A greater understanding of pectin can inform efforts to break down plants into renewable fuels and bioproducts.

Pectin research offers promise for medical applications of biofuel byproducts

Scientists working through the Center for Bioenergy Innovation (CBI) are researching the role and behavior of pectin, which makes up 30 percent of some plant primary cell walls and has some unusual properties. A greater understanding of this component of plant biomass could make it easier to break down plants into renewable fuel and profitable bioproducts. Unused biomass, such as leaf residues from agricultural plants, are especially rich in pectin.

Composed of strings of sugars, pectin is vital for plant cell growth. It is also an adhesive, able to immobilize substances within a gel structure. These paired abilities mean pectin could be used to trap molecules or growth factors within a gel, making it attractive for targeting drug delivery, facilitating tissue engineering and healing wounds in humans. The adhesiveness of pectin is already important for production of commercial gels, coatings, and thickeners. Developing high-value commercial applications for pectin could create an additional income stream for biofuel refineries, making renewable fuel more cost-effective.

Dr. Debra Mohnen, professor of Biochemistry and Molecular Biology at the University of Georgia Complex Carbohydrate Research Center, contributed her expertise in pectin to a recent study of the physical conditions that influence the entanglement of pectin molecules. Researchers hypothesized that entanglement, combined with wetting the contact area between surfaces, is a necessary step for subsequent chemical reactions – in this case, binding the moist lining of some organs and body cavities.

Collaborators at Harvard Medical School, University Medical Center of the Johannes Gutenberg-University, and the Translational Lung Institute at the University of Heidelberg pursued the research as part of a larger effort to understand whether pectin could be used in medical applications, such as sealing lung perforations that occur during surgery. Through CBI, Mohnen provided the team with a better understanding of which pectins were involved, and she was able to probe in detail the molecular structure of the entanglement mechanism. The Joint BioEnergy Institute and Lawrence Berkeley National Laboratory also contributed understanding of a pectin biosynthetic enzyme and biotechnical applications of cell wall polymers.

Research partners conducted lab experiments to understand how the entanglement of pectin molecules is affected by conditions like water movement, temperature, and the extent of compression.

Mohnen said the results provide new insights into the roles of water and force in entanglement of pectin molecules. A promising finding was that pectin entanglement occurred at room temperature, making it potentially compatible with use in surgery and living tissue.

Improved understanding of how pectin operates also has broad implications for other CBI priorities, such as improving and more fully using biofuel feedstocks. Some of Mohnen’s previous research has shown that by reducing pectin biosynthesis in poplar and switchgrass, the crops’ yields and sugar release for ethanol production increased dramatically and lasted over multi-year field trials.

Mohnen’s current research builds on the entanglement results, examining how pectin might be contributing to the challenges involved in breaking down cellulosic biomass. The same characteristic that makes pectin bioadhesive could be contributing to the difficulty in deconstructing plant cell walls for making biofuel. Further research could provide scientists with new tools to engineer biomass so both the pectin and sugars within the plant cells are more accessible for commercial use.

CBI at Oak Ridge National Laboratory is one of four Department of Energy Bioenergy Research Centers focused on advancing biofuels and bioproducts for a vibrant domestic bioeconomy. CBI is accelerating the development of bioenergy-relevant plants and microbes to enable production of drop-in sustainable aviation fuel, bioproducts that sequester carbon, and sustainable replacements for plastics and other environmentally harmful products. CBI research is supported by the Biological and Environmental Research program in DOE’s Office of Science.