Bioethanol, a carbon dioxide neutral energy source

31 March 2022 | Afroditi Vaitsopoulou

Did you know that:

  • bioethanol is a climate friendly energy source,
  • does not pollute the atmosphere,
  • is carbon dioxide neutral,
  • and can be produced from agricultural food and waste products?

Bioethanol is a renewable and sustainable high octane number biofuel, which can be produced from fermentation of corn, potatoes, grains, sugar beet, sugar cane and vegetable residues. Instead of burning agricultural waste products such as rice straw, we can convert it into bioethanol, thereby increasing its value. As these resources can be easily regrown, they are sustainable and make us independent from fossil fuels. By producing bioethanol, we can save the planet. So let us invest in our future!

Bioethanol

What is Bioethanol and how it can be produced?

Bioethanol is a renewable and sustainable fuel source. (Aditiya, Mahlia et al. 2016). The fact that it is non-toxic, highly oxygenated, and biodegradable makes its combustion cleaner, without soot, ash or harmful emissions that can compromise our health and the environment (Domínguez-Bocanegra, Torres-Muñoz et al. 2015). In addition to the cleaner combustion, bioethanol production is also a green process that uses biomass instead of fossil fuels. Biomass such as sugarcane, crops like grain and food waste can be used as nutrients for a bunch of microorganisms. These organisms are capable of converting or metabolizing the nutrients into bioethanol. This process is called fermentation (Aditiya, Mahlia et al. 2016).  Fermentation is a very popular, traditional and well-established natural metabolic process in which cells transform complex carbohydrates into simple sugars and ultimately into alcohols or acids (Hossain, Haji Zaini et al. 2017). Fermentation is a very common term that is used to describe beer production and explain why our muscles keep working during intensive exercise while being low on oxygen. In both cases, what happens is a fermentation while, for the first one, yeast converts glucose in alcohol and for the second case, our muscles generate lactic acid. Fermentation is a widespread term that can be applied in the context of bioethanol production as well. Usually Bioethanol is synthesized from alcoholic fermentation of sucrose or simple sugars of diverse types of biomass (Hossain, Haji Zaini et al. 2017). 

What kind of microorganisms can be used to produce bioethanol?

Ethanol can be produced by different types of microorganisms, including yeasts, bacteria and fungi. Among all, the yeast Saccharomyces cerevisiae and Schizosaccharomyces pombe represent the favourite microorganisms for the industrial production of bioethanol. They are capable of fermenting a diverse range of substrates and converting them into bioethanol under anaerobic conditions (without oxygen) (Domínguez-Bocanegra, Torres-Muñoz et al. 2015).

Why is the yeast S. cerevisiae so attractive?

Among the microorganisms above, S. cerevisiae is the most common, available and inexpensive worldwide. Recombinant yeast can be easily genetically engineered and modified. Usually due to post-genetically modifications, yeasts bring out a higher ethanol yield than the usual one. Researches proved that at a lab scale, recombinant yeast exhibited revolutionary bioethanol yields and higher capabilities of fermenting pentose sugars. Several factors play a role in the fermentation process, such as temperature, pH, nutrient medium components, reducing agent, etc.. These factors have a great impact in the yield and costs of bioethanol production. (Hossain, Haji Zaini et al. 2017).

Why is bioethanol important to us?

The interest in bioethanol has emerged from the air pollution caused by fossil fuels and their limited availability. The extensive use of fossil fuels causes the release of an immense amount of greenhouse gases and large price hikes.(Sarkar, Ghosh et al. 2012, Rastogi and Shrivastava 2017).  During combustion, the emissions from bioethanol are heat, steam and a small amount of carbon dioxide. Carbon dioxide is absorbed by plants, it is then processed via photosynthesis to help the plants grow. This infinite cycle of creation and combustion of energy makes bioethanol a carbon neutral fuel source.

Closing

Bioethanol is an amazing energy source! It’s great amounts of applications are the reason for the high interest at an industrial and personal level. We can save the planet by reversing climate change if we invest in bioethanol production. These investments need to go into the development of the biorefinery industrial sector that is responsible for the production of bioethanol.
Find out more about biorefinery in our next article: Biorefineries. Bioethanol is only one of many valuable products that can be produced using biorefinery. In the following article "Malic acid is part of your daily life" you can read more about them.
The urgency of reversing climate change is real! Read our article "Climate change is a reality and it affects us all" to find out the reasons why this is.