Biomaterial bonanza: putting plastics out of a job

With the rapidly approaching midwinter (at least for the Northern Hemisphere) festival - and traditionally a time of gift-giving - wouldn't it be great to say that humanity can offer a present to the entire planet? The amount of plastic-based products manufactured every year is somewhere between three hundred and four hundred million tons, about fifty percent of which is single-use or disposable. 

Presumably if you've got any sort of interest whatsoever in the world around you (and how your children will get on) then you have been replacing disposable plastic items with reusable non-plastic, or at least biodegradable, alternatives. But are the companies producing the latter guilty of subtle greenwashing?

A friend recently told me that he had put some allegedly biodegradable plastic bags into his compost heap, only to retrieve them - albeit with some holes in - a year or so later. Bearing in mind there isn't an internationally-recognised set of characteristics for just what defines biodegradable, is it surprising that the wool (sorry, polyester) is being pulled over consumers' eyes?

A report last year summarised a three-year research programme at the UK's University of Plymouth, offering clear evidence that many types of allegedly biodegradable bags do not break down when buried in soil or underwater. Although the material did decay in open air, it was just into smaller pieces of plastic rather than degrading into simpler molecules. 

Recent studies by Tel Aviv University and the Goethe Universität in Frankfurt go even further in putting allegedly ecofriendly materials in a bad light. Both claim that not just biodegradable plastics but even those based on starch and cellulose contain numerous toxic chemicals. Such materials are used in food and drink packaging. So where do we go from here?

Last year I wrote a post about the potential of chitosan, a genuinely biodegradable material made from marine arthropod carapaces (i.e. shellfish discards) that can be produced in an eco-friendly process. 

There now appear to be several other materials that also have the possibility to replace traditional plastics. A group at the University Of Science And Technology Of China have developed a lightweight but durable material using mica and cellulose-derived nanofibre that has more than double the strength of high-performance petroleum-based plastics.

Another alternative to plastic that utilises surprising source material has been developed by a student at the University of Sussex in the UK. Lucy Hughes has used red algae to augment discarded fish scales and fish skin to produce a single-use translucent substance called MarinaTex. In addition to its use of material otherwise destined for landfill, MarinaTex - which biodegrades within six weeks - is the antithesis of conventional plastics in that the red algae component makes its production carbon positive! 

The bad news is that both materials are still at the research and development stage and there is no indication of when they would be ready for commercial mass-production. Crucially, there doesn't appear to be any news of large corporations buying the research for implementation; why is it that so many paradigm-shifting projects are having to be developed by crowd-funded start-ups rather than established multi-nationals? 

Surely there are enough ethical executives out there to pick up once the research has shown such potential? But as I've no doubt mentioned before, we are living in a world where the largest national economy - the United States of course - spends more each year on pet grooming products than on nuclear fusion research. Will future historians dub our era the Decades of Dubious Sanity?

Meanwhile, immense amounts of plastics are dumped in landfill and the oceans, polluting everything, including microplastics in the food we eat. Isn't it time these researchers are given the backing they need to convert smart ideas into ecosystem saviours? After all, no-one, no matter how wealthy, can opt out of the planetary biosphere!

Ocean acidification: climate change at the sour end

A few weeks ago, I overheard a 58 year old man telling a 12 year old boy that the most dire of scientists' warnings concerning global warming over the past 30 years had failed to materialise - and that what the boy needed to learn was to be able to separate facts from propaganda.

Although it is no doubt next to impossible to be able to change such entrenched mindsets as those of this particular baby boomer, there is still extremely limited public understanding of the insidious changes currently taking place in our oceans. In addition to the rise in both sea temperature and sea level (approaching a centimetre every two-to-three years) a rapid increase in ocean acidity is now on course to profoundly disrupt marine life.

With the USA pulling out of the Paris Agreement, will the rest of world manage to pull together in order to prevent another tipping point? After all, increasing ocean acidification isn't something us non-marine scientists can directly observe. One key point that is immediately obvious is that it isn't a localised issue: as a third of atmospheric carbon dioxide is absorbed into the oceans, all the planet's seas will be affected. The decrease of 0.1pH unit in the past few centuries equates to an astonishing 26-29% increase in acidity. What's more, this change is predicted to have doubled by the end of this century. Clearly, the effect on marine life is set to be substantial.

So what is being done to assess the probable issues? Various projects around the world are using mesocosms - transparent cylinders up to ten metres long - to understand the effects of current and predicted near-future acidity levels on marine life. Coral bleaching is possibly the one condition people will have heard of (although there appear to be an astonishing number of people who think that coral is a plant rather than invertebrate animal) but sea temperature changes are as much a cause as increased acidity. Apart from causing stress to some marine organisms, leading to such conditions as lowered immune systems and so the spread of disease, acidification reduces the material available for shell and carapace formation, especially for juveniles and nauplii.

The problem isn't so much the change itself as the rate of change, which is far faster than normal geophysical processes. Indeed, one report states that over the past 20 million years, changes in oceanic acidification have been barely one percent of the current rate. Obviously, there is minimal chance of the non-directed mechanism of natural selection keeping pace with adaptations to the new conditions.

