Bioethanol Production

1st INTERNATIONAL CONGRESS ON NATURAL SCIENCES (ICNAS-2021), Erzurum, Türkiye, 10 - 12 Eylül 2021, ss.312-318

The interest in alternative fuels has been increasing worldwide due to reasons such as

the negative effects of fossil fuels on the environment, global warming, the significant

decrease in energy demand in the world and negative conditions in the oil market. The

features of alternative fuels such as significantly reducing greenhouse gas emissions,

meeting the worldwide need for raw materials and being able to be produced from

renewable raw materials make these types of fuels attractive. Bioethanol, a regular fuel

form, is regarded as the one of these alternative fuels and is the most prevalently used

fuel type. Ethanol, whose chemical formula is C2H5OH, is a flammable, clear, colorless

and slightly toxic chemical compound. It can be produced from petrochemical raw

materials by acid-catalyzed ethene hydration or from various raw materials by

fermentation. Fermentation processes occur with the use of microorganisms such as

bacteria, yeast and filamentous fungi. Both yeasts and bacteria are able to efficiently

convert sugars to ethanol through fermentation processes. The gram-negative bacteria

Zymomonas mobilis and the yeast Saccharomyces cerevisiae are reported as the most

used microorganisms for bioethanol production. In order to make ethanol production

more economical, low-cost organic wastes or byproducts such as molasses, whey,

starch, fruit peels and cellulosic materials are suggested to be used as carbon source

and/or complex substrates in the fermentation medium.

Keywords: Ethanol, Fermentation, Zymomonas mobilis, Saccharomyces cerevisiae