Guest Blogger, Matt Spadafore, Undergraduate in Microbiology
Whether we want to admit it or not, the party scene has a huge cultural impact on the life of a college student. One thing that always seems to be at college parties is alcohol. I have often heard someone complain that a party is lame because alcohol is not being served. I don’t want to sit here and talk about how alcohol is bad for you and you should never imbibe. That would be hypocritical of me since I drink, but I drink responsibly. Instead, I want to focus mainly on the microbiology and biochemistry of alcohol production. Have you ever wondered how alcohol is made or what happens to our bodies when we consume alcohol?
The answers to those questions will be revealed here, but before that, we need a little history - the briefest history lesson ever, I promise.
The process of making alcohol has been around since the early nineteenth century. However, brewers did not understand the chemistry or biology of the process until much later. Today, the average person will tell you that alcohol is made by yeast through the process of fermentation. But in the early nineteenth century, the existence of microorganisms was a matter of debate. It wasn't until the last quarter of the nineteenth century that people began to accept that microbes exist. Still, the process of fermentation wouldn’t be further explored until the twentieth century with the help of a great scientist, Louis Pasteur.
The Process of Fermentation
The type of fermentation used in alcohol production is appropriately named alcohol fermentation. It is also referred to as ethanol fermentation since ethanol can be a byproduct of the process. Yeasts are the most common microorganisms to carrry out this process, which involves the conversion of sugars, from things like grapes, grain starches, or sugarcane, into cellular energy (ATP), gases (like carbon dioxide), alcohols (like ethanol), and/or organic acids (like lactate). Different sugar sources yield different alcohol products. For example, the fermentation of sugars from grapes will produce wine, and the fermentation of sugarcane can produce rum. Fermentation is considered an anaerobic process, which means that this process is performed in the absence of oxygen; therefore, the tricky part of alcohol fermentation is letting the carbon dioxide out, but keeping the outside air from coming in.
The Reason Alcohol Makes Us Feel Good
The thing about ethanol is that it is water soluble and therefore can enter easily into the blood stream. However, it is the liver's job to metabolize ethanol. The liver accomplishes this by producing an enzyme called alcohol dehydrogenase. This enzyme metabolizes ethanol to acetaldehyde, which gets further metabolized to acetate and ultimately, acetyl-CoA. The problem is that the liver can only metabolize a certain amount of alcohol. The golden rule is that one drink takes about an hour to metabolize. When the liver is overburdened, the ethanol in the blood will build up and start going to all parts of the body including the brain. When ethanol has reached the brain, that’s when the fun starts. It binds to certain brain receptors, which either facilitates or inhibits other systems. By directly affecting these systems, alchol consumption indirectly affects other neurotransmitters and neuropeptide systems. It’s a big chain reaction that in the end affects motor skills, speech, and the ability to reason. This is the process that will in effect make a person drunk.
An Interesting Story
A 61-year-old man walked into an emergency room with a blood alcohol concentration that was five times his state’s legal driving limit. The interesting thing though is that the man didn’t drink any alcohol that day. The cause of his intoxication was a microbe in his gut. Apparently, the man had gotten infected by a yeast, which created a little brewery in his gut. So the man would randomly get drunk without even drinking. This is known as auto-brewery syndrome and is a very rare condition. He was cured of his disease by being treated with antifungal medication and a low-carb diet.
Overall, alcohol is an enjoyable substance that can be fun in a recreational setting. However, overdrinking and alcohol abuse can led to some serious problems. Films, television, literature, and social media often portray alcohol as an essential party item especially in college. If people do decide to go out and drink, they should remember to drink responsibly and to always have a designated driver.
This entry is part of the fall MICR 354 scientific writing students' blog series.
Pasteur Image: Nadar.
Fermentation Must Image: Agne27.