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Mexican Magic |
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Written by BBI Bioenergy Australasia
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Australian company raises its glass to ethanol from agave
It helped put the smiles on Mexican faces as far back as the Aztec empire. Now the agave plant – the central ingredient of the potent drink Tequila – could be the source of wide grins in the biofuels industry as well.
South Australian company Ausagave has for the past four years been working towards growing the robust plant for ethanol production in this country.
Ausagave has been involved in market research, developing relationships with growers and researchers in Mexico, testing the plant for pests and diseases, selecting plants for future production and perfecting the tissue culture process for mass production of selected agaves.
More than 10,000 agave plants are sitting in pots and will be the subject of pilot plantings on the Atherton Tablelands and Burdekin region of Northern Queensland this year.
Don Chambers has been heading up Ausagave’s research and development. He says the company is initially looking at locations adjacent to sugar cane areas because all the necessary infrastructure to test, assess and then process is in place.
Sugar mills exploring alternatives
“Some sugar mills are keen to both expand production areas for traditional sugar-based products as well as explore alternatives,” he said. “Many growers are also looking for an alternative crop that not only utilises existing infrastructure but can also extend the processing period for the mills and spread overheads across the full year.”
Chambers says high quality selected agaves are excellent feedstock material for ethanol production because the plant can be grown in semi-arid regions.
“It does need water and will grow better when fertilised,” he said. “Agave’s use is low in comparison to other crops. Agave is non-food and certain varieties produce up to three times more sugars than sugar cane. We have used a conservative production figure of 8000 litres of ethanol per hectare. However, they are claiming two and a half times that output in Mexico. The pilot planting will confirm these figures, but even at the lower conservative numbers the crop is very attractive because of its low input requirements.”
Content reveals impressive figures
Chambers points out that agave has a sugar content of 27 to 38 percent, compared to sugar cane’s content of 10 to 14 percent. Cane produces about 6000 l/ha/a from the sugar, while certain selections of agave in Mexico have produced up to 18,000 litres per hectare.
“Added to that, agave fibre (dry biomass) has a cellulose content of almost 65 percent as against 45 percent for conifers, up to 49 percent for deciduous trees and up to 48 percent for sugar cane,” he says.
“These figures far outshine the plants that are dominating ethanol and biofuels research, development and investment today – not only in terms of potential ethanol yield per hectare but also in terms of energy balance – the ratio of energy in the product to the energy input to produce it.”
While the initial Australian agave project focus is on ethanol production, Ausagave says the fibre/biomass also has potential. It’s likely that the ethanol plantings will be in the higher rainfall areas and the biomass will be further out in regional centres where there is marginal land and a lack of water.
North Queensland’s James Cook University – a world expert expert in the biology of succulent plants like agave – has been working with Ausagave on the project. Dr Joe Holtum of the university’s School of Marine and Tropical Biology likes what he sees.
Efficient harvesting of light
“Similarities of environments here and in Mexico suggest that opportunity exists to establish a viable agave-based industry in Australia, using primarily carbohydrate accumulating Agave tequiliana cultivars that exhibit high water use efficiency and growth rates,” he said. “Agave is water-stress tolerant, less affected by storm damage than grass crops and sports a rosette leaf arrangement that permits efficient harvesting of light. It is reasonably pest resistant and has a low index of weediness. Moreover, because agave has been used in tequila making there has been considerable research on its agronomy, selection for suitable varieties and analyses of the composition of the sugars and other carbohydrates that it produces.
Aside from the Mexican export products of Tequila and Agave Nectar, other potential uses of the plant include low calorie and low GI sweeteners, prebiotics (inulin), fibres and animal feeds. All these potential value adding opportunities are dependent on demand from the biofuels industry to establish economies of scale for agave production.
Ausagave says that while the opportunities for spirit and sugar alternatives in Australia and Asia are significant, the production of products like pre-biotics can add considerable value – particularly if the crop can be underpinned by its use in the making of ethanol.
In addition to the more traditional sweetener products, Agave Nectar could provide food manufacturing and pharmaceutical industries with high quality nutraceuticals and sugar replacement products suitable for the increasing population of diabetics, hypoglycemics and the ever increasing health conscious baby boomers.
Inulins may reduce risks
Agave Nectar is used in beverages, baked products, cereals, fruit concentrates, condiments, desserts, confectionaries and other sweet foods. The market sector showing greatest growth (and hence the use of sweeteners) is beverages, especially health drinks and low calorie or reduced sugar drink alternatives.
Ausagave says the opportunities for spirit and sugar replacement are significant, but it is the pre-biotics used in functional foods, namely agave inulin, that is attracting considerable interest.
Agave inulin is a fructo-oligosaccharide rich material. It is a water-soluble, non-digestible dietary fibre that enhances the growth of beneficial Bifidobacteria.
The scientific evidence for the functional claims of inulin-type fructans is well documented. Because they are both non-digestible and a dietary fibre, inulins may reduce risks associated with constipation, infectious diarrhoea, cancer, osteoporosis, atherosclerotic cardiovascular disease, obesity and non-insulin dependent diabetes.
On the biofuels side, Ausagave says an unprecedented interest in bioenergy in both the international and national arenas – and from investors and engineers keen to promote new bioenergy technologies – means that bioenergy is becoming a tangible option for the future.
But it warns that while a new bioenergy and bioproducts industry which replaces fossil fuel products could be a boon to farmers looking for profitable diversification options, it is vital to ensure that any new large-scale industry has an environmentally sustainable future. The future availability of water, for example, needs to be considered.
Potential investors get the message
Ausagave says the plants for the Australian project have been selected from some of the best fields in Mexico, and then further selected for vigour and disease resistance to ensure the company has the best planting stock available.
Discussions and presentations to potential partners/investors are underway, as is the identification of suitable land with the correct climate and growing conditions. The company has used the CSIRO and the Bureau of Meteorology to model potential crop production sites.
Ausagave’s Don Chambers says growers in South Australia, New South Wales and across Queensland have shown interest in trialling the crop.
“We are conducting trials here in South Australia and all has progressed well to date,” he said. “But because it is colder – and that is also when there is moisture (winter rains) – the plant does not grow very quickly. There will be quicker growth in Queensland, where the climate is more similar to that in its native habitat in Mexico.”
Chambers believes liquid biofuels, including ethanol, will be a part of the renewable energy landscape for many years to come.
“All the infrastructure is in place and only minimal changes – if any – are required to supplement oil,” he says. “Many of the alternatives are still in the research and development phase and then they will have to be integrated into the existing infrastructure and markets.
“On the flip side, if ethanol is not promoted and supported by existing industries such as sugar, cane growers could lose a significant market opportunity as other crops may fill the void.”
Reprinted with permission, May 2009. BBI Biofuels Australia Pty Ltd
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