Lecture: Pumice stones to fade jeans: Narrator: Listen to part of a lecture in a fabric design class. Professor: What are enzymes is myself a question about this have to do your assigned reading. Enzymes are really catalyst – chemicals used to get the reaction going. If you think about the humanbody, the humanbody temperature is really not high enough to make the action happen. So that's why there are enzymes to make certain reactions happen. If you think about the digestive system, it has enzymes that help break down food. An enzyme in our saliva breaks down carbohydrates, sugars, and starches. And in the stomach and small intestine, we have enzymes that break down proteins and fats, in addition to carbohydrates. These enzymes are substances like lactase, you might have heard of that one, lactase is the milk enzyme, and it breaks down lactose, the sugar in milk. But today let's look at mousses of enzymes in our industry. For instance, as I look around the room, I see many of you are wearing faded jeans, you know, companies with enzymes to stage a jean? They use an enzyme called cellulase to create that faded denim. But we didn't always use cellulase. Well, we didn't always have said a jean drive it. Back in the day when you bought your jeans, they were a nice dark blue. It was only after many washing that they would get that faded yet. It's only in the 1970s that companies realized there was a market for genes that already looks faded. So companies started to create their jeans. Anyway in the 1970s and 80s, the pumice stones were used in a process called stone-washing. What would happen? The textile companies will put pumice stones and ... uh, what is pumice stone? It's a volcanic stone. It's very light. It actually floats on water, but rough. And it is grounded up and used including products like heavy duty hand shows. So these pumice stones would then, as I said, be put into a big washing machine and the jeans would be washed with stones. Well, as you can imagine, when the process was finished, the washing machine was just about worn out, and the jeans would look faded, but also a worn out too, because the pumice stones would have grade some areas more than other areas. Other things that would happen, or the buttons on denim jacket or the rivets on the pockets would have a worn-nut finish. But you want your buttons to be shining, and you want a rivets to look shining too. Right? Well, so that process didn't work very well. There was another problem, but I'll get to that in a minute. Next, the textile industry moved on acid-washing. They used acidic bleach, something stronger than you use at home. And the bleach would break down the fibers and make the dye fade. You can imagine the damage here. Employees were exposed to acid, and it was not an environmentally safe process. Environmental protection agency, a government agency, would monitor the waste water that came from the company and when they found this acid in the stones. And I guess this is that, uh, other problems with stone washing I mentioned. When they found these things in the waste water, that was not good, because the agency would enforce anti-pollution laws and require the company to pay to clean up the water. So that added to the company's expenses and the cost of the jeans. Finally, in 1989, the textile industry in Europe discovered what they called bio-stone. That's the name they gave to the process of using cellulase to fade denim. Cellulase is the enzyme that breaks down cellulose, just like the lactase breaks down lactose. Jeans are made of denim, type of cotton fabric and can't be a plant contains uh contains cellulose and that's why they use cellulase. Um, it's still a washing process just using cellulase instead of stones or acid. Using the cellulase creating more even and consistent finish on the denim without streaks of blocks like you get in the other process and it's gentler. It doesn't wear out the denim that much. So you have a nice looking pair of pants that doesn't cost the company a lot of money to make. Also schedule a treatment or less polluting than either stone washing or acid washing, at least according to manufacturers, another nice benefit, don't you think?