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?

Concrete: a material of construction & destruction - and how to fix it

How often is it that we fail to consider what is under our noses? One of the most ubiquitous of man-made artifices - at least to the 55% of us who live in urban environments - is concrete. Our high-rise cities and power stations, farmyard siloes and hydroelectric dams wouldn't exist without it. As it is, global concrete consumption has quadrupled over the past quarter century, making it second only to water in terms of humanity's most-consumed substance. Unfortunately, it is also one of most environmentally-unfriendly materials on the planet.

Apart from what you might consider to be the aesthetic crimes of the bland, cookie-cutter approach to International Modernist architecture, there is a far greater issue due to the environmental degradation caused by the concrete manufacturing process. Cement is a key component of the material, but generates around 8% of all carbon dioxide emissions worldwide. As such, there needs to be a 20% reduction over the next ten years in order to fulfil the Paris Agreement - yet there is thought there may be a 25% increase in demand for concrete during this time span, particularly from the developing world. Although lower-carbon cements are being developed, concrete production causes other environmental issues as well. In particular, sand and gravel extraction is bad for the local ecology, including catastrophic damage to the sea bed.

So are there any alternatives? Since the 1990's, television series such as Grand Designs have presented British, New Zealand and Australian-based projects for (at times) extremely sustainable houses made from materials such as shipping containers, driftwood, straw bales, even shredded newspaper. However, these are mostly the unique dream builds of entrepreneurs, visionaries and let's face it, latter-day hippies. The techniques used might be suitable for domestic architecture, but they are impractical at a larger scale.

The US firm bioMASON studied coral in order to develop an alternative to conventional bricks, which generate large amounts of greenhouse gases during the firing process. They use a biomineralisation process, which basically consists of injecting microbes into nutrient-rich water containing sand and watching the rod-shaped bacteria grow into bricks over three to five days.  It's still comparatively early days for the technology, so meanwhile, what about applying the three environmental ‘Rs' of Reduce, Reuse and Recycle to conventional concrete design and manufacturing?

1 Reduce

3D printers are starting to be used in the construction industry to fabricate building and structural components, even small footbridges. Concrete extrusion designs require less material than is required by conventional timber moulds - not to mention removing the need for the timber itself. One common technique is to build up shapes such as walls from thin, stacked, layers. The technology is time-effective too: walls can be built up at a rate of several metres per hour, which may induce companies to make the initial outlay for the printing machinery.

As an example of the low cost, a 35 square metre demonstration house was built in Austin, Texas, last year at a cost of US$10,000 - and it only took 2 days to build. This year may see an entire housing project built in the Netherlands using 3D-printed concrete. Another technique has been pioneered at Exeter University in the UK, using graphene as an additive to reduce the amount of concrete required. This greatly increases both the water resistance and strength compared to the conventional material, thus halving the material requirement.

2 Reuse

Less than a third of the material from conventionally-built brick and timber structures can be reused after demolition. The post-war construction industry has continually reduced the quality of the building material it uses, especially in the residential sector; think of pre-fabricated roof trusses, made of new growth, comparatively unseasoned timber and held together by perforated connector plates. The intended lifespan of such structures could be as little as sixty years, with some integrated components such as roofing failing much sooner.

Compare this to Roman structures such as aqueducts and the Pantheon (the latter still being the world's largest unreinforced concrete dome) which are sound after two millennia, thanks to their volcanic ash-rich material and sophisticated engineering. Surely it makes sense to use concrete to construct long-lasting structures, rather than buildings that will not last as long as their architects? If the reuse of contemporary construction materials is minimal (about as far removed as you can get from the traditional approach of robbing out stone-based structures in their entirety) then longevity is the most logical alternative.

3 Recycle

It is becoming possible to both recycle other waste into concrete-based building materials and use concrete itself as a secure storage for greenhouse gases. A Canadian company called CarbonCure has developed a technique for permanently sequestering carbon dioxide in their concrete by converting it into a mineral during the manufacturing process, with the added benefits of increasing the strength of the material while reducing the amount of cement required.

As for recycling waste material as an ingredient, companies around the world have been developing light-weight concrete incorporating mixed plastic waste, the latter comprising anywhere from 10% to 60% of the volume, particularly with the addition of high density polyethylene.

