A bioenergy sorghum crop is harvested near College Station.

Agriculture byproducts could help produce biodegradable plastics

Image credit: Texas A&M AgriLife

Bioplastics can be created in a more environmentally friendly way from the byproducts of corn stubble, grasses, and mesquite agricultural production, according to scientists at a Texas-based research centre.

Bioplastics are biodegradable plastics made from biological substances rather than petroleum. 

The novel approach involves a 'plug-in' preconditioning process, a simple adjustment for biofuel refineries, said Joshua Yuan, a research scientist at the Texas A&M AgriLife Research facility. These 'plug-in' technologies allow for optimisation of sustainable, cost-effective lignin – the key component of bioplastics used in food packaging and other everyday items.

According to Yuan, efficient extraction and use of lignin is a major challenge for biofuel refineries. “Our process takes five conventional pre-treatment technologies and modifies them to produce biofuel and plastics together at a lower cost,” he explained.

The new method, called 'plug-in preconditioning processes of lignin', or PIPOL, can be added into current bio-refineries and is not cost-prohibitive, Yuan said. PIPOL is designed to integrate dissolving, conditioning, and fermenting lignin, turning it into energy and making it easily adaptable to bio-refinery designs.

A high-yielding perennial sorghum forage hybrid can be used as a feedstock to create bioplastics in a more economical and environmentally friendly way.

A high-yielding perennial sorghum forage hybrid can be used as a feedstock to create bioplastics in a more economical and environmentally friendly way.

Image credit: Kay Ledbetter

“Innovation is the key to achieving growth and a more widespread use of biodegradable plastics. Limited value-added products from biomass, lack of lignin use for fungible products, and overall low-value output with ethanol as primary products hinder lignocellulosic bio-refinery commercialisation,” he said. “This recent discovery will make significant strides to overcome some of these challenges.”

Yuan said the bioeconomy and bio-manufacturing sectors are a federal priority as the White House Office of Science and Technology Policy points to bioeconomy infrastructure, innovation, products, technology, and data to enhance US economic growth. The bioeconomy supports some 285,000 jobs across the nation and generates $48bn in annual revenue.

Yuan also touted the research for its environmentally friendly aspects.

He said: “We are producing over 300 million tonnes of plastics each year. It’s critical to replace those with biodegradable plastics. This work provides a path to produce bioplastics from common agriculture waste like [that from production of] corn and other grasses and wood.

“We think this research is industrially relevant and could only help enable the bio-refinery and polymer industries to [attain] greater efficiencies and economic opportunity.”

The research at the centre has already found that sustainable products such as mesquite and high-tonnage sorghum can be used as feedstock for biofuel production.

Agricultural byproducts such as corn stubble and other grasses are alternative feedstock sources for biofuel plants, Yuan said. These create potential new revenue streams for farmers and the transportation sector that transports harvested feedstock and byproduct crops to refinery operations.

“We have shown that bioplastics from lignocellulosic bio-refineries can be more economically beneficial, which opens new avenues to use agricultural waste to produce biodegradable plastics,” Yuan said. “The discovery will mitigate global climate changes via replacing fossil fuel and nondegradable plastics by renewable and biodegradable plastics.”

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