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‘A century ago, petroleum – what we call oil – was just an obscure commodity;
today it is almost as vital to human existence as water.’
We live in a world composed of ancient sunlight. Literally. Look around you – almost every object you see has a history that starts with simple chemical building blocks synthesized from petroleum- fossilized carbon trapped by photosynthesis and buried for millenia.
Your toothbrush, shoes, medicine and shampoo… all of these things are the ultimate fruits of the oil and chemical industries.
In fact, the material standard of living we enjoy in 21st century societies is to a large extent founded on the chemical processing of petroleum products.
A state of affairs which could be viewed as problematic, to say the least. We all know the issues, even if we try to avoid the consequences – climate change, war and terrorism, political corruption, dependence on non-renewable resources…sometimes it seems as if our dreams of affluence are becoming the stuff of nightmares. At the root of it all lies our reliance on non-renewable forms of carbon.
Of course, there are always alternatives. A growing number of scientists recognize the need to move away from oil-based feedstocks for our chemical and materials industries, and towards a sustainable economy based around the use of renewable carbon and non-polluting energy sources. At the centre of this alternative vision for 21st century manufacturing is the biorefinery. By analogy to an oil-refinery, the biorefinery takes in carbon in the form of biomass and converts it, by various chemical or biochemical methods, into so-called ‘platform’ chemical building blocks such as ethanol, xylitol and succinic acid. These ‘platform’ molecules provide the raw building blocks for a bio-derived chemical industry, feeding into the production of everything from bioplastics to drugs.
Of course, just because you are using a bunch of plant material as a feedstock does not guarantee the carbon-neutrality or broader sustainability of your shiny new biorefinery.
There are two key issues scientists must work on to ensure that the biorefinery concept is a genuine advance, truly leaving behind the polluting petroleum industry of the past.
1.The first issue is kind of obvious – where does all this biomass come from?
The ‘food or fuel’ debate of 2008 illustrates the complexity of this issue. For various reasons, largely to do with domestic politics, the US government has heavily promoted the bio-refining of corn into ethanol for use as biofuel. Unfortunately, it turns out that using a staple food crop for transportation fuel is not such a smart idea – the process actually increases carbon emissions, and, what’s more, the conversion of ‘food to fuel’ has been partly blamed for the devastating food crises of 2008 caused by rising food prices.
Much better prospects lie in the use of lignocellulose (the indigestible parts of plants), food wastes, or even seaweed and algae (the ‘ocean-based’ biorefinery neatly gets over the ‘land-use’ problems associated with traditional biorefinery concepts). Ideally, a biorefinery will be able to tolerate a ‘mixed’ input stream, taking advantage of whatever wastes are available locally at any given time.
2.The second issue relates to what we do with all that biomass once we truck it in to our facility.
The key idea is to use the developing technologies of green chemistry for the extractions and conversions required to produce the ultimate products. After all, what is the point of going to all the trouble of sourcing renewable biomass if we are going to use dirty and dangerous processes for its conversion?
The University of York Green Chemistry Centre of Excellence has done pioneering work in this area, showing how green technologies such as microwave pyrolysis and extraction with supercritical CO2 could be applied in an ‘integrated biorefinery’ concept – I highly recommend checking out some of their reviews, linked to below.
So much for theory – by now you are probably hoping for a shining example of all of this. Of course, the replacement of our petrochemical industries is going to be an iterative process, with a long and sometimes steep learning curve. One inspirational company I can tell you about today is Blue Marble Biomaterials, based in Montana. These guys are making food and cosmetic specialty chemicals from biomass using some pretty neat biochemistry, and are addressing many of the issues talked about here in their processes. Why not check them out while you wait eagerly for my next post, which will tell the story of how an obscure Italian chemist studying plants in the early 1900s conceived and began work on a chemistry powered by sunlight…
Links for further information:
‘Green chemistry for the second generation biorefinery’ – DOI: 10.1002/jctb.1710
‘Green chemistry and the ocean-based biorefinery’ –
Blue Marble View blog – http://blog.bluemarblebio.com/