Biomass energy

1987/02/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Energia berriztagarriak

Fungi can turn plants into enemies of oil. American scientists have identified fungi that can completely reduce the process of transforming biological material into ethanol.

Ethanol is the enemy of gasoline, as the current car can circulate with 20% ethanol. In addition, ethanol can replace lead in the process of raising octane level. However, ethanol is much more expensive than gasoline and efforts to reduce it have been sterile.

The ethanol obtained with the fermentation of biological material must compete with that obtained from oil. For example, hydrolyzing ethylene obtained with oil cracking is cheaper than fermenting sugar. When oil prices rose in the 1970s, fermentation seemed a way of synthesis of ethanol. Currently, when the cost of oil has decreased, fermentation seems less useful. The recent discovery in the United States can revolutionize the situation.

The biological material of the plants is composed of 70% cellulose and hemicellulose. This biological material can contain many sources; agriculture, forest, plant food treatment, etc. Recycling this waste and this waste has two objectives: reduce pollution and get fuel.

Ethanol synthesis requires microorganisms that can work with biomass. However, first of all, you have to put the biomass in a digestive way. Long molecules that form cellulose and hemicellulose must be broken with hydrolysis until complementary sugars are obtained. Hydrolysis of vegetable biomass produces a large amount of fermentable sugar. Most microorganisms drown in sugars or kill the ethanols that produce them. The medium should be diluted so that microorganisms can live and stop the reaction before the ethanol concentration reaches lethal levels.

The new fungus, called Paecilonyces sp (NF1), has clear advantages over other microorganisms. It can withstand higher concentrations of sugars and convert them into high-quality ethanol. In addition, it is able to withstand high temperatures, 43°C, and sufficient acidic media. During a 7-day process it generates 0.4 g of ethanol of 1 g of sugar.