First published in Cleantech magazine, July 2008. Copyright Cleantech Investor, 2008

Simon Bennett continues the series on biorefineries with a look at the algal biorefinery.

Simon Bennett is a researcher in the Centre for Energy Policy and Technology (ICEPT), Imperial College London, and part of the EU Biopol biorefinery consortium. Bioscience for Business can be found at www.biosciencektn.com

Shell Hawaii, Biofuel Project USA, 2007 (image courtsey of Shell)

In a previous issue, Cleantech magazine reported on recent advances in algae research as being amongst the most exciting in the biofuels area. Since then the hype has continued apace, with references to the designer algae of the future confidently trailing almost every discussion of advanced biofuels. In April KLM hit the news by partnering Dutch firm AlgaeLink in the search for a future jet fuel. They have rather immodestly suggested that 7% of their fleet will be powered by 100% algal biofuel by 2010.

However, this news landed as some scientists are questioning the scales that can be sustained for algae-to-biofuels production without some major technological advances. In an article in American Scientist magazine, Gerald Cysewski, President of Cyanotech Corporation, is on record as saying that “in the laboratory, you can create some very efficient bioreactors, but it just isn't scalable.” Cyanotech currently produces food supplements from algae in Hawaii, where Shell began an algal biodiesel venture with HR Biopetroleum earlier this year.

Could incorporating low-volume, high-value chemical products as a step on the way to large-scale algal biofuels offer a business model for more rapid deployment?

Attention is focused on microalgae, extremely primitive marine plants lacking the physical structures that support land plants and macroalgae such as seaweed. Microalgae have very high photosynthetic rates which allow them to translate sunlight into high rates of biomass growth that are unavailable from crops, e.g. at least ten times the yield per hectare compared to palm oil. Apart from a small amount of nutrients, their only requirements are a water supply and a CO2 feed, both of which can be taken from waste sources such as power station chimneys.

There are many thousand species of algae, even in British waters, and all contain proteins, vitamins and oils that can be farmed and extracted. This offers a huge screening challenge, but a great chance of finding organisms with better attributes for industrial applications. These attributes include higher concentrations of natural oils, usually between 20% and 40% by weight, making algae particularly suitable for biodiesel production, which currently relies on other sources of vegetable oil such as rapeseed or palm.

This combination of extractable chemicals, high procreation rates and variety of breeds has led algae to be termed ‘factories’ for the materials of the future. Furthermore, as non-food resources which are supported off-shore or on infertile land, algae may be the only route to the sustainable displacement of high proportions of oil consumption.

How integrated must they be to be sustainable? Should they include industrial clusters or single enterprises? Will heat and power be considered to be valuable products, or should they be a last resort? Nobody seems to have any ready answers, except that today’s single-product biofuel refineries should one day evolve a greater resemblance to complex modern oil refineries, efficiently upgrading by-products by exchanging waste streams and services. Where algae are concerned, however, it seems that the high-value co-products have led the way so far.

Algal biomass contains natural oils, carbohydrates and proteins. The natural oils are targeted for biodiesel production, and carbohydrates might be fermented to ethanol if extracted in sufficient quantities. These uses were investigated extensively by the US Aquatic Species Programme (ASP), which ran until 1998. It was initiated by the Federal Government after the 1970s oil shocks and is the most comprehensive study of algae to date, ultimately being abandoned as low oil prices ruled out hope for biofuels. One legacy of the programme was the development of advanced techniques for screening, cultivating and separating out the components of algae. As a result, the first products to hit the market were not green fuels, but high value extractable proteins and vitamins produced to high quality by certain algae acting as tiny factories.

Spirulina is the poster child of commodity algae production. It is a species that yields unusually high amounts of proteins and vitamins, which has made it a success with health food producers. Industrially it probably benefited enormously from the lessons of the ASP, which provided insights into the design of controlled ‘raceway’ ponds. These facilities are open ponds that circulate water and nutrients. They have now appeared in the US, Taiwan, Israel, Mexico, China, Japan and India, and production is thought to exceed 3,000 dry tonnes per year for nutritional supplements and animal feed.

Another algae, chlorella, was once thought of as a future mass food supplement due to its high protein content, but has since found a niche in cosmetics where it is used, for example, to stimulate collagen synthesis. Strains of spirulina are also incorporated in products that promote skin tightening, for instance by Monagasque firm Exsymol. The Swiss-based Pentapharm also uses an algal ingredient in skincare products.

