Lecture 17 Flashcards

1
Q

When did algae form

A

1.8 billion years ago (in the Proterozoic Eon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What allowed early eukaryotic cells to harvest light energy

A

Incorporation of photosynthetic cyanobacteria (endosymbiotic theory)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What helped generate the oxygen levels needed for life to emerge

A

Cyanobacteria and algae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Do algae use photosynthesis

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Algae photosynthesis

A

Use photosynthesis to generate organic carbon from CO2 and the energy of light (O2 is a byproduct)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Can algae produce lipids/oils

A

Yes, under certain conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What percent of their dry weight can algae produce in oil

A

70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Other compounds that can be produced by algae

A

Butanol, hydrogen, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Genera common for bioenergy purposes

A

Chlorella
Botryococcus
Dunaliella
Nannochloropsis
Scenedesmus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Growth conditions that algae can have

A

Phototrophic
Heterotrophic
Mixotrophic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Phototrophic growth

A

Requires light energy and inorganic carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Heterotrophic growth

A

Requires an organic carbon source for energy (e.g. glucose, glycerol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mixotrophic growth

A

Combination of light energy, organic carbon, and inorganic carbon (rarely used)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Nutrients required by algae

A

Nitrates, phosphates, potassium, calcium, zinc, iron, magnesium, manganese, molybdenum, copper, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why is it so expensive to grow algae for biodiesel

A

The need for nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Strategy to keep the cost low for algae biodiesel

A

Use of human wastewater as a source of nutrients

17
Q

Requirements of algaeal farms

A

Sunlight
Carbon dioxide
Moderate temperatures
Water
Nutrients
Land
The appropriate algael strain

18
Q

Main types of algael farms

A

Open
Closed

19
Q

Types of open system farms

A

Ponds
Raceways

20
Q

Downside to open system farms

A

Less control of nearly every parameter

21
Q

What type of system is more expensive to build and operate: open or closed?

22
Q

Main types of closed system farms

A

Columns
Tubes

23
Q

Control over closed system

A

Great control over parameters

24
Q

What does the choice between open and closed systems usually come down to

A

How much you have to invest

25
Harvesting
Separating mature algae from water
26
Harvesting methods
Centrifugation Flocculation Sedimentation Filtration
27
Centrifugation
Spinning at high speeds
28
Flocculation
Algae aggregate and clump (auto and induced)
29
Sedimentation
Gravity will cause algae to settle over time
30
Filtration
Use fine screens to separate algae from the water
31
Physical extraction of lipids from algae methods
Mechanical disruption Electric pulse Sonication Osmotic shock Expeller press
32
Chemical and biochemical extraction of lipids from algae methods
Solvent (hexane) Enzymatic
33
Algae produces ____ that can be used to make biodiesel
Triacylglycerides
34
___ of algal lipids leads to FAMEs
Transesterification
35
Is the overall process of algae biodiesel production affordable
No
36
Cost per gallon of algae diesel
$8 per gallon