Published 6 months ago.
About a 7 minute read.
Image: Plastic-backed foils such as API's could go on to become components of life-saving pharmaceuticals | API Foilmakers
Savvy scientists from Scotland and Singapore have developed sustainable ways to breathe new life into vegetable and plastic waste, as well as local manufacturing.
Reshma Beauty is one of many personal-care brands that uses kale in its products | Image credit: Reshma Beauty
Scientists from Nanyang Technological University, Singapore (NTU Singapore)
have developed a technique to convert kale waste for use in health and personal
care products, reducing food waste and emissions.
Millions of tonnes of food and vegetables are discarded globally every year. In
the case of leafy vegetables such as kale and lettuce, farmers cut off outer
as they are harvested in order to sell perfectly sized and aesthetically
pleasing vegetables with no signs of damage or yellowing. This commercial
practice results in a significant amount of perfectly good, edible leaves being
thrown away. In Singapore alone, some 817,000 tonnes of food waste were
generated in 2021 — almost half of which was fruit and vegetables.
Phytochemicals found in plants are known to prevent damage to cells in the body
and are widely used in health and personal-care products — including nutritional
supplements such as antioxidants and lutein; as well as face scrubs and shampoo
with kale extracts.
Current processes for extracting phytochemicals from kale are energy-intensive,
requiring high pressure and temperatures, which contribute additional CO2
emissions to the environment. Moreover, industrial extraction processes only
target a single type of phytochemical each time.
Seeking a more sustainable and efficient method to turn vegetable waste into
“treasure,” the NTU researchers looked to naturally derived natural deep
eutectic solvents (NADES) — non-toxic liquids made up of plant-based
compounds such as amino acid, sugar and vegetable oil by-product — for answers.
While NADES have long been studied in separation technology for food and
pharmaceutical industries, not much is known about their ability to extract
different classes of bioactive compounds from vegetable waste.
Focusing on bioactive compounds in kale, the NTU research team explored a range
of NADES — mixing them with processed kale waste to observe how molecules
reacted to each other.
After repeated testing, the researchers established the best NADES solvent for
optimal extraction of bioactive compounds. The NTU team found that when the kale
waste and NADES mixture is stirred and set aside, it naturally separated into
layers — facilitating the easy extraction of the phytochemicals from kale
(polyphenols, carotenoids and chlorophylls) without the need for heating.
Since there is no need to heat or pre-treat the kale waste — for example, by
freeze drying — the costs, as well as the emissions, of the simpler extraction
process are kept down. The NTU research team is confident their new method would
be scalable and attractive, cost-wise, to the industry.
“The use of non-toxic and naturally derived solvents in our method makes it a
food-safe technique,” said Hu
Xiao, Professor at the NTU
School of Materials Science and Engineering, Program Director of Sustainable
Chemistry & Materials at Nanyang Environment & Water Research Institute,
and lead author of the study. “At the same time, our method preserves the
potency of the extracted active ingredients — making it highly attractive for
industry adoption. The extracted nutrients can potentially be used for
applications in personal-care products, cosmetics, food supplements and herbal
The NTU research team said that their waste-to-resource approach tackles both
food waste and carbon emissions, supporting the development of a zero-waste,
published in the scientific journal Separation and Purification Technology
in July, is aligned with the research pillar of NTU
2025 — the
University’s five-year strategic plan which aims to leverage innovative research
to mitigate human impact on the environment.
The NTU team has filed a patent in Singapore for its non-toxic, high-yield
extraction technique (learn more about it
here). For their next
steps, the researchers are investigating the feasibility of applying their newly
developed method to extract beneficial compounds from other types of fruits,
vegetables and medicinal plants such as dragon fruit, spinach and lettuce.
Kale waste for the study was provided by Sustenir Agriculture, a
Singapore-based, high-tech urban-farming company. The kale leaves used for the
research did not meet commercial quality standards and were intended to be
discarded as waste.
API Foilmakers produces labels for a wide range of consumer products, including Johnnie Walker Scotch Whisky | Image credit: API Foilmakers
Meanwhile, a team of Scottish researchers is exploring what is believed to be a
world first: a new process that could see plastic waste from industrial
processes become pharmaceuticals for neurological conditions.
Scientists from Impact Solutions,
biotechnology researchers from the University of
Edinburgh, packaging manufacturer API
Foilmakers, and the Industrial Biotechnology
Innovation Centre (IBioIC) are exploring the
feasibility of a new
to recycling polyethylene terephthalate (PET) — a type of plastic
commonly used in the production of food and drink packaging.
The project represents the first time scientists have explored the use of PET as
a starting point for manufacturing medication. Using genetically modified
bacteria and enzymes to break down the plastic waste, the core chemical
components can then be converted into valuable pharmaceuticals for treating a
range of life-limiting conditions such as brain disorders.
API Foilmakers, which is providing the input material, specializes in rolls of
plastic-backed foil for a variety of
commercial packaging applications; it produces enough to stretch approximately
18 kilometers each month, creating up to 100 tonnes of PET waste. The printing
method also means that one small error can render an entire roll unusable.
While other companies have been known to use enzymes to breakdown
this can often produce lower-quality plastic — which still languish in landfill
in the long term.
As most pharmaceuticals are still petrochemical-based, and with
medicines mostly manufactured overseas, the project represents an opportunity to
develop more sustainable techniques.
“We are thrilled to be leading on this exciting project, which could have a
major influence in the way we produce pharmaceuticals here in the UK,” said
Development manager at Impact Solutions. “By exploring the use of PET as part of
the manufacturing method, we are not only addressing the environmental
challenges posed by plastic waste but also creating a sustainable approach for
producing essential medicines. At the moment, we are working towards a
small-scale proof of concept — laying the foundation for the future
commercialization of this technology. Of course, discussions around regulation
and trials will come further down the line as we prove the capabilities of this
process at scale.”
The researchers are also exploring the various paths from PET to other forms of
medication, supporting the UK government’s Life Sciences
create a globally competitive environment for life-sciences manufacturing in the
UK — building resilience in response to international disruption and shortages
experienced during the pandemic.
“There’s potential for this to be a turning point for the pharmaceutical
sector,” said Dr Stephen
Wallace, UKRI Future
Leaders Fellow and senior lecturer in biotechnology at University of
Edinburgh. “While this project is focused on a specific type of plastic waste
from the foil rolls, it’s a platform technology that could in the future be
applied to alternative forms of waste PET from other sectors — if we get the
foundations right. We’ve already had some promising talks with big pharma
companies keen to explore this new approach.”
Published Aug 17, 2023 8am EDT / 5am PDT / 1pm BST / 2pm CEST