The picture represents the various stages of biofuel production. As an example, this scheme describes the industry of biofuel such as ethanol.
This complex process is cyclical. It begins with conservation energy of solar and carbon dioxide in forests. As the result, trees grow. Later, plants should be harvested and pre-processed to obtain a special substance called cellulose. These fibers are usually used to produce sugar in a factory or laboratory. Microbes feed on sugar. And only as the result of their vital activity is ethanol obtained.
Ethanol is capable to use for different machines such as cars, trucks, airplanes and others. As the result of consumption of this type of fuel, carbon dioxide id formed. And this chemical entity, as mentioned before, might be involved by trees in this cycle again.
To sum up all this processes, it should be noticed that this biofuel, ethanol, is recyclable. There are several levels of its production. In addition, it is able to apply for the needs of society.