One of the most commonly used forms of fuel for automobiles is petroleum. Within recent years, scientists have been finding other sources of fuel for automobiles. Scientists must use different catalysts in order to change some of these sources into fuel such as ethanol. Different bacteria are used to create some of these alternative fuels. Bacteria’s role in bioenergy is to change different sources found in nature into fuel. Ethanol is a type of fuel made from corn and that is readily found in nature. Corn is turned into ethanol through a careful selection of bacteria. The selected bacteria act as enzymes that produce a chemical change that turns corn into ethanol. Different types of bacteria are being researched in order to determine what bacteria is best used in creating ethanol. Algae is another source of fuel in which scientists are experimenting. Scientists are currently trying to find other sources of fuel that are the most energy efficient. Sources that have low energy efficiency costs a lot of money to produce and yields very little energy, and this means they are not ideal sources of energy. For instance, hydrogen is ubiquitous, or heavily abundant, in nature. Due to the ease of procuring hydrogen, scientists are exploring ways of turning it into a source of fuel. Current processes of turning it into a fuel, however, are costly, and it has small energy yield.