The plant-based coffee cup that still needs a factory to disappear
South African scientists can turn sugar-cane waste into a cup that breaks down; but only if it reaches an industrial composter. The country has almost none, so the greenest cup in the café may still end up as ordinary rubbish.
Published 27 October 2026 · 15:01 GMT
The summary
South African scientists can turn sugar-cane waste into a cup that breaks down; but only if it reaches an industrial composter. The country has almost none, so the greenest cup in the café may still end up as ordinary rubbish. An estimated 440,000 tonnes of plastic leak into South Africa's rivers, coastlines and open landscapes every year. CSIR scientists in Pretoria are developing biodegradable plastics from agricultural waste, including sugar-cane bagasse, forestry sawdust and chicken feathers.
The three lenses
- WestWest: Western industry analysis treats the problem as a sorting problem first and a chemistry problem second.
- EastEast: India's debate has moved further into law than South Africa's.
- Global SouthSouth: The Southern story is the one playing out in South African fields.
Key facts
- An estimated 440,000 tonnes of plastic leak into South Africa's rivers, coastlines and open landscapes every year. Daily Maverick (Oct 27, 2026)
- CSIR scientists in Pretoria are developing biodegradable plastics from agricultural waste, including sugar-cane bagasse, forestry sawdust and chicken feathers. Daily Maverick (Oct 27, 2026)
- PLA and PHA break down only under industrial composting conditions, sustained temperatures of 58°C to 60°C with controlled humidity and microbes, not in a home compost heap. Daily Maverick (Oct 27, 2026)
- South Africa has virtually no municipal industrial composting capacity able to handle post-consumer packaging at scale, the Department of Forestry, Fisheries and the Environment says. Daily Maverick (Oct 27, 2026)
- CSIR mulch films for crops such as pineapples, strawberries and cucumbers are designed to biodegrade in soil within one to three months for short-term crops, or up to 12 months for longer ones. Daily Maverick (Oct 27, 2026)
- South African agriculture uses roughly 140,000 to 180,000 tonnes of plastic products a year. Daily Maverick (Oct 27, 2026)
What did the Pretoria lab actually show?
South Africa's Council for Scientific and Industrial Research has spent years turning farm waste into plastic that is meant to disappear. In a Pretoria laboratory, principal scientist Dr Sudhakar Muniyasamy showed Daily Maverick how bagasse from sugar cane, sawdust from forestry and even chicken feathers are processed into pellets, then blown into films and moulded into cutlery, takeaway containers, straws and compostable bags. The work matters because an estimated 440,000 tonnes of plastic leak into South Africa's rivers, coastlines and open landscapes every year. The coffee cup on a café counter is the most familiar test of the idea: a plant-based cup feels like progress, and in one sense it is, since its carbon comes from crops rather than crude oil. But the laboratory result is not the same as a result in a dustbin. Whether that cup breaks down depends less on what it is made of than on where it ends up, and South Africa's waste system is not yet built for the ending the material needs.
Which plastics break down, and which only look as if they do?
Plant-based is not a single category, and the distinction decides everything. Bio-PET, made from sugar-cane ethanol, is chemically identical to conventional PET: it can be melted and recycled, but left on a roadside it survives for centuries. PLA and PHA, fermented from plant starches such as maize and cassava, are different: they can break down into water, biomass and carbon dioxide, but only under industrial composting conditions; sustained temperatures of 58°C to 60°C, controlled humidity and active microbes. A home compost heap cannot supply those conditions, and South African labelling under standard SANS 1728 says so on the product itself. The CSIR's own account of its technology is more ambitious: single-use items that biodegrade within 180 days in landfill and turn to compost within 90 days when combined with organic waste, leaving no toxic residues. Its mulch films for pineapples, strawberries and cucumbers are designed to biodegrade in soil within one to three months for short-term crops, or up to 12 months for longer ones. South African agriculture uses roughly 140,000 to 180,000 tonnes of plastic products a year, so a film that can be ploughed back into the soil instead of collected and dumped is a genuine prize; if the soil conditions match the laboratory ones.
What is still missing between the lab and the bin?
