Study questioning eco-credentials of bio-based plastic flawed – NatureWorks

By Rory Harrington

- Last updated on GMT

Related tags: Polylactic acid, Lactic acid

Study questioning eco-credentials of bio-based plastic flawed – NatureWorks
A recent study that found no bio-based plastics are fully sustainable contained significant inaccuracies and was based on out of date information, according to the leading manufacturer of one of the materials covered in the research.

US-based company NatureWorks, which produces more than 90% of global polylactic acid (PLA), told FoodProductionDaily.com the paper from the University of Massachusetts-Lowell contained erroneous data about the bio-based plastic.

The research, published in the Journal of Cleaner Production, raised a number of environmental and occupational health and safety concerns about the production of a raft of biobased plastics - including PLA, starch (pure thermoplastic starch: TPS), polyhydroxyalkanoates (PHAs), and nano-biocomposites.

NatureWorks said much of the research was sound but that part of the paper identifying methodologies where the biopolymers industry could be more sustainable, “needs clarification and correction of factual errors”.

PLA concerns

The researchers listed specific concerns about PLA and suggested techniques that should be introduced improve its sustainability.

But Steve Davies, NatureWorks director, marketing & public affairs, said the concerns about PLA raised by the UMass-Lowell group were not based on current data and did not represent existing industry practice.

The study highlighted the risk from toxic organotin compounds which it said are used in the production of PLA. However, Davies said the company does not use any of these compounds in the production of its PLA brand, Ingeo.

Similar concerns raised over 1-octanol, claiming it is used as a polymerization initiator, are also inaccurate for the same reason, he added. The group also failed to recognise other improvements made by the industry.

“The study recommends further technology advances or alternatives to reduce or replace the formation of co-products during the lactic acid fermentation process,”​ said Davies. “It does not take into account the substantial technology advances already long in place at NatureWorks.”

Since 2008, the firm has employed a more efficient lactic acid fermentation process that substantially reduces the formation of the lactic acid co-products, said the marketing and public affairs director.

Unvetted statements

The scientific team didn't vet or confirm their findings on PLA with NatureWorks, said the company, which said it is the “only world scale manufacturer of polylactides”.​  

Many of their recommendations for improvements “are all things which the industry has long recognized, and either already implemented, or already has underway”, ​said Davies.

The use of agricultural or industrial by-products as feedstocks for bioplastics as suggested by the study is already a main focus for the industry. The company said it has also done much work on the introduction of third party certification schemes to promote use of sustainable agricultural methods in growing crops for bioplastics.

Recommendations to implement GMO offsetting programmes by purchasing offsets equivalent to the amount of feedstocks used have already been introduced, said Davies.

No process or material impact neutral

NatureWorks said it had achieved an independently assessed Cradle-to-Cradle certification for its entire family of PLA grades - issued by McDonough Braungart Design Chemistry.

The Cradle to Cradle certification is a multi-attribute program that assesses products for safety to human and environmental health, design for future use cycles, and sustainable manufacturing processes, explained Davies.

The company pointed out that all material and processes have an environmental impact and all involve a trade-off.

“Biopolymers, as have been shown in third party reviewed research, score extremely high on some aspects of manufacture as compared to fossil carbon plastics,”​ it added. “On other items, for example land usage, they score lower. And in that instance it’s because fossil carbons have nothing to do growing crops. Based on all of the factual production information available today and the best independent research basing a biopolymer on renewable resources is good society, business, and the environment. “

This article has been amended as the original version identified the research team as coming from UMass. In fact, the scientists are based at University of Massachutts-Lowell.

Related topics: Processing & Packaging

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2 comments

what are the numbers?

Posted by Allan Griff,

I don't care who is wrong and who is right on minor issues as catalysts. What is the environmental impact of PLA including energy needs from planting to polymer and including disposal of ag wastes? Then compare PLA commercially viable formulations (not just the resin) to competitive materials, not per lb but per product and/or property.
Leave aside for the moment the issues of PLA messing up the PET recycle stream, the return of CO2 to the atmosphere as a degradation product, the toxicity if any of the degradation products, the higher cost of PLA, and the (non)prevalence of industrial-scale, profitable composting in most of the USA.
What are the numbers?

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What is oranotin?

Posted by Matt Moore,

What is oranotin, I have never heard of such a thing?
(Ed - We meant 'organotin' of course- apologies for the error)

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