Biofuel

Question 1

What are the four generations of biofuels?

Answer 1

1st gen: cereal and sugar crops; 2nd gen: lignocellulosic feedstocks; 3rd gen: microalgae; 4th gen: genetically engineered microalgae and cyanobacteria

Question 2

What is bioethanol primarily derived from?

Answer 2

Glucose from biomass (plants or algae)

Question 3

What process is used to convert glucose into ethanol?

Answer 3

Fermentation

Question 4

Fill in the blank: The first generation of biofuels is capped due to the competition between ______ and fuel.

Answer 4

food

Question 5

What must plant biomass undergo to produce glucose?

Answer 5

Breakdown

Question 6

What are the two methods for breaking down cellulose?

Answer 6

• Chemical (acid)
• Biological (cellulases)

Question 7

What type of feedstock is used in the second generation of biofuels?

Answer 7

Lignocellulosic feedstocks, e.g., energy crops and agricultural waste

Question 8

What organism is used for 2-butanol production?

Answer 8

Klebsiella pneumoniae

Question 9

What is an advantage of 2-butanol over ethanol?

Answer 9

Higher energy density & lower hygroscopicity

Question 10

Which enzyme from Lactobacillus brevis is used for diol production?

Answer 10

Diol dehydratase (pduCDEGH)

Question 11

What is the effect of knocking out ldhA in K. pneumoniae?

Answer 11

Increases 2-butanol production to 480 mg/L

Question 12

What is the role of B12 in the conversion of 2,3-butanediol to 2-butanone?

Answer 12

Required for diol dehydratase activity

Question 13

Which cyanobacteria can be genetically manipulated to produce biofuels?

Answer 13

Synechocystis sp. & Synechococcus sp.

Question 14

What pathways are engineered in cyanobacteria to produce ethanol?

Answer 14

Pyruvate decarboxylases & alcohol dehydrogenase pathways from Zymomonas mobilis

Question 15

What are the three modes of fermentation?

Answer 15

• Batch
• Continuous
• Fed-batch

Question 16

What is a characteristic of batch fermentation?

Answer 16

Closed system with limited nutrient concentration

Question 17

True or False: Continuous culture is used for metabolite production.

Answer 17

False

Question 18

What is the purpose of fed-batch fermentation?

Answer 18

Maintains limiting substrate at low level and controls growth rate

Question 19

What are key properties of a fermentor?

Answer 19

• High concentration of biomass
• Sterile
• Efficient power consumption
• Effective agitation
• Ease of cooling
• Convenient sampling

Question 20

What type of fermentor is classified by gas distribution?

Answer 20

Aerobic fermentors

Question 21

What is a common method for controlling excessive foaming in fermentation?

Answer 21

Anti-foaming agents (e.g., vegetable oils)

Question 22

What can lead to loss of productivity in fermentation?

Answer 22

Contamination

Question 23

What is the common method for medium sterilization?

Answer 23

Steam sterilization

Question 24

Who discovered penicillin?

Answer 24

Alexander Fleming

Question 25

What is the source of penicillin production in fermentation?

Answer 25

Penicillium chrysogenum

Question 26

What is the temperature range for penicillin production?

Answer 26

25-27 degrees Celsius

Question 27

What is the process of recovering penicillin crystals?

Answer 27

Filtration, crystal washing, vacuum tray drier

Question 28

Fill in the blank: Penicillin fermentation uses a _______ fermentation method.

Answer 28

Fed-batch

Question 29

Which alcohol dehydrogenase is transfected into K. pneumoniae?

Answer 29

Adh from Clostridium autoethanogenum