

1. Once fully dried, gently peel off the bioplastic from the surface.
2. Test for flexibility and durability.
3. Store in a cool, dry place to avoid moisture absorption.

Algae String Bioplastic

🧪 Introduction

Algae string bioplastic is a sustainable and biodegradable material derived from seaweed or algal extracts, such as agar or sodium alginate. These natural polymers can be processed into flexible, string-like bioplastics suitable for use in fashion, packaging, or prototyping. This innovative approach offers an eco-friendly alternative to petroleum-based plastics by harnessing renewable marine resources.

🧂 Basic Ingredients

Ingredient	Amount	Purpose
Sodium Alginate	2–5 grams	Main polymer derived from algae
Water	100 ml	Solvent
Glycerol	1–2 tablespoons	Plasticizer to increase flexibility
Calcium Chloride	1–2% solution (bath)	Cross-linking agent to solidify alginate
Optional: Dye	A few drops	For coloring the bioplastic string

⚙️ Required Tools

Tool	Purpose
Beaker or Bowl	To mix the ingredients
Spoon or Stirrer	For stirring the solution
Syringe or Pipette	To extrude the bioplastic in string form
Container with CaCl₂	Acts as a hardening bath to shape the strings
Gloves	For safety when handling calcium chloride

🔬 Process

Step 1: Prepare the Alginate Mixture

Dissolve sodium alginate in water and stir until fully blended. Add glycerol for flexibility and optional dye for color.

Step 2: Extrude into Calcium Bath

Use a syringe or pipette to drop or extrude the mixture into a bath of calcium chloride. The ions in the CaCl₂ cause the alginate to instantly gel into string form.

Step 3: Rinse and Dry

Remove the string bioplastic from the bath, rinse it in clean water, and let it dry at room temperature.

My Grown Material Recipe Using Pineapple Bacteria & Rice Water

I wanted to create a sustainable bioplastic-like material using natural, zero-waste ingredients. Instead of using kombucha or lab-grown bacteria, I made my own bacterial culture from pineapple peels — and it worked beautifully! Here's the full process I followed:

🍍 Step 1: Making My Pineapple Bacteria Starter

I started by fermenting pineapple scraps: - I took a few fresh pineapple peels, chopped them into small pieces, and placed them in a clean glass jar. - I added about 2 tablespoons of sugar and enough clean water to cover the peels. - I covered the jar with a breathable cloth and left it in a warm, dark spot. - After about 4 days, the liquid started to smell sour and fruity — like mild vinegar. That’s when I knew the bacteria had developed. This was my natural inoculum!

🌾 Step 2: Preparing the Nutrient Medium with Rice Water

To grow the material, I needed to feed the bacteria: - I collected 500 ml of rice water (from rinsing rice before cooking). The cloudier, the better! - I added 40 g of sugar to the rice water and boiled the mixture for about 8 minutes to sterilize it and dissolve the sugar. - After boiling, I let the mixture cool completely to room temperature.

🍋 Step 3: Adjusting the pH

To prevent unwanted bacteria or mold: - I added 10 ml of vinegar (I used apple cider vinegar) to the cooled rice water. This lowered the pH and made it safe for the good bacteria to thrive.

🧫 Step 4: Inoculating the Medium

Once everything was ready: - I poured the sweetened, acidic rice water into a clean container. - Then, I added about 80 ml of my pineapple starter liquid — just the fermented juice, not the peel. - I gave it a gentle stir (without shaking too much), then covered the container with a cloth secured with a rubber band to let it breathe.

🌡️ Step 5: Fermentation

• I placed the jar in a warm, undisturbed place (around 27°C).
• After about 7 days, I noticed a thin, transparent film starting to form on the surface.
• I let it continue growing for a total of 12 days, until the cellulose was thick enough (about 7 mm).

🧼 Step 6: Harvesting the Grown Material

• I gently lifted the gel-like sheet from the container.
• I rinsed it carefully in clean water to remove the sour smell and extra sugars.
• It was soft, flexible, and had a skin-like texture.

☀️ Step 7: Finishing

Once it fully formed and dried, we carefully remove them from the baking paper. This step needs to be done gently to avoid breaking the delicate structures.

References

1. Bioplastic-made-up-of-fruit

2. 303-banana-plastic