Is ‘plant plastic’ fantastic? A guide to bio-based plastic packaging

Many ethical retailers are turning away from conventional petroleum based plastics in a bid to be more environmentally friendly. Bio-based plastics are growing in popularity as replacement packaging material. Confusingly, some companies even claim that their bio-based plastic products are 'plastic-free'. 

Ruth Walton asks, what are bio-based plastics actually made from? Are they good for the environment? And what is the best way to dispose of them?

What material is bio-based plastic made from?

Let's start with the basics: The word plastic refers to many types of synthetic material made from polymers. A polymer is a molecule with a structure made from multiple repeating units.

The raw materials used to make these polymers can be bio-based (made from plants, organisms or other biological material) or fossil-based (made from petroleum derived from fossil fuels).

The terms plant plastic, bioplastic or bio-based plastic can be used in reference to material that is completely or only partially made from renewable materials.

Four Main Types of bio-based plastic

1. One of the most common bioplastics is Polylactic acid (PLA) which is starch-based. It is used commercially in many applications such as teabags and single-use food packaging. PLA is made using fermented starch, derived from renewable raw materials such as corn, cassava, sugar beet pulp, or sugarcane. PLA is     commonly made from genetically modified (GM) plant material.

2. Cellulose-based films such as NatureFlex™  and Cellophane™  are commonly used in food packaging. These are manufactured using cellulose from wood pulp, often blended with a small percentage of fossil-based material. NatureFlex™  and Cellophane™ both use 90-99% wood pulp which has been certified by the FSC (Forest Stewardship Council)  or PEFC (Programme for the Endorsement of Forest Certification).

3. Potato starch is used to make a home-compostable wrap that is used for magazine wrappers and food waste caddy liners. Bioplast 300 is manufactured by German company Biotec.  It is over 30% bio-based and is free from GM material. It is used to wrap publications such as the Guardian Weekend Magazine.

4. A water-soluble polymer based on Polyvinylalcohol (PVOH) commonly used for detergent 'pods', is now being used as packaging by some fashion companies (Ethical cornish clothing label Finisterre now use Aquapak product Hydropol™).

There are other types of bioplastics and a huge range are in use, and even more are currently being developed. Vegans beware: newer innovations include bioplastic made from agricultural and industrial food waste such as feathers and fish scales.

As the Waste and Resources Action Programme (WRAP) document Considerations for Compostable Plastic Packaging points out that “...the term 'plastic free’ should not be applied to compostable plastics even if they incorporate 100% bio-based content”. Plastic is plastic no matter where it comes from.

The impact of using land to grow raw materials for bioplastic that could otherwise be used for growing food crops is questionable. There are other environmental concerns, such as pollution from crop fertilisers to take into consideration. With these factors in mind, a bioplastic made from industrial waste products seems to be a good solution.

What's the difference between and biodegradable, degradable, compostable, and home compostable plastic?

Biodegradable Plastic 

Although the term 'biodegradable' is defined as “able to decay naturally and in a way that is not harmful”. there are no official certification schemes to verify use of the word on product labelling.

WRAP states that; “Despite definitions being available in EU regulation (Dir2019/904), the term biodegradable is also often misused and applied to a broad range of different materials. Without a specified environment and time frame, the term is extremely vague, because a biodegradable product may biodegrade in some environments and not (in any reasonable timeframe) in others.”

Just because a product has the word biodegradable on, it doesn't mean it's ok to fling it into the hedge or put it on your compost heap. Materials labelled as biodegradable can even contain a small percentage of conventional fossil-based plastic.

Degradable Plastic

Beware of 'degradable' or 'oxo-degradable' plastics. These are conventional fossil-based plastics which have chemical additives to help them break down into microplastics faster. Oxo-degradable plastics are now banned under the EU single-use plastics ban. https://dictionary.cambridge.org/dictionary/english/biodegradable

Compostable Plastic

Compostable plastic refers to plastics that can break down in an industrial hot composting system. It can be made from renewable bio-based materials or a mixture of bio-based and fossil-based material.

Home Compostable Plastic

Home Compostable Plastic refers to plastics that will break down in a well-managed garden compost heap. It can also be made from renewable bio-based materials or a mixture of bio-based and fossil-based material.

There are several certification schemes for compostable and home compostable packaging. Look out for the TUV OK Compost logo or the Dincerto seedling logo. These both comply to European composting standards, which means that the material has been rigorously tested for disintegration time and ecotoxicity.

Is bio-based plastic always biodegradable?

No. Some bio-based plastics are as durable as conventional fossil-based plastics. The name only refers to the raw material used to manufacture the final product.

The UK Plastics Pact & WRAP document Considerations for Compostable Plastic Packaging outlines these two key facts:

  • All compostable plastics are biodegradable, but not all biodegradable plastics are compostable
  • Not all bio-based plastics are compostable and not all compostable plastics are bio-based

How should I dispose of bioplastic packaging?

If you're trying to reduce your household waste, learning how to dispose of these new materials can be quite confusing. As there are so many types of bioplastic, it is important to check for any labelling to indicate what material is used.

Some councils will accept compostable plastics with food or garden waste schemes but you will need to check with your council or service provider.     
          
Plastics marked as home compostable should be added to your compost heap. If you want to speed up the process, they can be shredded. Even a well managed compost heap may struggle to deal with a large influx of home compostable packaging. If you haven't got your own compost heap, consider asking a neighbour with a large garden or look for a community composting scheme.
          
If it is not labelled as home compostable, bio-based plastic needs to be disposed of in general household waste where it will be incinerated in an Energy From Waste scheme, or go to a landfill site.
          
Make sure that you don't add bio-based plastic to kerbside plastic recycling schemes. The material will pollute the recycling stream.

Disposable catering product manufacturer Vegware operate a close-the-loop scheme in some regions of the UK, and have partnered with Recyclebox to offer a paid-for industrial composting service. However, if you are a regular user of disposable coffee cups or other single-use catering products, it would probably be a good idea to invest in a reusable alternative

Vegware state on their website “ Incineration studies on compostable packaging from NatureWorks, a key materials supplier of ours, show that their PLA bioplastic produces more heat than newspaper, wood or food waste; also that it produces no volatile gases and leaves little residue. Some in the waste sector prefer plant-based materials over conventional plastics as they give off fewer toxic gases. In landfill, studies have shown that compostable packaging is inert and does not give off methane."

The subject of bio-based plastic is complicated, with many different factors affecting it's sustainability. While in some cases, using bio-based plastic may be a step in the right direction, it is preferable to avoid plastic packaging altogether by using alternatives such as recycled paper, or buying from refill schemes.