Editor’s Comment

The final frontier

Could astronauts be about to turn their urine into 3D printed polymers ?

I have never been one to shy away from the unusual stories or to be afraid of getting my hands dirty, and so a news release originating from the London-based Institution of Mechanical Engineers recently left a definite mark on my desk.

First the headline, and if you’re reading this whilst eating your lunch, you might want to put down your sandwich, salad or sushi for a minute. Apparently scientists want to make plastics in space from recycled human waste.

Steven Pacitti

Affectionately referred to as ‘atom economy’ by assistant professor at Clemson University, South Carolina (USA), Dr Mark Blenner, the concept centres on the need to find ways of reusing and recycling everything (and I mean everything!) that astronauts bring with them on journeys that might span several years.

Clemson University is therefore working on ways of repurposing waste molecules from breathing, eating and, well, other bodily functions, and converting them into products including polyesters and nutrients. It is claimed that genetically-engineered yeast, which feeds on nitrogen (obtained from urine) and carbon (from carbon dioxide in exhaled breath), can be used to manufacture monomers that are then linked to make polymers. These could in turn be used in a 3D printer to generate plastics parts.

Whilst this may well be possible, we are talking small volumes of material at the moment and scientists will need to ramp this capacity up to make it a worthwhile pursuit.

Indeed, the production of plastics using organisms is well known but the idea of a ‘bacterial biofactory’ in space is enough to make the mind boggle. Of course, the idea of using waste as feedstock is the ultimate circular economy, or ‘closed loop’, so where better to develop future science than hundreds of miles above our heads?

It is uncertain if human excrement is included in this repurposing exercise, but if you’ve ever wondered what happens to it in orbit then the answer is that it is simply ejected into space where it burns up in the Earth’s atmosphere. I know you wanted to know that.

Children are excited to see their favourite products through the packaging

This all sounded vaguely familiar to me when I read it, and that’s because we ran a news story about this very research project back in August 2015, and at the time it was reported to be a three-year study. The reason for its reappearance in the news now is that Dr Blenner presented his team’s findings up to now at the recent National Meeting and Exposition of the American Chemical Society in Washington, USA.

He explained that the biological system being developed includes a variety of strains of the yeast yarrowia lipolytica, which require nitrogen and carbon to grow. In order to use the carbon dioxide from exhaled breath, the yeast requires a middleman to ‘fix’ the carbon into a form they can ingest. Dr Blenner explained that the yeast relies on algae provided by the researchers.

He told me that his team has demonstrated the basic principle of making PHAs in yarrowia lipolytica and are currently up to around 300mg/L.

“We still need to increase this as well as the percentage of PHA accumulation. We haven’t produced enough PHA to test yet, and we are starting work to control the composition through metabolic engineering. We’ve used urine and cell biomass to grow these yeast,” he explained.

While astronauts may be about to turn their urine into 3D printed polymers that can produce tools such as spanners, Blenner’s yeast could also find applications here on Earth. For example, DuPont is already using yeast to make acids for aquaculture, but the yeast feeds on refined sugar instead of waste products.

Two other research teams are reported to be engineering yeast to make polyesters, but Blenner says that they are not engineering the organisms to optimise the type of polyester produced. And the yeast used? It is the yeast used to make beer, so beer enthusiasts might well be interested in further research in this area.

A recent report by research company Mintel claims that almost 40 per cent of consumers in the US would choose a product over a competitor purely because the packaging allows them to see the product inside.

It comes at a time when companies such as Sonoco have been busy developing and launching flexible packaging with clear windows for products such as snacks, cookies and crackers. Providing transparent packaging while still protecting freshness is a real challenge for converters but Sonoco’s ClearGuard is one example of a solution, providing low oxygen and water vapour transmission rates.

And if further consumer research is required, my three-year-old daughter Aria inadvertently did just that recently. As I was sat at my desk at home working, she ran over to me enthusiastically exclaiming: “Daddy, look, I can see the fruit in my fruit pouch!”

She was fascinated to see that her Cow & Gate Fruit Mix (other similar products are available) pouch was no longer opaque but now transparent. Gone was the aluminium and in its place a clear window in the side of the flexible pack.

I asked Stefano Tamarindo, R&D manager at Italy’s Gualapack, which manufactured the pouch, for more information. Tamarindo explained that the company replaced the aluminium foil with a transparent plastics coated layer, which gives the same properties of aluminium. He would not be drawn on the actual materials used for confidentiality reasons.

But, as a result of the change, the shelf-life and taste of the product remains the same as before and, as Tamarindo continued, “our lovely consumers and their parents can see what’s inside”.

let me know what you think