1. Biotechnology

2. Objectives Explain how biotechnology has improved the process of making cheese

3. Terminology Rennin Chymosin (Chy-max) Curds Whey

4. Cheese-Making Technology Cheese-making- Originally achieved by letting naturally occurring bacteria turn the milk sour

5. Milk bacteria have enzymes that convert the sugar lactose to lactic acid. Lactic acid has an acidic pH At a low pH, the milk protein, casein, breaks down or denature Also the proteases found in the bacteria act like scissors and cut the casein into smaller fragments The denatured casein forms the solids observed in sour milk How cheese is made

6. The solids are curds Curds are pressed together to form cheese The left over liquid is known as the whey How cheese is made Curds from sour milk

7. Which Curdling Agent worked the Best? Speculate as to why?

8. Milk Culture was 1:5 ratio of buttermilk to whole milk Why buttermilk added to the milk? Buttermilk has an active culture of Lactobacillus bacteria that can act as starter for curdling milk

9. Curdling Agents – What makes them different? Rennin – purified protease from cow’s stomach that cleaves the milk protein casein into smaller fragments that settle out as curds Chy-max –Rennin genetically engineered to be made in Fungi. Fungi produce the enzyme faster and in larger amounts than a cow can make.

10. Genetic Engineering of Chymosin

11. Think-Pair-Share Why would the production of chymosin be advantagous for the cheese-maker? 3

12. Industrial process of making cheese Video on cheese-making

13. 13 Minute Paper You have one minute to write down how cheese making is an application of biotechnology. Be prepared to share.