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RENEWABLE ENERGY BREAKTHROUGH

Hope for Spain’s ailing biofuel sector

After four years in decline, scientific breakthroughs could help the industry, which employs thousands of people

Agricultural waste, such as these oranges, is a sustainable source of biofuels Ampliar foto
Agricultural waste, such as these oranges, is a sustainable source of biofuels

A decade ago, biofuel was being touted as the answer to the world's fuel needs and Spain, a pioneer in renewable energy and a country that imports all its oil, invested heavily in the sector. But five years into a deepening recession, Spain's biofuel industry has increasingly begun to look like it faces closure, putting the jobs of more than 6,000 people at stake. But a new discovery might provide the help it needs.

In the late 1990s, backed by state support, companies such as Cepsa, Abengoa, Acciona and Ebro Puleva invested some 1.8 billion euros in building around 50 biodiesel and bioethanol refineries.

At the height of the optimism over biodiesel, a group of companies headed by Repsol YPF set up the CENIT R&D biodiesel project to develop technology to reduce greenhouse gases and Spain's reliance on oil imports, as well as increasing the use of biodiesel, reducing production costs, and increasing the availability of local raw materials.

Similarly, Abengoa Bioenergía pioneered bioethanol production in Europe. At their height, its three plants in Spain produced more than 500 million liters per year, with operations in France and the United States. According to the European Biodiesel Board (EBB), biodiesel production in Spain experienced a five-fold increase between 2004 and 2005.

But in the last few months 10 factories have closed, while most other plants have reduced their workforces and output. In 2012, biodiesel production was around 10 percent of capacity, with bioethanol at around 65 percent of its potential output. The turning point for the Spanish biofuel industry was 2008.

Biofuels do not significantly reduce carbon dioxide emissions

Up until then, the country opened one production plant after another, funded by government money and benefitting from tax breaks. The goal, in line with EU environmental objectives, was for renewable energy to make up at least 10 percent of transport fuel by 2020. But that year saw a record high in cereal prices, effectively making it uncompetitive for many countries to continue dedicating valuable land to growing the vegetable mass required to produce biofuel.

Since then, debate over whether to grow food or material to make biofuel has continued, in large part encouraged by evidence showing that biofuels do not significantly reduce carbon dioxide emissions. Another blow to Spain's hopes of becoming a leading biofuel producer has been cheap imports. Spanish companies have accused Argentina and Indonesia of imposing taxes that encourage the export of finished biodiesel over soybean oil.

The EU imposed restrictions on Argentinean biofuel imports in June, but the sector says they are insufficient. Meanwhile, to add to their woes, the government has decided to end tax breaks for biofuel producers. The EU also says it is considering limiting the use of biofuels produced from vegetable matter grown exclusively for this purpose.

But an article in this month's online edition of Science Express magazine could offer hope to Spain's ailing biofuel sector.

An international collaboration of plant scientists from VIB and Ghent University, the University of Dundee, The James Hutton Institute and the University of Wisconsin has identified a new gene in the biosynthetic pathway of lignin, a major component of plant secondary cell walls that limits the conversion of biomass to energy.

Researchers have been studying the lignin biosynthetic pathway in plants

"This exciting, fundamental discovery provides an alternative pathway for altering lignin in plants and has the potential to greatly increase the efficiency of energy crop conversion for biofuels," says Sally M. Benson, director of Stanford University's Global Climate and Energy Project.

To understand how plant cells can deliver fuel or plastics, she explains how a cell wall works. A plant cell wall mainly consists of lignin and sugar molecules such as cellulose. Cellulose can be converted to glucose, which can then be used in a classical fermentation process to produce alcohol, similar to beer or wine-making. Lignin is a kind of cement that embeds the sugar molecules and thereby gives firmness to plants. Thanks to lignin, even very tall plants can maintain their upright stature. Unfortunately, lignin severely reduces the accessibility of sugar molecules for biofuel production. The lignin cement has to be removed via an energy-consuming and environmentally unfriendly process. Plants with a lower amount of lignin or with lignin that is easier to break down can be a real benefit for biofuel production.

For many years researchers have been studying the lignin biosynthetic pathway in plants. Increasing insight into this process can lead to new strategies to improve the accessibility of the cellulose molecules. Using the model plant Arabidopsis thaliana , the international research collaboration has identified a new enzyme in the lignin biosynthetic pathway. This enzyme, caffeoyl shikimate esterase (CSE), has a central role in lignin biosynthesis.

Knocking-out the CSE gene resulted in 36 percent less lignin per gram of stem material. Additionally, the remaining lignin had an altered structure. As a result, the direct conversion of cellulose to glucose from un-pretreated plant biomass increased four-fold, from 18 percent in the control plants to 78 percent in the CSE mutant plants.

These altered plants are, formally speaking, transgenic, which could prompt resistance from environmental groups about their use. But the team says that a transparent approach to developing them, accompanied by information explaining that they are not intended for consumption, could provide Spain's biofuel industry with the key to the future, as well as meeting the EU's emission reduction targets.