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Energy from waste: Valorising the biorefinery concept


Dr Paul Hudman

Dr. Paul Hudman at the Industrial Biotechnology Innovation Centre (IBioIC) discusses the rise of biorefineries in clean energy production.

The concept of biorefining centres is based on the utilisation of all the elements of biomass input, recycling secondary products, valorising all co-products and even producing the very energy which powers the process itself. This directly mirrors the operation of a petro-chemical refinery, where crude oil is separated into a range of marketable products across the chemical and fuel value chains. The crucial difference however is that biorefineries are fed with renewable materials compared with the fossil feedstocks used in the petro-chemical industry.

The use of all components of the biomass is vital in terms of the economics of the process as a whole. Ideally, a mix of high-value, low-volume products (such as cosmetics and nutraceuticals) and low-value, high-volume products (fuels and energy) will be produced. The high-value products enhance profitability, the low-value products provide scale. Any potential recycling of the low grade heat from the process itself following circular economy principles closes the loop. 

Replacing the oil barrel

Given the current policy landscape, most biorefineries focus on biofuels due to subsidies and incentives that make them attractive to produce. Such are the similarities between petrochemical and bio-based refineries that retrofitting is now a possibility. Since 2009, the energy division of the US Department of Agriculture has been promoting a ‘Biorefinery Assistance Program’ - a federal loan that assists in repurposing disused oil refineries into plants that process biological material. By the year 2014, a program level of approximately $181 million had already been supported. 

The USA is in fact one of the global leaders in the development of biorefineries; most developments here focus on maize for bioethanol and soya for biodiesel. Biological feedstocks include purpose-grown crops (such as sugarcane), woody plants and algae. Many feedstocks are ‘lignocellulosic’ in their nature - they consist of carbohydrate polymer (cellulose and hemicellulose) and an aromatic polymer (lignin). 

A lignocellulosic feedstock like sugarcane is extremely resistant to natural breakdown. Acid (for example a 0.5% solution of sulfuric acid) is used to encourage the feedstock into exposing its valuable component sugars, primarily the polymeric cellulose. Pre-treatment can also yield desirable by-products like lignin. Highly lignified wood is durable and therefore a good raw material for many applications. It is also an excellent fuel, since lignin yields more energy when burned than cellulose. After pre-treatment, the cellulose is broken down into its constituent monomers. Industrial biorefineries will use a number of enzymes (including cellulase) that work cooperatively to break down cellulose through hydrolysis. Once the hydrolysis of cellulose into glucose has been completed, microorganisms can begin the anaerobic process of fermentation into ethanol.

Brazil is mainly developing biorefineries focusing on the use of sugarcane as a feedstock for making bio-ethanol. Some 22 million acres of land is inhabited by sugarcane plants. In 2008, 61% of Brazil’s total sugar yield went on to produce 7.3 billion gallons of bioethanol. In other countries, feedstocks for biofuels are different based on agricultural production – in China bioethanol is produced from corn, manioc and rice whereas in Japan it is refined using rice, wheat and brown seaweeds. In India, biodiesel is produced using palm oil and jatropha. 

Beyond biodiesel

Where policy incentives may drive the conversion of feedstock to fuel; economics will drive the production of high-value chemicals or chemical intermediates from potentially similar sources. These two outcomes need not be mutually exclusive and we are seeing the commercialisation of processes where fuel and high value products are created together to ensure the maximum economic benefit is extracted per tonne of feed material.

In 2009, in the midst of the recession, the Norwegian government launched a 20 billion krone (equivalent to $2.9 billion) stimulus package. Of this, $418 million was set aside for biotechnology companies based on the concept that aside from the fossil fuel replacement products, ‘biotechnology has the potential to solve many of the major global challenges of our time. The application of biotechnology to aquaculture and agriculture will lead to more reliable access to safe food for the world’s growing population. New, innovative health services will improve medical treatment options while reducing the negative effects of medication.’   