South Africa has virtually no municipal industrial composting capacity capable of handling post-consumer packaging at scale, according to the Department of Forestry, Fisheries and the Environment. Its acting chief director, Sello Molekwa, told Daily Maverick that the end-of-life treatment most biodegradable alternatives require, temperature-controlled industrial facilities, is in short supply. What happens instead is documented: compostable items buried under mixed waste in landfills such as Robinson Deep in Johannesburg or Mariannhill in Durban lose their advantage, and PLA deprived of oxygen, heat and microbes can sit intact for decades, releasing methane as it decays without air. How fast the gap closes is unknown. The department points to its 2018 guidelines on separating waste at source, a Waste Management Flagship Programme piloting organic recovery with the International Finance Corporation and the Development Bank of Southern Africa, and a Recycling Enterprise Support Programme offering grants of up to R5-million to emerging waste ventures. Producer responsibility organisation Petco is studying how far plant-based packaging has penetrated the market, to guide future policy. None of those efforts has yet produced a national composting network, and no date for one has been published.
Why does one wrong bin matter for a whole recycling stream?
South Africa has a robust recycling network for conventional PET and HDPE, and that network is exactly what a stray compostable cup puts at risk. Clear PLA looks identical to standard PET, so it slips into recycling batches; because PLA melts at a lower temperature, it chars during processing and degrades the recycled material's structural integrity. The department's warning is blunt: without separation at source and accurate sorting, compostables threaten the clean streams that make recycling work. The same logic reaches beyond waste: plastic pollution now sits among the pressures tracked in the Bureau's world barometer, and the climate thresholds that frame those pressures leave little room for solutions that only work on a label. The United Nations Environment Programme's estimate, cited by Daily Maverick, puts global plastic production above 400 million tonnes in 2025, with most of it ending up landfilled, dumped or unmanaged. A material that promises disappearance but delivers landfill methane is worse than an honest conventional plastic, because it spends consumer goodwill and policy attention without removing a single tonne from a river.
How a cup becomes a test of the whole system
The coffee cup is a useful test precisely because it is so ordinary. A cup fails or succeeds on three alignments at once: a material that genuinely breaks down under stated conditions, a collection route that keeps it away from PET recycling, and a facility that actually runs at the temperature the label promises. Remove any one of the three and the benefit collapses; into recycling contamination, into landfill methane, or into a consumer who learns to distrust every green claim that follows. Cost sharpens the point: the CSIR itself notes that bioplastics currently cost three to five times more than petroleum plastics, because biomass processing adds intermediate steps. That gap will not close on consumer goodwill alone; it closes if policy, procurement and facility investment move together. The alternative is a premium niche: expensive cups that make cafés feel virtuous while the waste system underneath them stays exactly as it was. Pretoria's laboratory has done its part. The system around the laboratory has not yet done its own.
What happens if compostables scale faster than composting?
If compostable packaging spreads while composting capacity stands still, the damage compounds in three places. Recycling streams absorb more PLA lookalikes and lose quality; landfills absorb more material that decays without air and gives off methane; and public trust absorbs another round of green claims that do not survive contact with a bin. The farm side of the ledger cuts the other way: the South African sugar industry supports a million livelihoods, according to Daily Maverick's reporting, and bagasse that becomes packaging feedstock is income that stays in cane country rather than ash in a field. Export markets add a third pressure, since European buyers increasingly ask for low-carbon packaging and standardised proof; the same standardisation debate visible in climate-summit negotiations and in country profiles across the Bureau's Factbook. A country that builds composting alongside its bioplastics industry gains a product it can sell abroad; a country that only builds the product gains a story it cannot dispose of.
What should change before the next cup is sold?
Watch three things. First, Petco's study of plant-based packaging penetration, which the department says will guide future policy interventions; the first hard number on how much compostable material is actually entering South African bins. Second, whether the Waste Management Flagship Programme's organic-recovery pilots and the Recycling Enterprise Support Programme's grants grow from pilots into municipal capacity, and whether separation at source becomes a habit rather than a guideline. Third, whether the CSIR's licensing of its bioplastic technology brings industrial-scale production, and with it prices closer to conventional plastic. For readers, the honest rule until then is the one the reporting already implies: check the label for industrial-composting certification, keep compostable cups out of the recycling bin, and treat any cup sold without a collection route as a promise still waiting for its system.
