Lec 14: Metabolic Engineering

Question 1

ethanol

Answer 1

a 2-carbon alcohol

Question 2

Why do we want to bioengineer things like oil?

Answer 2

Many of the fuels and chemicals we use come from crude oil, which is not sustainable. Nations have gone to war over resources

Question 3

What are some of the pros and cons of biofuel and chemical production?

Answer 3

Pros: It is renewable.

Cons:
But there is a lot of energy lost to heat
It still costs more to make things using biofuel.
The things we use as biomass to feed the bacteria (ie corn, sugarcane) would otherwise be used for other things like cattle feed, so there is competition over those resources

Question 4

Fermentation to produce ethanol in anaerobic microbial growth:

Answer 4

Question 5

Describe the general e.coli fermentation pathway (mixed acid fermentation)

Answer 5

Question 6

Answer 6

Molar efficiency if the system is ideal:
1 mol Glucose –> 2 mol Pyruvate –> 2 mol ethanol

For mass efficiency, which is much lower, look at molecular weight of the two compounds

Question 7

What are some consideration when making the next-generation biofuels?

Answer 7

• high energy yield per liter
• make sure it doesn’t freeze in cold weather
• hygroscopicity: the tendency to attract water when it sits (which will then corrode things like pipes/fuel lines, etc)–why we can’t mix too much ethanol in with our fuel
• new fuels need to be compatible with existing infrastructure

Question 8

Artemisinin

Answer 8

the most potent drug against malaria–comes from a tree, from an old Chinese recipe. It is slow to produce, and so it’s hard to ramp up supply to meet the need during outbreaks. End ups with oscillating supplies and demands, and price fluctuations

Question 9

Challenges of producing Artemisinin

Answer 9

Need to make it cheaply, and not flood the market, so it’s very hard to make a profit manufacturing this