While many organisms will suffer, some such as jellyfish and toxic algae may benefit, with the latter leading to the poisoning of key fishing industry species. This in turn could lead to toxins entering the human food chain, on top of the economic issues from the decline in fish and shellfish stocks. Indeed, the US Pacific coast aquaculture industry is already experiencing a reduction in the shellfish populations. This will be in addition to the pollution of fresh waterways already explored in a post last year.

Of the various experiments aiming to understand the impact of the rapid increase, the largest project is the pan-European Biological Impacts of Ocean Acidification (BIOACID) scheme. Giant mesocosms sunk in a Swedish fjord have been sealed with local ocean water (and associated organisms) and half of them modified with the projected pH level.

Similar but small projects are underway in New Zealand and the Canary Islands, with preservation of edible stocks a key priority. Another problem with a decline in shellfish species destined for human consumption would be the loss of the raw material for chitosan, which may prove to be an ecologically-friendly replacement for plastic packaging.

Clearly, there could be numerous - and some as yet unknown - knock-on effects from the ocean acidification. Unlike the rise in atmospheric temperature, it is much more difficult to see the results of this fundamental change and for the public to understand the consequences. Yet again, the life forms affected are far from the cute poster species usually paraded to jump-start the public's environmental consciousness. Unfortunately, these may prove to be far more critical to the future of humanity and the wider world than say, giant pandas or Amur leopards. It's time for some serious sci-comm to spread the warning message!

Saving the oceans with chitosan: are prawns the new plastic?

Earlier in the year, I wrote a post concerning a new, extremely strong, material derived from limpet teeth. Bearing in mind our current reliance on oil-derived materials, another form of marine life may hold the key to the global plastic pollution crisis.

Every year over six million tons of crab, lobster and shrimp is processed as seafood. This industry's by-products include the chitin-rich carapaces of all these creatures. Chitin is a substance found in fungi and invertebrates, with a range of uses from making paper to food processing and biotech to water treatment. In the past five years, research has been gaining momentum for another use for chitin which may prove to be a game changer (and for once, this hyperbole could well prove an understatement).

Currently about 335 million tons of plastics are produced annually, of which one-third is for single (and therefore disposable) use. Only about twenty percent of the total is recycled. We have all seen news items about the Great Pacific Garbage Patch and the large numbers of wildlife species affected by ingesting such material. We are now also beginning to understand that we humans too are ingesting microplastic particles that contaminate our food chains, to the tune of forty to fifty thousand particles per person per year. Quite apart from the plastic itself, the unwanted materials in our food may contain absorbed chemicals and heavy metals known to be toxic. And that's separate to all the microplastic that rains down on us and our food from practically every manmade structure we enter.

In 2014 a biodegradable polymer was developed from chitosan, a material made by subjecting the chitinous carapaces of marine arthropods, primarily crustaceans, to a range of treatments. Chitosan has been in use for some decades in diverse fields such as medicine, as a biopesticide and as a filtration and clarification material. However, the acids used to produce it have markedly affected its green credentials. Over the past five years a rather more ecologically-friendly set of processing techniques, including ultrasonics and microwaves, have been developed. The upshot of this means that chitosan could eventuate into one of the most ubiquitous materials on the planet. Pioneering companies have been set up around the world to convert chitosan into biodegradable packaging.

One such corporation is the Scottish-based CuanTec, who are developing food packaging that is antimicrobial while also being compostable. They claim to be the first company able to use bacterial fermentation to extract chitin from langoustine shells on an industrial scale, which is subsequently processed into chitosan. The antimicrobial properties of the packaging means that the foodstuffs it contains will have a longer - possibly even doubled - shelf life, with protection against the likes of Salmonella, Listeria and E. coli.

The first three types of packaging are said to be a food film wrap, single-use milk bottles and beer can collators (the latter incidentally for a company who produce their alcohol from stale bread rolls!) However, to date CuanTec has sought crowd-funding in order to begin commercial operations, which seems astonishing. Their products are predicted to cost slightly more than the petro-chemical alternatives, but hopefully industry will realise that the advantages far outweigh this.

Across the Atlantic from CuanTec other companies are climbing on a similar bandwagon. Mari Signum in Virginia, USA, is utilising an ionised liquid (including vinegar) technique to extract chitin for the development of various products, including 3D-printed alternatives to plastic packaging. As a recognition of their efforts, last year the U.S. Environmental Protection Agency presented them with their Green Chemistry Challenge Award. They're not the only American company to investigate the potential of swapping plastics with chitosan: the California-based CruzFoam have expanded their research from chitin-derived surfboard cores to packaging aimed to replace polyurethane foam.

Universities in various nations are also working with chitin to produce bioplastics that combine with other materials such as cellulose. The National University of Singapore has combined grapefruit seed extract with chitosan to produce a composite film for use a food packaging which can extend the shelf life of perishables such as bread. In a nation as humid as Singapore, you can clearly see the savings to the consumer if such materials become commercially available - assuming the affected food producers don't buy up and block the relevant patents, that is!

Clearly, chitosan looks like a material whose time has come. Apart from the potentially vast reduction in plastics, the widespread use of chitosan-derived food packaging would likely lead to much less food being thrown away because it has spoiled. It's unlikely that chitosan manufacturers would run out of their raw material either, since chitin is the planet's second most abundant biopolymer - climate change effects on marine crustaceans not withstanding. I can't help but ponder just how many more natural substances are waiting their turn to be the next wonder material?