For example New Zealand company Enviroplaz can use unsorted, unwashed plastic packaging to produce Plazrok, a polymer aggregate for creating a concrete which is up to 40% lighter than standard material. In addition, the same company has an alternative to metal and fibreglass panels in the form of Plaztuff, a fully recyclable, non-corroding material which is one-seventh the weight of steel. It has even been used to build boats as well as land-based items such as skips and playground furniture.

Therefore what might appear to be an intractable problem appears to have a variety of overlapping solutions that allow sustainable development in the building and civil engineering sector. It is somewhat unfortunate then that the conservative nature of these industries has until recently stalled progress in replacing a massive pollutant with much more environmentally sound alternatives. Clearly, green architecture doesn't have to be the sole prerogative of the driftwood dreamers; young entrepreneurs around the world are seizing the opportunity to create alternatives to the destructive effects of construction.

The great outdoors: getting children back to nature

With Christmas just around the corner it seems like a good time to look at the benefits of persuading children to swap their hi-tech electronic gadgets for the wonders of the great outdoors. The recently-slated Toys 'R' Us television advert that promotes their plastic junk at the expensive of a 'dull and boring' nature field trip only highlights a trend that as the rural population decreases, natural phenomena such as animals, weather and good, clean soil are deemed solely of interest to farmers. Some years ago, a London acquaintance who teaches English at a senior school reported that during a woodland walk - to explore nature poetry rather than nature itself - several of her female teenage students cried due to getting mud on their shoes. Just how distanced are children becoming from the world beyond their front door!

A sense of scale: humans against California redwoods

The last few decades have seen a move away from the outdoor adventures that typified my childhood: catching butterflies; building woodland dens; even exploring a derelict house. Instead, sitting in front of computers, TVs and games consoles has become prevalent, sometimes all at once. Not that this has gone unnoticed, as discussed in Richard Louv's best-selling Last Child in the Woods: Saving Our Children From Nature-Deficit Disorder. Although the phenomenon is common across the developed world, some countries fare better than others. For example, recent reports suggest New Zealand children (feeling a bit smug at this point) spend rather more time outdoors than their Australian, American or British counterparts. However, I'm sure there's room for improvement just about everywhere. There are many reasons behind the stay-at-home trend in addition to the obvious delights of being cosily tucked up with digital devices, but I believe it is more important to explore the effects this is having on our children:

1. The most obvious problem caused by a shortage of physical activity outdoors - which after all is free, compared to the indoor play centres often used for children's parties - is the lack of opportunity to develop coordination and motor skills beyond the mouse or joystick. Since we've experienced a generation-on-generation increase in the number of calories, sugar and fat in our diet, then clearly there should also be an increased amount of time spent burning this off. Obviously this hasn't happened, and various groups such as the International Association for the Study of Obesity have tracked the post-war growth in overweight children. If you haven't seen any of the resulting graphs, they make for troubled reading...
2. But it isn't just physical health that is affected. As a species, we are still coming to terms with urban living and the psychological problems of existence in near-identical cuboids in residential estates frequently bereft of greenery. The World Health Organization's definition of health includes mental well-being, which can incorporate the notion that regular playing outdoors confers benefits on children. I don't consider this as just referring to strenuous exercise: exploring the randomness of nature - from building sand castles to snowball fights - as well as the simple joys of experiencing weather at first hand, are also important. As if to confirm the problems that a lack of balance in indoor/outdoor activities can lead to, a work colleague recently informed me that his twenty-year-old son, a business degree student, was reduced to tears when he was unable to log on to his online gaming account for a few days. Oh, for an adequate sense of perspective!
3. Does the changing emphasis from natural to man-made environments mean are we losing a vital part of our humanity? Or are we seeing a new form of evolution for our species? The differences between nature and artifice are profound, from the seemingly (although only from our viewpoint) haphazardness of the former to the non-messy convenience sought as a given via the latter. Even a basic understanding of processes from food at its source might be useful as an educative tool to engender empathy for a planet we are so rapidly despoiling. It's very easy for children to overlook the natural wonders that still exist in even the most densely populated of nations when they primarily associate the rural environment with the exotic non-developed locales usually favoured by natural history documentary programme makers.
   