Other markets for microalgae products use the presence of extractable natural oils. In particular, the multi-billion dollar infant food market is attractive to companies such as Frankfurt-based Nutrinova and Colorado-based Martek, a market leader in the production from algae of Omega-3 fatty acid, which may have a range of health benefits such as the reduction of heart disease. ß-Carotene, with a market value of up to $3,000/kg, is produced in Australia, by Cognis Nutrition and Health, and in Hawaii.  

The US’ ASP, which was aimed at energy security, supplied some of the tools and awareness for biotech firms to move into speciality chemicals production. Now that the emphasis is shifting back to fuels these high value products could radically enhance the economics of large-scale aquaculture. Companies like Proviron, in Belgium, with a history in the fine chemicals industry but which have diversified into biodiesel, are now looking at algae as a bridge between the sectors.

As a feedstock, algae could fit into most of the integrated biorefinery designs that are on the drawing board as its primary components might be optimised to produce more oils, carbohydrates or proteins. The challenge lies in the identification of better species and reducing the costs of production, which are currently an order of magnitude above other biofuel systems.

Identifying new and better algae is predominantly a screening challenge, especially in Europe where genetically modified organisms (GMOs) remain unwelcome. Microbiologists have been working on remarkable high-throughput techniques for finding the best organism for the job, but they need to know what ‘the job’ is. Maximising lipids is an obvious candidate, but investors in such long-term projects will reasonably want to know whether oil-based biodiesels are likely to be replaced by designer diesels from gasification, pyrolysis or fermentation in coming decades. Furthermore, only a few hundred of the tens of thousands of micro-algal species have yet been investigated for potential pharmaceuticals and nutraceuticals. Combining the objectives of multiple products (see diagram) is an immense challenge.

But are there more concrete steps that can be taken now towards the advanced systems of the future? A suggestion for low-cost production today is to use mixed algae as a part of the sewage treatment process. If it can produce large amounts of biomass in sewage lagoons, then this can be transported to plants using pyrolysis or other thermal bioenergy processes. Raceway ponds will continue to be deployed in sunny locations for speciality chemical products, thus constantly improving the technology. However, these approaches limit the scale of energy production by the small market sizes of the profitable applications.

Ultimately closed system tubular installations using captured carbon dioxide from power plants will hopefully be scaled-up for commercial production of tailored algal monocultures. These so-called photobioreactors were written off as too expensive in the 1990s, but are making a big comeback with investors in the current climate. They are still far more carbon intensive than open ponds; but research publications on photobioreactors far outweigh those on open ponds, so there is hope that energy efficiency can be improved beyond the contemporary practice of shining UV light 24 hours a day on intensively cleaned plastic tubes.

As with other biorefinery ideas, the use of algae presents numerous routes to the future integration of raw materials, processes and products. To address some of these conflicts and challenges the Carbon Trust will launch in September a call for algal bioenergy research in the UK. The resulting Algae Fuels Initiative projects are scheduled to begin in 2009 and are currently under assessment, but will hopefully cover screening, mass production technologies, and protein fractionation for biorefinery-type applications.

Strongly supporting the Carbon Trust is the Government-funded Bioscience for Business Knowledge Transfer Network (KTN). Meredith Lloyd-Evans is a Knowledge Transfer Manager at Bioscience for Business, coordinating efforts in moving British industry away from non-renewable resources to biorenewables. He would like to see the UK apply its existing excellence – in culture collections and fundamental research – to high-throughput screening. The Bioscience KTN sees screening for new organisms as crucial to improving algae’s commercial prospects in Europe, and a key subject for collaboration between industry and academia.

In an area that has been dominated by technical and economic arguments limiting applications to open ponds in places with high light intensities, Mr Lloyd-Evans would like to see such notions challenged. “Technology for use in temperate zones has moved on,” he tells me. “We are aiming to have a large scale demonstration of one of these concepts within three to five years, such as the use of disposable plastic bags for large-scale, inexpensive bioreactors.”

Despite this revival of interest and funding he admits that “successful implementation of algal bioenergy systems does have some serious challenges to overcome, including unexpected topics such as local planning laws and waste regulations. We also need to think hard about whether the target is successful biofuels production alone, or embedded in a biorefinery with other output streams such as fine chemicals, nutraceuticals and better water.”

Whilst sceptics remain, it may just be possible that the current hype will finally help to drive the development of efficient bioreactors out of the laboratory. But it seems that the integrated biorefineries of the future might be waiting for integrated action today to define the targets for this designer biomass.

The entrepreneurs and innovators are ready; the carbon dioxide source is there to be used; and the fuels market is waiting. Commitment to go for one or two commodity products is now needed to guide research, develop the right production processes and identify valuable chemical co-products that can overturn the economics.

An outline of a future Marine Biorefinery - from René van Ree & Bert Annevelink (2007), Wageningen UR and Biopol consortium