Making Edible Bioplastic from Seaweed for less than ₹80 ($1)

Red Algae

This article outlines the chemical properties of components I used to make edible bioplastics from red algae for less than 1 USD for 5400cm² of material (check out the picture at the bottom)

Note: Not all the bioplastic in this version was recovered due to mistakes I made with the mold (more about this at the end of the article)

1/ Gelatin (C₁₀₂H₁₅₁N₃₁O₃₉)

Gelatin is created through the partial breakdown of collagen (it has a triple helix), resulting in a mixture of peptides and proteins. It has a strong affinity for water and acts as a stabilizer since it’s a hydrocolloid (a solid substance that disperses in a liquid medium).

Collagen to Gelatin

2/ Propane-1,2,3-triol / C₃H₈O₃

This compound acts as a plasticizer and improves the ability of bioplastics in absorbing water as a crystal-forming agent. It’s used for added strength and polymerization of the monomers present in the reaction carried out.

the 3 Alcohol functional groups make it hydrophilic

3/ Phycolloids from Red Algae Gelidium/Gracilaria (C₁₄H₂₄O₉)

Red seaweed © Gavin Maneveldt

Red Algae is known for their distinctive reddish hue caused by pigments such as phycoerythrobilin, phycocyanobilin, phycourobilin, and phycobiliviolin that absorb blue light (and reflect red).

They’re widely used as a thickening/gelling agent and are mainly known for their ability to form films. Other types of seaweed-derived polysaccharides, such as agar and carrageenan, are famous for their ability to create edible films.

Agar Agar

The natural biopolymer agar-agar is isolated from the cell wall of some species of red algae, primarily from the genera Gelidium and Gracilaria(Ogonori). Its two major components are agarose and agaropectin. Agarose is a polysaccharide material composed of a linear polymer composed of the repeating unit agarose. This disaccharide is composed of D-galactose and 3,6-anhydrous-L-galactopyranose.

Agaropectin, the other principal component of agar, is a mixture of smaller heterogeneous molecules made up of D-galactose and L-galactose and heavily modified with acidic groups such as sulfate and pyruvate. Agarose is separated from agar through the removal of agaropectin.

Properties of Geladium Extract

• It is a hydrophilic colloid that has the capability of forming reversible gels rapidly and needs to be mixed or hydrated in water in order to be activated to form a gel.
• It cools at room temperature (32C). has a boiling point of 90C and a Melting point of 198C. Ie, it’s heat-sealable which makes it a good application for the food packaging industry.
• The material is subject to Syneresis. It means that the gel shrinks and becomes denser (which is good since it’s losing the water it holds), or can lead to the formation of liquid pockets within the gel (not good + leads to the final product being sticky).

The dried form of Agar Agar (fun fact: it looks and feels a lot like plastic except for the fact that it isn’t waterproof)

4/ Water

It acts as a solvent and helps denature the solution with heat to form hydrogen bonds and helps in the purification of solvents.

5/ Food color (optional)

Here are some natural dyes that can be used to dye the bioplastic:

• Beet juice is a good source of red and yellow pigments known as betalains
• Henna contains the pigment lawsone, which yields a reddish-brown color
• Spirulina is symbiotic, multicellular, and filamentous microalgae from which blue-green can be extracted
• Saffron exhibits an orange-ish hue due to the carotenoid chemical crocin present in it.
• Biomass of Cyanobacteria gives out blue dye because of its abundance of phycocyanin.

Version 1 of my bioplastic :D

Characteristics of the Current Version

It’s Waterproof (doesn’t absorb water after it dries), Flexible, Lightweight, Biocompatible/Biodegradable, Cheap, and Non-Toxic. The resulting plastic can actually be eaten without any problems — as long as it’s made in sterile conditions.