   Viewing nature at second hand is no substitute for - literally - getting your fingers dirty, whether it is planting flowers or foodstuffs, or simply scrabbling over muddy terrain. A 2010 survey conducted in the UK indicated that between one quarter and one half of British children lack basic knowledge concerning familiar native and introduced species such as horse chestnut trees and grey squirrels. Not that I'm convinced an appreciation of the facts might lead to more environmental awareness; after all, how many times has the 'closer to nature' sustainability of pre-industrial societies been shown to be a myth? But considering for example the enormous amount of bought food that is thrown away uneaten (perhaps reaching over 40% in the USA) surely any understanding of the complex cycles within the far from limitless ecosystem may engender some changes in attitude towards reduce, reuse and recycle? As evolutionary biologist Stephen Jay Gould once said, we will not fight to save what we do not love.
4. Further to the last point, knowledge as a safety net might come in handy, should the need arise. There's an old adage that even the most 'civilised' of societies is only nine missed meals away from anarchy, as the citizens of New Orleans learnt all too well in the wake of Hurricane Katrina in 2005. Considering just how much food manufacturers rely on oil for everything from transport to packaging (did you know North Sea prawns are flown on a 12,000 mile round trip to be cleaned and de-shelled?) it doesn't just have to be a natural disaster to generate such chaos. In October 2011 a leak in the Maui gas pipeline here in New Zealand led for a few days to empty bread shelves nationwide, highlighting the fragility of our infrastructure.
   
   A 2008 UK report concluded that British food retailers would exhaust their stocks in just three days in the event of a Hurricane Katrina-scale emergency, thus suggesting that those who follow chef and forager Hugh Fearnley-Whittingstall or adventurer/survivalist Bear Grylls will be the victors. I'm not suggesting children should be taught to distinguish edible from poisonous fungi but considering the potential dangers of even cultivated food crops (did you know that potatoes turning green may be a sign of the poison solanine?) any knowledge of foraging and food preparation may prove useful as well as fun.
5. Encouraging children to explore outside is as good a method as any to beget a new generation of biologists, ecologists and their ilk. Ironically, Toys 'R' Us list over 370 items in the science and discovery section of their online catalogue. Indeed, their advert includes several seconds' footage of a boy looking through the eyepiece of small reflecting telescope labelled 'science', although judging by the angle the telescope is pointing into the ground! As I've explored previously, doing practical science seems to be a far better way to introduce young children to the discipline than mere passive viewing or reading. It can also demonstrate that - with several exceptions such as high-energy physics - many of the basic structures of scientific procedure and knowledge are well within the grasp of non-scientists (perceptions are hard to shift: I recently heard a law graduate declare she wasn't sure she would be able to understand this blog, as science is of course 'very difficult'! )
   
   Each one of the above alone would be reason enough to encourage children to spend more time outside, but taken together they suggest that there is likely to be severe repercussions across many aspects of society if the adults of tomorrow don't get enough fresh air today. It may sound like something out of a Boys' Own Journal from the era of the British Empire, but there's something to be said for the simpler pleasures in life. I know I'd rather go for a forest walk or rock pooling than play Grand Theft Auto 5 any day...

How green is my alley? Reduce, reuse & recycle

British artist Richard Hamilton's 1957 definition of pop art included the terms 'transient', 'expendable', 'mass-produced', and 'Big Business'. We've come a long way since similar contemporary cultural attitudes led to throwaway clothing and disposable furniture, but there's still plenty that needs to be done before we achieve anything approaching sustainable development. The recent news articles showing that like the Pacific, the North Atlantic Ocean has its own enormous patch of floating plastic waste, clearly define a multinational problem: but what can the average Briton do to help the environment?

The three green 'R's of reduce, reuse and recycle involve a lot of statistics published by a variety of concerns, ranging from manufacturers to environmental groups. Going with the old saying that there are lies, damn lies and you-know-what, how can the public find a way through the minefield? As an example, estimates for the UK's annual waste total vary from 100 million to 400 million tonnes - although even the lower figure is more than enough! In recent years there have been several scandals involving potentially dangerous waste collected by local councils for recycling, only to be sent to developing countries where it is picked over by scavengers. Clearly, in some cases, out of sight is also out of mind.

