Scientists are using enzymes to build new materials from the polysaccharides available in plant biomass.

Taking the pulse of polysaccharides: Evaluating approaches to making high-value bioproducts

Scientists collaborating through the Center for Bioenergy Innovation recently compiled research about new ways to turn plant polymers into environmentally friendly products. These plant-based materials are carbon-neutral, renewable and biodegradable, making them ideal for replacing petroleum-based plastics and chemicals. They could be manufactured on their own or alongside biofuels in a refinery, using plant feedstocks such as grasses or crop residues.

However, the polymers extracted from plants are complex and vary. Small structural differences can have a big impact on their behavior. This study, published in ACS Sustainable Chemistry & Engineering, synthesized research from around the world about how to build polymers called polysaccharides – chains of sugars – using enzymes from plants and microbes. Learning more about the structure and properties of polysaccharides is the first step in constructing them, either by using chemical synthesis in the lab or by using the enzymes that naturally modify the structure and properties of polysaccharides from plant feedstocks.

“We wanted to explore where the technology is right now for using these enzymes and to give a road map for what needs to be improved upon in the future,” said the study’s lead author Peter Smith, a researcher at the National Renewable Energy Laboratory. Using enzymes is promising because the technology exploits natural systems and processes and may be less expensive and labor intensive than using chemical methods.

“These methods give us the ability to fine-tune the polymer’s structures and how they interact in these complex systems,” Smith said. “Synthesizing them in controlled ways would really help build in those material properties that we need to make better products.”

Partners in the study included the University of Georgia, which contributed its knowledge of how polysaccharides are made and function in plants; the Max Planck Institute in Germany, which has experience making polysaccharides in the lab using a combination of chemical synthesis and enzymes; and the University of Wuerzburg, which provided expertise in engineering and in the relationships between enzyme structure and functions.

Polysaccharides are both biodegradable and safe for human consumption, making them great candidates for products for medical applications or as edible plastic food packaging. They are already added to products ranging from yogurt to skin moisturizer.

Although more experimentation is needed to make these high-value products efficiently and economically, the study demonstrated the potential of manipulating the diverse and abundant polymer building blocks available in biomass.

The Center for Bioenergy Innovation (CBI) at ORNL is one of four DOE 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.