Seaweed – a Natural Solution to Keep Banknotes Clean

COVID-19 has impacted cash usage in a number of ways. Some were inevitable, such as a reduction in use due to the move to online shopping and lockdowns. But one was avoidable and has unfairly and negatively affected both the use and perception of cash, and that was that it carried, and was capable of transmitting, the coronavirus.

This misinformation has been well covered in previous issues of Currency News™, but suffice to say some damage has been done from which cash usage may never fully recover.

When this attack on cash occurred, Currency News published a supplement to clarify the situation at that time, albeit that much of its content remains relevant.

One aspect the research for the COVID-19 supplement did bring to the fore was that banknotes can and do carry pathogens (infectious agents) such as bacteria and viruses. But so do other items that we touch and use every day. And there are ways in which banknotes can be treated to eliminate, or greatly reduce, the amount of such agents.

In that supplement, we described a new development by Inovink, a specialist in additive ink materials for banknotes, called BioNote®. It was described as a novel microbial control material which can be added to all types of protective varnish coatings used in banknote printing. It can also be added to paper during the manufacturing stage or to polymer substrates during the opacification process.

Inovink worked with Penrhos Bio, a newly created joint venture between Unilever and Innova Partnerships, which has now published details of the science behind this development.

The magic ingredient is an organic compound called Lactam, which puts a halt to the spread of bacterial contamination by stopping it growing in the first place. The inspiration for this breakthrough and research comes from a natural source, seaweed.

Seaweed’s natural cleaning power

Scientists have discovered that a species of seaweed, Delisia Pulchra, has a natural chemical defence mechanism that protects it from bacterial contamination. It does this by disrupting the bacteria’s communication systems, which stops them from communicating with each other and forming biofilms (a collection of microorganisms that grow on many surfaces), which they then use to spread and grow.

According to Unilever’s R&D Programme Director of Biotechnology and Biosourcing, Dr Neil Parry, ‘in dirty waters, seaweed biology blocks the communication between bacteria so that it cannot colonise and build up on healthy surfaces of the plant.

Now, after ten years of extensive research into this biological superpower, we have successfully replicated this in the lab as Lactam, an organic compound developed from natural chemicals in seaweed’.

Lactam is biodegradable, and just like its ocean counterpart, it has the ability to control potential contamination using signalling methods used in nature. But what is exciting about Lactam is that as well as stopping bacteria growing biofilms, it also works on fungi, yeast and algae. And it’s this development that pushes Lactam’s potential beyond household and human cleaning products and into a myriad of other sectors.

All everyday items, to a greater or lesser extent, are subject to bacterial contamination, as are people – more that 80% of bacterial infections in humans are estimated to involve the formation of biofilms. Consequently, Lactam has the potential to tackle some of the biggest societal and environmental challenges where microbial biofilms are commonplace – including banknotes.

Lucky coincidence

Inovink has been working with Unilever (and now Penrhos Bio) for the past four years to develop BioNote, its launch at the outbreak of the coronavirus being a ‘lucky’ coincidence.

In tests, both polymer and paper banknote substrates were printed with varnish containing varying concentrations of Lactam. Printability and appearance were not affected by its presence and subsequent independent laboratory tests (crumpling, abrasion etc.) proved that the inherent protective benefits of the banknote varnish were not diminished by its inclusion.

Proof of the success of the additive was also obtained by submitting banknote samples to an independent microbiology research organisation, which carried out biofilm efficacy testing using an extensive library of biofilm forming species.

Whilst Penrhos Bio is exploring applications in household cleaning and also dental products, Inovink has an exclusive global license for the technology for banknotes.

Very small quantities (parts per million) of the colourless, non-toxic material are required to be effective on banknotes. BioNote does not affect the colour of banknote substrates or the opacity of overcoat varnishes, be they water, solvent based or UV curable varnishes, says Inovink. The material can be mixed into the protective varnish at the banknote printworks or can be added at the varnish manufacturers’ premises. Implementing BioNote in the substrate would be done at the substrate manufacturers’ mill.

According to Inovink, BioNote can be added at any part of the supply chain and therefore central banks and banknote printers do not need to change their current suppliers, or for that matter, the design of a current banknote series.

BioNote is available to central banks, banknote printers and suppliers. In addition to working directly with central banks, Inovink will partner with banknote printers and also substrate and varnish manufacturers who may wish to specify BioNote using their own branding.

David Bedford, Managing Director of Inovink said: ‘of course we readily accept the statement from the WHO and the findings from studies by the ECB and the Bank of England that banknotes in their current form carry very little risk of transmitting diseases. The application of BioNote should be seen as a complementary and environmentally friendly way of keeping banknotes cleaner for longer while also maintaining the public’s confidence in banknotes.’