The three lenses
West Lens:
West: Western industry analysis treats the problem as a sorting problem first and a chemistry problem second. Rabobank's review of bioplastics notes that PET and PLA cannot be distinguished by current sorting processes, yet have different melting points, so PLA contamination damages recycled PET production; it also notes that waste systems are not set up to sort biodegradable plastics at all. Europe and the United Kingdom, in this reading, are focused on standardising and assessing benefits rather than stimulating demand, with Italy as the exception: industrial composting capacity grew alongside compostable bags and public education, and consumers there learned to tell the materials apart.
East Lens:
East: India's debate has moved further into law than South Africa's. Under amendments to India's Plastic Waste Management Rules published in 2024, a plastic may only be called biodegradable if it degrades by biological processes and leaves no microplastics behind; but, as The Hindu reported, the rules do not yet specify which tests prove the absence of microplastics, or how complete the elimination must be. Compostable plastics, in the same coverage, degrade only with industrial or large municipal waste facilities.
South Lens:
South: The Southern story is the one playing out in South African fields. The CSIR is trialling biobased, biodegradable mulch films on a pineapple farm outside Peddie in the Eastern Cape, funded through the Department of Science, Technology and Innovation's Circular Economy Demonstration Fund, with the films designed to break down fully in soil into biomass, water and carbon dioxide after the cropping cycle. The trial matters because it tests the material where it will actually be used, rather than in a laboratory composter.
The consensus
- What we agree on
- What everyone agrees on: plant-based plastics can cut fossil feedstocks, and some of them, PLA and PHA, can break down into water, biomass and carbon dioxide, but only under specific conditions that most household bins and compost heaps cannot supply.
- What we don't agree on
- Where accounts differ: South African reporting stresses the laboratory breakthrough and the missing composting network; Indian coverage stresses tighter labelling rules and the unresolved question of microplastics; Western industry analysis stresses sorting and recycling damage, and holds up Italy as the exception where capacity, bags and public education grew together.
- What we know
- What is known: an estimated 440,000 tonnes of plastic leak into South Africa's environment each year; CSIR mulch films are designed to biodegrade in soil within one to three months for short-term crops and up to 12 months for longer ones; PLA needs sustained industrial-composting heat of 58°C to 60°C; and South Africa has virtually no municipal industrial composting at scale.
- What we don't know yet
- What is not yet known: how quickly South Africa can build composting capacity, whether Petco's market study will lead to new rules on labelling and collection, whether bioplastics can close their three-to-five-times cost gap with petroleum plastics, and whether consumers will sort a lookalike material correctly at scale.
- What we expect
- What to expect: the Petco study's findings feeding into policy debate, pilot organic-recovery projects testing whether separation at source can work in practice, CSIR licensing talks for its bioplastic technology, and continued pressure on brands to prove that a green label matches a real end-of-life route.
Questions, answered
Why does my plant-based coffee cup not break down in my compost heap?
Most compostable cups are made from PLA, which needs sustained industrial composting conditions, temperatures of 58°C to 60°C, controlled humidity and active microbes, to break down into water, biomass and carbon dioxide. A home compost heap never reaches those temperatures, so the cup can sit intact for years. South African labelling under standard SANS 1728 states the industrial-composting requirement on the product itself.
What is the difference between plant-based, biodegradable and compostable plastic?
Plant-based describes the feedstock, not the fate: Bio-PET from sugar-cane ethanol is chemically identical to conventional PET and survives for centuries if littered. Biodegradable means microbes can break the material down, but the conditions and timeframe may be unspecified. Compostable is the strictest claim: the material breaks down under defined composting conditions, usually industrial, without toxic residues.
Why is putting a compostable cup in the recycling bin harmful?
Clear PLA looks identical to conventional PET, so it slips into recycling batches, but it melts at a lower temperature and chars during processing. That charring degrades the structural integrity of the recycled PET, damaging the clean streams that South Africa's recycling network depends on. The environment department therefore insists on separation at source and accurate sorting before compostables can scale safely.
What is South Africa doing about the missing composting capacity?
The Department of Forestry, Fisheries and the Environment points to its 2018 guidelines on separating waste at source, a Waste Management Flagship Programme piloting organic recovery with the International Finance Corporation and the Development Bank of Southern Africa, and grants of up to R5-million for emerging waste ventures. Producer responsibility organisation Petco is also studying market penetration to guide future policy, but no national composting network exists yet.
Sources
- Daily Maverick (Oct 27, 2026)