Take, for example, Scottish industrial biotechnology company GlycoMar Ltd, which is currently collaborating with Norwegian firm MicroA which has developed and patented a ‘photobioreactor’, a chamber that allows the controlled and optimised growth of microalgae. Polysaccharide molecules produced by the algae, Prasinococcus capsulatus, have natural anti-inflammatory and anti-viral properties, making them an attractive proposition for use in the cosmetics and nutraceutical markets, potentially in sunscreens, moisturisers and wound care products. The research is the first in a series of projects, funded by the Industrial Biotechnology Innovation Centre (IBioIC), which will increase the UK economy’s share of the predicted £360 billion industrial biotechnology global market. 

Following the success of the project, IBioIC member Glycomar Ltd and MicroA formed Prasinotech Ltd, the first algae refinery in the world built to manufacture these polysaccharides from microalgae. The first two products from Prasinotech Ltd will be active ingredients for use in cosmetic skincare which will have a combined annual value of £1 million in the third year of production.

Integrate to valorize

Norway’s Borregaard facility is a great example of an integrated biorefinery – one which delivers production of goods it is specifically designed for but which also exploits local, abundant feedstocks to produce other useful chemicals. Borregaard is one of the world's most advanced and economically sustainable biorefineries with a variety of chemicals in production. Under its ‘LignoTech’ hat it is a leading supplier of lignin-based products; via its ‘Synthesis’ section it is also a leading supplier of fine chemicals for the global pharmaceutical market while Borregaard Ingredients holds a strong position within vanillin for foodstuffs. Borregaard ChemCell is a leading producer of cellulose and also, based on the locally abundant Norwegian forest, ChemCell uses timber as a feedstock to produce bioethanol. 

This key principle of integration is echoed by the Scottish Government’s desire to embrace a more circular economy and to encourage us to utilise all ‘waste’. IBioIC is working on this principle with GSK through a project to generate fermentable sugars from locally available waste streams. Whether this is timber waste from nearby forestry operations or paper waste from local mills the common theme is that it all contains cellulose. This sugar will be used to replace corn-based glucose in GSK’s process with the remaining plant material being burnt to produce heat and power for the site.

Although this example sits in the central belt of Scotland, ‘stranded’ resources could be unlocked with local solutions such as local low carbon demonstrator projects, which show a local energy economy approach, linking local energy generation to local energy use. In this area, IBioIC is supporting Xanthella, a small industrial design company that is working on producing systems to grow microalgae. They are championing the use of algae as a new high value industry for remote and rural areas by using cheap renewable energy to power the photobioreactors that are used to grow the algae. 

A concern with using crops as the raw materials is the competing use for arable land. The food vs. fuel debate has led to some negative public opinions of bio-fuels and ecological questions over their sustainability in the long term. Algae can be grown on brown field sites in enclosed vessels not needing the large acreage typically suitable for agriculture. Scotland also boasts a long coastline and prominent continental shelf, both of which are suitable habitats for growing macroalgae. Some strains of cultured algal seaweed can increase their biomass by up to 5% a day. This rate of growth far exceeds even the fastest woody crops. Algae also have high protein and oil contents, which could be used to make valuable chemicals.

The ASLEE (Algal Solutions for a Local Energy Economy) project will look at the technical and economic viability of creating a predictable and flexible demand for renewable electricity through manufacturing in remote and rural areas, producing a sustainable competitive advantage. The project will also investigate how biomanufacturing can allow more deployment of renewables in these areas through electricity demand and grid balancing thus benefiting the local economy. The aims of much biomanufacturing are high value, low volume products at a scale compatible with local resources. The growth of algae matches these requirements and makes the project the first in the world to take this whole system approach and incorporate a number of innovative technical and economic features. Integrated biorefining supporting rural economic development is also valued in Canada – the integration with existing bio-based industries (forestry and agriculture) is seen as a way to reinvent these industries and add value to agriculture through the use of existing infrastructure.

The concept of biorefinery is still in early stages at most places in the world. Challenges around raw material availability and homogeneity, mapping of the value chain, and scalability of the model need to be addressed before its realisation at commercial-scale. Although much of the technology is still in nascent stages, it holds the key to the optimum utilisation of wastes, co-products from many industries and natural resources that we have always tried to achieve. 
 

ABOUT THE AUTHOR

Dr Paul Hudman is Business Development Manager at the Industrial Biotechnology Innovation Centre.
 

FURTHER INFORMATION

Industrial Biotechnology Innovation Centre (IBioIC)  http://www.ibioic.com/ 

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