Enzymes in Nature
Enzymes are one of the most interesting and important substances found in nature. Firts, it's important to realize that enzymes are not living things. They are inanimate - like minerals. But unlike minerals, they are made by living cells. If we were to look inside a cell we would see many different activities going on. There would be some molecules joining together and others breaking apart. These activities keep the cell alive and enzymes make these activities possible. That's why every cell of every living creature on Earth produces enzymes.
In a broad sense, there are two types of enzyme. Some that help join specific molecules together to form new molecules. Others that help break specific molecules apart into separate molecules. Enzymes play many important roles ouside the cell as well. One of the best examples of this is the digestive system. For instance, it is enzymes in your digestive system that break food down in your digestive system break food down into small molecules that can be absorbed by the body. Some enzymes in your digestive system break down starch, some proteins and others break down fats.
Four things to remember about enzymes
1. Enzymes are specific: An enzyme that is able to break fat down would not be able to dissolve protein or starch. Enzymes perform only one specific job. That means an enzyme can do its job with very few side effects. It also explains why there are so many different types of enzyme. To date, 3,000 different types have been identified and there are many more waiting to be discovered.
2. Enzymes are catalysts: While it is true that an enzyme can only perform one speific job, it is important to know that one enzyme can perform that same job over and over again, millions of times, without being consumed in the process. And enzymes do their job best in the mild ph and temperature conditions found in nature.
3. Enzymes are efficient: Not only do enzymes work hard, they also work with blinding speed. For instance, there is an enzyme in the liver that helps hydrogern peroxide break down into water and oxygen. What's amazing is that one enzyme can process 5 million hydrogen peroxide molecules in one minute.
4. Enzymes are natural: Enzymes are proteins. Like all other proteins, enzymes are organic. Once they have done their job, enzymes break down swiftly and can be absorbed back into nature.
Enzymes in Industry
Many people believe enzyme technology is fairly new. However, that's not the case. Enzymes have been used by man from the dawn of civilization. As long as people have been eating bread and cheese, and drinking wine and beer - they have been using enzymes. That's because enzymes help to make these products.
Take cheese for example. Most likely, cheese was discovered by ancient hunters who stored milk in the stomachs of slaughtered calves. When exposed to heat, the milk inside the container would turn into a solid - cheese. The reason for this is simple. Calves have an enzyme called chymosin in their stomachs. At ambient temperature chymosin will break down milk protein, causing milk to separate into curd and whey. If you strain away the watery whey you are left with a soft tangy curd or cheese. Chymosin derived from calf stomachs has been used in cheese making ever since.
In more recent times, other commercial uses for enzymes have been found. Laundry detergents are a good example. As mentioned, there are certain enzymes which dissolve proteins and others which dissolve fat. Proteins and fat make up two of the major causes of stains on cloting. Grass, blood and egg are all protein stains. Lipstick, frying oil, butter, sauces, and tough stains on cuffs and collars are fat stains. to remove these stains without enzymes is difficult and requires a lot of washing at high temperatures with a lot of detergent.
Enzymes can remove these stains better, faster and in a way that is a lot kinder to the clothing and the environment. The enzymes in detergent dissolve stains in the same natural way they help digest food in your stomach - specifically and efficintly. Just a tiny amount of enzymes can dissolve stains that would require much larger amounts of detergent alone. Because of this they can reduce the amount of detergent actually found in laundry detergent. And since enzymes work best in mild conditions, washing machines using enzymatic detergants can be set at lower tempreatures, reducing electricity consumption by as much as a third. In the future, enzymes could replace more and more of the harsh chemicals found in detergents.
Many other industries
These two examples represent just the tip of the iceberg. Enzymes are contributing to industry in many other areas. They are starting to replace petroleum-based solvents used to make vegetable seed oil; replacing harsh acids used in the production of glucose products such as corn syrup; taking over part of the role played by clorine in the paper industry; and replacing sulphides used in the tanning industry. Enzymes are also being used instead of pumice stones in the stonewashing of jeans.
Enzymes help industry and nature
Today enzymes are helping industry make the products used by society in a way that is less harmful to the environment. In the cases mentioned above, enzymatic processes are, in general, safer and more environment-friendly than the traditional processes they replace. That is why enzymes in particular and biotechnology in general hold such promise.
How Enzymes are Produced
Looking back to the cheese example above, chymosin is an enzyme used to turn milk into cheese. And chymosin is only found in the stomachs of young calves (as well as young sheep, goats, and a few other farm animals). Up until the 60s all the world's cheese was made from chymosin extracted from the stomachs of slaughtered calves. Then two things happened. The demand for cheese increased and the demand for alf meat decreased. Soon there were not enough slaughtered calf stomachs to produce enough high-quality chymosin required by the expanding cheese industry. To solve the chymosin shortage, it would have been very wasteful and very expensive to raise and slaughter calves just to extract a relatively small amount of chymosin from their stomachs. The cheese industry and the enzyme researchers began to look for another type of organism that produced chymosin.
Microorganisms are natural enzyme factories
The researchers wanted to find an organism that was easier and less expensive to raise than a calf. An organism that reproduced quickly and wouldn't require a lot of space and food. So they began looking among the smallest and simplest organisms they knew: micoorganisms. Microorganisms are very small living organisms. Some examples are bacteria, fungi and yeast. They live in soil or water in every corner of the earth. Because they are so small, they are obviously a lot less complex than a calf. Even so, a simple microorganism can produce many different types of enzyme. In fact, it doesn't take a complex organism to create a complex enzyme - as was proved by a simple fungus named Mucor. This fungus produced a chymosin-like enzyme that was almost the same as that produced by calves. But finding the right enzyme is only half the battle.
Microorganisms often aren't suited for "life on the farm"
Once identified a microorganism needs to be "farmed" in a controlled setting. Most microorganisms can grow and multiply quite well in liquid. So large tanks are used called fermentation tanks to grow microorganisms. Ideally, a microorganism will grow fast and produce a lot of the desired enzyme at mild temperatures consuming inexpensive nutrients. But like most things in life, the ideal microorganism is hard to come by.
As it is, most microorganisms found in the wild are not so well suited for domestication in fermentation tanks. Some only produce tiny quantities of the desired enzyme, or they may produce undesirable by-products, or take a long time to grow, or require a growth environment that is very difficult and expensive to maintain. The result is that although we often find ourselves with a microorganism that can produce the enzyme needed the cost for cultivating it is prohibitive. That's where genetic engineering can help