US researchers challenge petroleum-based packaging with food-grade bioplastic alternative

The NSF Center for Sustainable Polymers has developed a chemical tech for producing petroleum-like liquids from plants (Credit: John Beumer).

30 Nov 2021 --- Researchers at US universities Berkeley California and Minnesota have developed a new chemical fermentation technology for producing food-grade plastic products from plant-based sources. The researchers say their development processes are now being optimized, while commercialization presents an “exciting” possibility.

The chemical technology uses a combination of fermentation and chemical refining to produce petroleum-like liquids from renewable plant sources, which can then be turned into plastic products.

The University of Minnesota researchers explain “these renewable liquids could serve as an [environmentally] sustainable replacement for today’s fossil fuels used to make everyday products like plastic containers and bags, automobile parts, lubricants and soaps.”

Meanwhile, Michelle Chang from the University of Berkeley California, tells PackagingInsights the project is presently mostly conceptual and new process ideas are being developed.

“Currently, we aren’t working on commercializing the technology, but we would be excited to do so. [The commercialization] would require an industrial partner.”

Food-grade suitable
Chang confirms the bio-petroleum could be used for food-grade packaging.

The new chemical technology can produce petroleum-like liquids from renewable plants for making plastic-based products.“Part of the reason we developed this process is that the 3-hydroxy acids we make by fermentation are easily accessible through enzymatic pathways, and we can make many different structures to tune for desirable properties.”

“Using a heterogeneous rather than enzymatic approach to producing the olefin allows us to utilize a general strategy to produce olefins from these molecules and skip the challenging protein engineering that would be required if we used an enzymatic method. These olefins could then be used for a variety of downstream reactions,” Chang elucidates.

Technical challenges
The University of Minnesota researchers explain it has been difficult for scientists to use plants as a source for plastics because they are mostly made of sugars, which are nothing like the molecules obtained from petroleum.

“The key sugar in plants is glucose, which contains too much oxygen and at six carbons is too small for many important applications. To use plants for making new materials, both problems must be solved – the conversion process needs to strip oxygen atoms from the glucose and must combine molecules to make larger products.”

Composting and recycling ideal
Chang explains composting and recycling would be the best end-of-life disposal methods for bioplastics produced with bio-petroleum.

“Currently, this is generally possible with polyesters made from the 3-hydroxy acid precursors. For polymers made from olefins, there is other research in the Center for Sustainable Polymers (US National Science Foundation) working on recycling these types of polymers by developing plastics with monomers that can ‘unzip’ the polymer or allow recycling.”Renewable liquids could serve as an environmentally sustainable replacement for today’s fossil fuels.

Looking ahead
The researchers are currently looking at producing other 3-hydroxy acid structures to produce polyester monomers and convert them to olefins.

“We hope that some of these would bring new functionality concerning recycling or degradation since that is really something important for making an environmental impact,” Chang stresses.

In a similar development, researchers at Stockholm University recently developed a lignin-based alternative that could replace conventional plastic packaging and adhesives.

Furthermore, ahead of the 16th European Bioplastics Conference taking place today and tomorrow in Berlin, market development manager for biopolymers at Kaneka Belgium, Erwin Lepoudre, argued bioplastic market growth would benefit from regulation differentiating biodegradable plastics from conventional petrochemical plastics.

By Natalie Schwertheim

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