Final answer:
The anaerobic fermentation output commonly used as biofuel is methane, which is created from organic waste via anaerobic bacteria. Additionally, ethanol, produced by fermenting plant-derived sugars, is a significant biofuel, particularly for transportation. Both methane and ethanol offer alternatives to fossil fuels but raise concerns about land use and food production competition.
Step-by-step explanation:
The anaerobic fermentation output that is commonly used as biofuel is methane. Methane production occurs during the process of anaerobic decomposition or fermentation using anaerobic bacteria. This process can convert organic waste, such as livestock manure, municipal sewage, and garbage, into methane gas. Methane is a clean-burning fuel that can be used for electricity generation in power plants or supplied to homes for heating. Additionally, ethanol, another bioproduct of fermentation, is prominently used as biofuel, especially in transportation. Ethanol can be produced by fermenting plant-derived sugars and is known for being the chief biofuel, making up about 80% of total biofuels.
It is worth noting that while bioethanol and biodiesel provide an alternative to fossil fuels, they also pose challenges such as competition with food production and the sustainable use of land. These biofuels may be manufactured from plant sources that are not used for food, like stalks or cellulosic matter, to mitigate some of these issues.