Disadvantages

1. It can’t hold too much weight and doesn’t have remarkable mechanical properties.
2. The material itself is relatively flexible, which is good, but it’s also sticky (I accidentally miscalculated proportions)
3. These composite materials cant be formed into pellets. Hence it can’t be used for injection molded and isn’t compatible with standard processing machinery.
4. There’s a fair gap between this Version and potentially commercially viable ones because of the physical characteristics ( flexible but not enough, firm but not enough, and sticky)
5. I had a lot of trouble extracting the starch from dry seaweed since it was too dehydrated and wouldn’t seem to melt (it can be skipped if you get the powder form of the extract)
6. I didn’t use a dehydrator/radiator to dry the material — it would’ve helped a lot with the process (better efficiency and speed)

How this Version can be Improved

1. Adding plasticizer (A substance that increases the plasticity and moldability of a material.)
2. By using International grade chemicals (from Sigma Aldrich etc.) to make the production process standard
3. Controlling syneresis using a Dehydrator/Radiator for the drying process. I used the most cost-effective non-efficient method of *evaporation* :D and it didn’t help with preventing gel sacs.

Another version (different measurements, lesser seaweed)

Next Steps

• Do a technical post-mortem of the experiment for future improvement and iteration.
• Make a video explaining this experiment. Follow me on YouTube to get the video as it’s released.
• Make a polymer + plastic map on Miro.
• Work on a literature review about a veryyy cool emerging field within the world of plastics. Keep an eye out ;)

References

1. Lee, R.E. (2008). Phycology (4th ed.). Cambridge University Press. ISBN 978–0–521–63883–8.
2. Taxonomy Browser:: Algaebase. (2019). Retrieved from Algaebase.org website: https://www.algaebase.org/browse/taxonomy/?id=97240
3. Pascher, A. (1914). “Über Flagellaten und Algen “. Berichte der deutsche botanischen Gesellschaft 32: 136–160.
4. The NCBI taxonomy database. Retrieved from http://www.ncbi.nlm.nih.gov/taxonomy.
5. Taxonomy Browser:: Algaebase. (2019). Retrieved December 6, 2019, from Algaebase.org website: https://www.algaebase.org/browse/taxonomy/?id=97240
6. Rhodophyta. Retrieved from://www.eol.org/pages/4524/overview.
7. De Clerck, O., Bogaert, K. A., & Leliaert, F. (2012). “Diversity and Evolution of Algae”. Genomic Insights into the Biology of Algae. Advances in Botanical Research. 64. pp. 55–86
8. McFadden, G.I. (2001). “Primary and Secondary Endosymbiosis and the Evolution of Plastids”. Journal of Phycology. 37 (6): 951–959.
9. https://www.researchgate.net/profile/Ching-Lee-Wong-2/publication/311772352_somche_2015_paper_1/links/585a221008aeabd9a58b512f/somche-2015-paper-1.pdf
10. https://www.jetir.org/papers/JETIR1903D56.pdf
11. Robert G. Sheath, John D. Wehr, in Freshwater Algae of North America, 2003
12. https://ucmp.berkeley.edu/protista/rhodophyta.html
13. Chandran J, Nisha P, Singhal RS, Pandit AB. Degradation of color in beetroot (Beta vulgaris L.): a kinetics study. J Food Sci Technol. 2014 Oct;51(10):2678–84.
14. Shin JW, Choi JY, Huh CH, Na JI. Two Cases of Pigmented Contact Dermatitis Caused by Pure Henna Hair Dyes. Ann Dermatol. 2018 Dec;30(6):735–737.
15. Vo, Thanh-Sang (2015). Handbook of Marine Microalgae || Nutritional and Pharmaceutical Properties of Microalgal Spirulina. , (), 299–308.
16. https://www.webexhibits.org/causesofcolor/5D.html#:~:text=The%20relative%20abundance%20of%20phycobilin,explain%20the%20color%20of%20cyanobacteria.
17. https://www.researchgate.net/publication/319385214_Gelatin-Based_Hydrogels_for_Organ_3D_Bioprinting