Glycolysis and Cellular Respiration
In the Real World
History and Glycolysis and Cellular Respiration
Fermentation is not only a biological process, but a critical component of making alcohol and bread. Cultures around the world and throughout history have used fermentation to produce beer, wine and bread.
We already learned that alcohol fermentation, done by bacteria and yeast, produces ethanol, which is alcohol, and carbon dioxide. The carbon dioxide makes bubbles, which makes beer frothy, and causes bread to rise. Some would even say beer is the most important invention in the world—watch How Beer Saved the World for more details.
Human use of fermentation goes way back—ancient civilizations made alcohol, as early as nine thousand years ago in Neolithic China (Dietler 2006). The ancient Sumerians made beer (Michel and Patrick 1992), and some researchers even think that beer is why we have civilization at all. Back in the day, humans lived nomadic lives, roaming around to hunt. About 10,000 years ago, they started settling down and grew crops, domesticated animals (really cut back on the need for orange hunting vests), and lived in cities and villages. Some researchers believe humans started growing crops so that they could make fermented beverages from them. One of the first crops grown during the agricultural revolution was barley. Since beer is made from barley, anyone who wanted to brew (and drink) beer would have to grow the barley first. Then they had to stick around to brew the beer. Ancient people said goodbye to their previously nomadic lives, planted barley, and became the first farmers and brewers. The first brewers probably stumbled upon beer by accident, but they quickly figured out how to keep making it, and today brewing is down to a science.
Archaeologists can tell that certain pots used to hold beer because of a residue they find on artifacts. In ancient Mesopotamia, evidence suggests that the wealthy elite drank wine and lower classes drank beer. This is not so surprising, since water was not purified and beer was probably safer to drink. In both ancient and modern societies, wine and other alcoholic beverages are integral parts of ceremonies and rituals (Dietler 2006). Before water purification and refrigeration, it was probably useful to have a beverage around that would keep for awhile.
Alcohol was vital to ancient Greek and Roman societies, not just as an intoxicant, but also as an important economic commodity. The Romans shipped huge quantities of wine to their colonies. In the 1700s, alcohol was an important trade item to the colonial powers participating in the West African slave trade. Rum, made from sugar cane, was traded for slaves, who were then forced to work on those very same sugar plantations (Dietler 2006).
Humans are not the only ones who enjoy fermented products. Lots of other animals ingest ethanol when they eat ripe fruit. Fruit growing in the tropics, with the warm and wet climates there, is especially prone to hosting fermenting yeast. Many tropical fruits contain low levels of ethanol, so animals that eat large quantities of fruit are also steadily taking in alcohol (Dudley 2002). The alcohol content of fruit adds more calories, and therefore more nutrition, to the fruit (to animals living in the wild that have to search for food all day, the more calories, the better). In fact, the fruit-eating patterns of our primate ancestors and the high-calorie rewards from ethanol-laden fruit may provide the evolutionary basis for human alcoholism (Dudley 2000, 2002).
That is enough about alcohol…on to a more important thing: bread. Bread is another major product from fermentation. A world without bread would be like a day without sunshine. Bread has had a pretty big impact on world history. After all, didn't the French Revolution start because people had to wait in long lines for their baguettes? Hmm…maybe it is time to go back and read A Tale of Two Cities.
The ancient Sumerians started making bread around 6000 BC (Belderok 2000). Although grains had been cooked before, it was around then that people actually made leavened bread—bread that has yeast in it, causing it to rise. Compare a tortilla to a loaf of bread and you can easily see the difference.
Three thousand years after the invention of bread, the Egyptians really made heated things up by inventing ovens to bake bread (Belderok 2000). In Europe, wheat was not originally the preferred grain—barley was most popular, probably because of its use to beer making. In the Middle Ages, rye became very popular, and finally in the 1700s wheat was the basis of most breads.
The old school way of harvesting wheat:
Bread, like alcohol, became a staple to human diets and economies. Wheat and rye were traded in large quantities in Europe as the population grew quickly in the 1200s. So much of these grains went through Amsterdam that it became known as the "Granary of Europe" (Belderok 2000). In the late 1700s, the center of grain production for Europe shifted away from Amsterdam to Russia and the up-and-coming American economy. Wheat production grew very rapidly in the U.S. and Canada, supplying grain for an exponentially growing world population. Of course, farm and transportation technology were influenced by the need to grow and transport large quantities of wheat. So it might not be such a stretch to say our modern railroads and interstates owe their existence to alcohol fermentation.
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