Perhaps this shouldn't be too surprising considering how quickly we've had to adopt ecologically-motivated measures, but another concern is the enormous regional variation in recycling collection, waste processing and recovery. Lack of processing plants and a deficiency of recycling knowledge within councils supply yet another example of the postcode lottery. In response to this some local communities are taking matters into their own hands, such as the Somerset village of Chew Magna, where the inhabitants are attempting to gain zero waste status.

In addition to the lack of processing facilities another issue is sorting, although the use of high-tech approaches such as x-ray fluorescence and infra-red spectroscopy may increase efficiency, especially of plastics where recycling can create enormous savings in everything from oil to water. It isn't just the percentage that is recycled that counts, but how effective the processing and recovery methods are and whether as a nation we can reduce the amount of waste in the first place. Britain is an intensely consumerist nation and as if we need further proof, our household waste continues to grow by about 3% each year.

One of the most astonishing statistics (you see, they keep on cropping up), is the estimated 17.5 billion plastic bags given away in British shops every year. This amounts to over 130,000 tonnes of plastic, very few of which are composed of biodegradable material. An example of how quickly habits could change is shown by Ireland's introduction of a tax on plastic bags in 2002, which lead to an almost immediate reduction of over 90%. What's the difference to the UK? As far as I can tell, it boils down to the simple fact that unlike in Ireland, we have companies who make plastic bags: far be it from the Government to inhibit sales within our increasingly pitiful manufacturing base.

Despite the popularity of city allotments we are so divorced from food sources as to blindly follow use-by dates without actually checking the food itself. Recent evidence, including personal experiments by yours truly, show that in many cases the dates are wildly pessimistic (fingers crossed, I haven't been poisoned yet.) Again the figures vary widely, but estimates for food wastage in Britain range from 2.5 million to 8 million tonnes per year, which even for the lower figure equates to 18 million tonnes of carbon dioxide. Food safety scares have a lot to answer for, but surely effective food science education of adults as well as children is the obvious solution? After all, it would save us at least £10 billion per year on our shopping bills.

Of course it isn't just the consumer who is at fault: British industry must bear much of the blame. Every year we each spend up to one-sixth of our food budget on packaging, much of which uses standard sizes to cut manufacturing costs at the expense of material wastage. We could do worse than look at South Korea, where over the past decade legislation has reduced both the size and materials that can be used for packaging processed foods.

Another issue is planned obsolescence. Both the Trading Standards Institute and the Office of Fair Trading investigate consumer claims of items ceasing to work shortly after the initial warranty expires, but there are plenty of less obvious instances of products deliberately built to limits short of their potential working life, such as printer cartridges and rechargeable batteries. More insidious still is the use of advertising and clever marketing, combined with long-term release cycles, to promote a more rapid replacement of items than is really necessary. This 'obsolescence of desirability' is particularly obvious with mobile phones, which rapidly outstripped manufacturer's sales estimates in the early 1990s and are now updated on the basis of a fashionable new function or user interface rather than improvements to their core purpose. There can be no better illustration of the needlessly short life span of electronic goods than the seven metre tall WEEE Man sculpture at the Eden Project in Cornwall, which is composed of the consumer goods the average British citizen gets through in a lifetime - including no less than 35 mobile phones!

One irony is that the rapid development of storage formats over the past few decades has created a cycle of obsolescence from floppy disks to laser discs at a time we most need to counter expendability. Perhaps the current generation of 'virtual' devices such as Ipods and Ipads will help offset this, as long as their material and energy costs don't outweigh the savings in paper and packaging.

We cannot be in any doubt that things are changing for the better, but the big question is whether it is fast enough. The world's third largest retailer, Tesco, plans to be carbon neutral…in about forty years time. Many office buildings are already zero carbon and the Government plans for all new homes to be built to this standard from 2016. Meanwhile the Welsh firm Affresol has developed TPR, a wholly-recyclable substance stronger than concrete yet made mostly of waste and intended to provide load-bearing walls for buildings; fingers crossed for their pilot project!

Obviously just cutting back on domestic waste and power consumption will not do as much as reducing fossil fuel usage, but every little bit helps. A final shocking statistic: every Christmas this nation uses 8,000 tonnes of wrapping paper. Do we really need that amount? And as for carbon-trading - that's a whole other issue...