Have you ever heard of a class of natural chemical compounds called “biopolymers”?   

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Biopolymers are molecules joined together in a long chain that are produced by the cells of living organisms. Examples of natural biopolymers include substances such as proteins, natural rubbers, starches, and cellulose. The solid parts of all plants are made up of biopolymers. The other group of biopolymers are synthesized polymers in living cells; the most popular example of this kind of biopolymers is Polyhydroxyalkoanates (PHAs).

By using biopolymers instead of petroleum-based synthetic polymers in the manufacturing process, America and the world would be able to replace virtually most every plastic product used in daily life with a non-polluting, biodegradable version.  

That would mean an end to the millions of tons of computer casings, plastic bottles, plastic spoons, knives, forks, bags, straws, and takeout containers overflowing our landfills and clogging our waterways.

“Unfortunately, at the moment, biopolymer products are not cheap to manufacture compared to synthetic plastic products, so our processing of biopolymers is concentrated on high-value applications like the biomedical and automotive industries,” says Dr. Thushan Withana-Gamage, KeyLeaf’s Principal Scientist for Innovation and Technology.

Biopolymers are currently being used in:

Biomedical Applications: 

Both natural and synthetic polymers are used in medical prosthetic applications like heart valves, stents, cartilage scaffolds, joints, making of artificial skin, blood vessels, membranes, sutures, and also in nanosystems for drug delivery. As the nano delivery of drugs to target organs becomes standard protocol, the importance of biodegradable polymers in the field of medicine is skyrocketing.(1)

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Industrial Use: 

Biopolymers are used as industry-standard materials due to their unique features. Interior and exterior parts, electrical components, engine, exhaust, steering wheels, and other parts composed of biopolymers are used in the automotive industry.

Agricultural/Fishery:

Biopolymers are used in making fishing lines, fertilizers, beehives, nets, traps, etc.

Electronics:

Biopolymers are used in the manufacture of audio devices, printed circuit boards, insulated wires, cables and other electronic devices.

Cosmetics:

Used in the formulation of soaps, sunscreen, hair products and creams.

EXTRACTING THE BIOPOLYMER

“Biopolymers are created inside plants or inside prokaryotic organisms such as bacteria – after which they must be extracted and purified,” says Dr. Withana-Gamage. “ We can perform the extraction in one of three ways. The first way is solvent extraction. KeyLeaf has a solvent extraction area which has extensive Class 1, Division 1(C1D1) safety features for handling food grade solvents. KeyLeaf also boasts a unique specialty -- we can reclaim and reuse our solvent.  This is good for the environment and good for cost reduction - and it’s a big deal in the industry.” 

Dr. Withana-Gamage says the second method of extraction is a digestion method, where various chemicals, surfactants, and enzymes are used to digest growth media (e.g., bacteria) or digest the cell walls of plant material, separating out the biopolymer. 

”We put the plant material in a reactor, mix it with enzymes and various chemicals then put it in a centrifuge to separate. We can do this in KeyLeaf’s Secondary Processing Area.”

‘The third method, which is the most popular, is the mechanical pulverization of cells containing biopolymers and do the extraction using various means. Mechanical destruction of the cells can be achieved by a process called bead milling. The results of bead milling are very consistent and predictable and very easy to scale up. We have equipment that can run up to 300 kg per hour and process up to 7 metric tons of biomass per day based on the process,” says Dr. Withana-Gamage.   

Dr. Withana-Gamage says after extraction, the biopolymer undergoes centrifugation and/or filtration to remove the cell debris, and then a washing stage using a solvent wash to get the purity of the biopolymer up to a very high level, 98 to 99% is achieved. After drying, the resulting byproduct is a very nice, versatile white biopolymer ready for application, whether for the plastic spoon making industry or for the medical industry to make sutures or other medical devices.” 

“When you release these biopolymers o the environment, they are able to quickly degrade after exposure to environmental factors such as moisture, heat, sunlight and temperature. At the moment, the group of biopolymers called PHAs (polyhydroxyalkanoates)demonstrates the greatest biodegradability and is utilized in thousands of applications.”

“With increasing public awareness of the mounting crisis in plastic waste, in the next few years, I predict KeyLeaf will be seeing more and more inquiries regarding biopolymer extraction and purification,” says Dr. Withana-Gamage.

REF:

1) Biomedical Applications of Polymers - An Overview

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