The Many Faces of Biopolymers

Honored Contributor
0 0 3,231

Contributed by Dr. Masha Petrova, MVP Consulting Solutions, LLC

What exactly is a "Biopolymer"? Is your definition of this term the same as that of your colleague down the hall? "Biopolymer" is a relatively new term currently used to describe everything from biodegradable plastic bottles, to bags made out of corn, to biocompatible parts used in knee replacement surgeries, to proteins.

As the marketing trend for all things “green” continues to climb, it seems that everything but the kitchen sink gets thrown into the “biopolymers” bucket. To further complicate things, biopolymer products span a variety of seemingly unrelated industries, such as commodities (e.g. packaging, containers and additives), medical applications (e.g. drug casings and prosthetics) and food applications (sugar and starch are in fact biopolymers).

So what is the “correct” definition of a biopolymer?  Wikipedia will have you believe that a biopolymer is a type of polymer produced by living organisms, in other words a macromolecule produced in nature. While that statement is technically correct, this is only a part of the definition. According to Dr. Pat Smith, a Sci-MindTM expert and a research scientist at the Michigan Molecular Institute, some describe biopolymers not only as materials of a "green birth" but polymers with a "green death" as well. In addition to the bio-derived definition, a polymer is considered to be a "biopolymer" if it is said to be biodegradable according to international standards on biodegradability (which, by the way, are also ever-changing). This means that a biodegradable polymer material created solely from fossil fuel feedstocks may, in fact, be described as a "biopolymer".

Which means that a bottle made 100% from corn starch but that happens not to be biodegradable (and might sit in a landfill for decades) and a bottle that is made from fossil fuel feedstock but biodegrades under similar conditions - are both "biopolymer" products. So which biopolymer side is "greener"?

Dr. Smith has seen his share of biopolymer companies emerge, merge, and disappear. He was involved in the Cargill Dow joint venture that launched NatureWorksTM poly(lactic acid) and in the Metabolix joint venture with Archer Daniels Midland which attempted to commercialize polyhydroxyalkanoates. Dr. Smith has a message for the biopolymer industry: "Stop wasting money trying to create novel commodity polymers from bio-sources, but instead, focus on synthesizing traditional and well-established polymer materials from bio-based monomers."

According to Dr. Smith, developing the market for new polymer materials is significantly more difficult than inventing the technology to produce them. Monomers for conventional polymers like poly(ethylene), poly(acrylic acid) and poly(ethyleneterephthalate) can be derived from bio-sources and already have a commercial outlet. They simply need to meet price and purity metrics to succeed. This latter strategy is well defined and is faster to the market.

In contrast, Dr. Richard Gross, a Professor at Rensselaer Polytechnic Institute and a Sci-MindTM expert, believes that both routes are potentially viable and have their own challenges. For example, developing conventional monomers from biobased feedstock has been slower than anticipated due to the challenge of competing strictly on cost at equivalent performance. Dr. Gross believes there is plenty of room for new innovations by using the functionality inherent in biobased feedstock to develop new materials.

While the commodities industry might be concerned with high yields and low cost-per-unit, the situation could not be more different for the medical industry research. Professor Sujata Bhatia, the assistant director for undergraduate studies in Biomedical Engineering ... and a Sci-MindTM expert, works with students to develop naturally-derived biopolymers for medical applications in wound healing, drug delivery, and tissue regeneration.

Dr. Bhatia says that for biomedical applications, where many materials are custom-tailored for a handful of patients, the cost-per-unit is not much of a concern. However, the biocompatibility and specialized properties of a particular material certainly are.

Not only do biopolymers have such varying roles in different industries, but with evolving globalization of economy and research, paying attention to how biomaterials are positioned around the world is becoming more relevant.

Dr. Bhatia's advice to professionals working in the medical field concerns globalization issues: "We need to recognize that countries in Africa, Southeast Asia, and Latin America have something unique to contribute to biomedical materials. Because these countries have diverse and abundant agricultural materials, they can develop biopolymers and participate in the biomedical revolution in ways that were not previously possible."

No matter in what line of work you might come in contact with biopolymers, one thing always remains constant– the importance of solid knowledge of fundamental science. Dr. Tim Long, a professor of Polymer Chemistry at Virginia Tech and a Sci-MindTM expert, knows the significance of understanding the basics. His work involves integrating fundamental research in novel macromolecular structure and polymerization processes for development of high performance macromolecules. According to Prof. Long, a good knowledge of fundamental science is essential for anyone interested in bio-derived, biocompatible or biodegradable polymers.

For those working in biopolymers, that knowledge becomes even more diverse for the "bio" counterparts of the polymer molecules. According Dr. Gross, aside from the basics of polymers science, one must be familiar with biochemical processes, such as fermentation and bio-catalysis. Dr. Gross is currently working on routes to monomer and biopolymers using cell-free and whole-cell biocatalysts. He also is an avid proponent of combining chemical and biocatalytic steps in biopolymer process development.

"The synthesis of biopolymers via biocatalytic routes requires an understanding of how cells are engineered to produce different chemicals, the properties of enzymes that are important catalysts for cell-free processes, and an understanding of fundamental principles in cell biology and biochemistry. It's critical that scientists interested in biopolymers learn the language of biocatalysis since biocatalytic processes are fundamentally important to many developments in the general area of biopolymers," says Dr. Gross.

The rapidly growing field of biopolymers is indeed exciting and diverse. In order to assure that researchers and industry professionals can stay up-to-date on the latest research trends, science fundamentals, regulations, and real-world case studies in order to be able to answer questions like those presented above, the American Chemical Society has created Sci-MindTM Biopolymers – a community based, online learning curriculum for industry professionals. This article highlights the knowledge of just a few of the experts involved in ACS Sci-MindTM Biopolymers program launching on April 7th.

Can't get enough of Biopolymers? Sign-up for the next cohort launching April 7th here:

“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.

To read other posts, go to Green Chemistry: The Nexus Blog home.

Tags (1)