Title: 2.2 KSB II: Protease Production
Course: ATEP - Biotechnology Module B > Section: Section 2 Research and Investigate

2.2.1 KSB II: Protease Production

In KSBI, your team identified just one factor that could contribute to an organism growth. In KSB II, you will research several other conditions important for your organism's growth and ultimately production of protease. They are:

- Temperature
- Time
- pH
- Oxygen

As you move through this section, complete the worksheet titled: Knowledge and Skill Builder II: Reviewing Production Parameters for Protease that Could Affect the Design of the Bioreactor. You may need to return to Module A lessons or the Technology Park to review.

If you are not clear about an answer, use the internet to research. Generally, a website that ends in .edu, .org or .gov can be considered a valid source. Then check your research with your instructor.

This handout should be taped into your notebook.

2.2.2 Temperature

Microorganisms have varying requirements for temperature in terms of how much or how little they will grow. Most prefer body temperature, but others may require lower or higher temperature for optimal growth. If the temperature is too low, the bacteria may stop growing. If it is too high, the bacteria may die.

As you can see, the organism in the graph below will grow in temperatures between 15 degrees Celcius and 35 degrees Celcius, but the optimal temperature is around 32 degrees Celcius.

Research the optional temperature for your chosen organism and record this information in the KSBII handout.

2.2.3 Time

In ideal conditions, most bacteria will grow and multiply by dividing into two every 20 minutes. After 6 hours, in ideal conditions, one bacterial cell could become 131,072 bacteria. This time will vary based on the organism.

Below is a typical growth chart for microorganisms which consist of 4 phases: lag, log, stationary and  death.

Research these phases and decide when the optimal time to test for protease production should be. Record this information in KSBII.

2.2.4 pH

pH

All bacteria require a certain pH level, which can vary widely in the many different types of bacteria. Changing the pH level simply means adding or subtracting hydrogen ions. Adding an acid or a base to your medium can do this.

Changes in pH levels have the most noticeable effects on bacterial enzymes. Extreme changes in the pH balance of the media for bacteria tend to kill them, but some bacteria, like Lactobacillus, can handle highly acidic environments like that in the small intestines.

Research the optional pH for your chosen organism and record this information in the KSBII handout.

2.2.5 Atmospheric Gas

Maintaining optimal atmospheric gases is important in bacteria growth. Some bacteria require oxygen to live. Other are killed in its presence. Still others can live with or without oxygen using oxygen if present for maximum growth.

A simple aquarium pump can easily accomplish this task as well as aerate the sample to allow for optimal growth. The pump will increase media circulation and surface area for proper gas exchange.

Research the gas requirement for your chosen organism and record this information in the KSBII handout.