Study of Harvesting and lipid extraction

1. Algae
Term 4 Plan

2. Summary of term 2 and 3
We stepped up the number of big
jars we are growing on our mason
jar shelf. We now have two large
mason jars, two small mason jars,
and one big pitcher.
We have been looking further into
harvesting methods. We tried one
method (coffee filters and french
press), and that did not work. There
is not enough algae mass yet in our
bottles
We built a bioreactor out of poland
spring bottles on a metal shelf. The
idea behind the bioreactor is that it
will grow algae faster for us to
harvest. So far we have had some
problems with the air pumps.

3. What?
We will spend the fourth term researching and experimenting with the following
aspects of algae:
Brian: explore/compare harvesting methods to find one that is suitable for
greengineering (easy, quick, repeatable, thorough)
Ariel: explore/compare lipid extraction methods to find one that is suitable for
greengineering (easy, quick, repeatable, thorough)
Anna: Research the health trend of consuming algae and explore its
medical+nutritional benefits

4. So what?
Algae is a SUPER ORGANISM!!!!!!
its photosynthetic efficiency is higher than many other highly efficient crops
it is extremely efficient to grow
it contains proportionally high levels of lipids
more lipids can be extracted from a smaller amount of mass
it is a green answer to the fossil fuel problem
if production methods could become cheaper and more efficient, algae could replace oil as the fuel
of the future

5. Now What?
Individual plans/tasks:

6. Harvesting Algae – Brian
Algae is microscopic– chlorella cells are typically 2-10 micrometers in diameter
That makes algae very hard to remove from its medium!
Source 4
for reference, a human
hair is typically 50-70
micrometers
Source 5

7. Centrifugation
The most widely used and effective method
uses a centrifuge to separate algae from its
medium. Centrifuges are machines that spin
at very high speeds to separate substances
of different densities. Almost all types of
microalgae can be easily and effectively
separated using centrifugation. (source 2)
Source 6

8. Centrifugation in Greengineering
Unfortunately, centrifuges are very expensive
and only offer capacities of less than 100mL for
the most part, meaning centrifuges will not work
for our scale or budget.
It is possible, however, to create the same effect
of a centrifuge using materials found around the
shop. Here is one idea I am planning on trying as
a homemade centrifuge: Source 7

9. Sedimentation
the process by which gravity causes particles to separate from a liquid
the algae would sink down to the bottom of the jar, as Chlorella is denser than
water
it would take approximately 2 days for our algae to fully separate and sink to the
bottom
this method is extremely low cost but usually yields lower densities and further
water removal is usually required
the hard part is removing the algae from the bottom of the container

10. Removal of Algae
one method to easily remove the algae after
the sedimentation process is to use a
container with a cone-shaped bottom, so
that the algae sinks far into the cone and
the water can be slowly poured out of the
top of the container
this is definitely something I can try with
readily available materials in the
greengineering room Source 7

11. Flocculation
the process of sedimentation can
be accelerated using a technique
called flocculation, where
chemicals are added to the medium
to cause the algae to group up into
big clumps that sink to the bottom
much quicker, in as little as 20
minutes
(source 2)
this extra step will make our algae more
accessible and help us achieve a higher
density yield
Source 10

12. Flocculation in Greengineering
chemical flocculants such as Lime (calcium
hydroxide), ferric chloride, and aluminum chloride
have been commonly used to remove algae from
wastewater (source 2)
Lime is the most easily accessible out of these three,
so I plan on adding small amounts of Lime to our
algae before it is harvested to see how much it can
improve our yield
Lime is caustic and can cause burning so safety
measures will have to be taken
Source 11

13. Filtration
As explained before, algae is
extremely tiny and therefore
is very difficult to catch with
filters. Filtration is possible,
however, using specially
designed micro filters which
are classified by pore size, so
we could purchase filters with
pores to catch Chlorella.
Source 2
Drawbacks to filtration:
relatively slow/low throughput
requires pressure to force liquid through
filter, which can use quite a bit of energy
energy required increases as the pore size gets
smaller, but good news!– while a pore size of
less than 1.5 micrometers is needed to catch
normal algae, you only need a pore size of 25
micrometers to catch flocculated algae!
filters can clog quickly

14. Goal
compare the feasibility of all these methods in the greengineering classroom and
choose one that best suits our needs to further develop
Criteria:
efficiency (time and energy)
effectiveness (density of yield)
capacity (the more volume we can process the better)
cost (we have no money)

15. Lipid Extraction- Ariel
http://journal.frontiersin.org/article/10.3389/fenrg.2014.00061/full
Lipid extraction is a crucial step in algae biofuel production:
Determines the overall biofuel yield of the conversion process
Can make or break the project as a whole
Dictates the efficiency of the conversion process based on the variables of the extraction process
The 4 main variables of the extraction
Cost
Time

16. Lipid Extraction (continued)
Our Goal for the Lipid Extraction Process:
Find the most efficient extraction method, NOT the one that produces the most
yield:
Not feasible in the real world
Can result in net energy loss

17. Lipid Extraction (continued)
Two primary extraction pathways:
Physical
Chemical
To achieve the highest yield, using both a chemical and physical process together is usually more
effective however can be less efficient depending on the chosen methods.
The ultimate goal of any extraction method is to rupture or penetrate the cell wall
of the algae cell to leak out the lipids inside.
Let’s look at the possible options for lipid extraction methods!

18. Lipid Extraction (continued)
Organic Solvent Method: chloroform, methanol, ether, hexane
Efficiency rating: Moderate
Cost: Relatively high due to to solvent costs, recycling solvents is an option but is
an energy intensive and timely process
Energy cost: Energy intensive
Other remarks: Health hazards and waste management issues due to chemical
supply.

19. Lipid Extraction (continued)
Expeller Press Method
Efficiency Rating: low to moderate
Cost: High due to high costs of industrial grade expeller presses
Energy Cost: Energy intensive, press runs on electricity

20. Lipid Extraction (continued)
Osmotic Shock Method
Efficiency Rating: Moderate to high
Cost: Low
Energy Cost: Low
Remarks: Process requires lots of time

21. Lipid Extraction (continued)
Our plan: Extraction through Osmotic Shock
Osmotic Shock is the most energy efficient, the cheapest, and gives the best yield
of the 3 methods listed.
There are many more methods, however they aren’t feasible for the purpose of
this class in terms of efficiency, cost, and training.
This method harnesses the power of hyper-osmotic stress and osmotic shock to
rupture the cell wall.

22. Algae for food- Anna

23. Overview of Spirulina and Chlorella
Similar to chlorella (the algae we have been growing), spirulina is a blue-green
freshwater algae.
Spirulina is multi-celled and contains protein, vitamins, minerals, and antioxidants.
It contains nutrients such as B complex vitamins, beta-carotene, vitamin E,
manganese, zinc, copper, iron, selenium, and gamma linolenic acid
Chlorella contains protein, vitamin A, Vitamin B2, Vitamin B3, Iron, Magnesium,
and Zinc.
Differences: chlorella has a stronger cell wall making it harder and more
expensive to break down, chlorella has more chlorophyll, and c

24. Health Benefits
Like most health supplements, spirulina and chlorella contain high concentrations
of protein, vitamins, and minerals, so it can help people reach their daily intake
Spirulina is a natural antihistamine- it helps with allergies
Spirulina has been observed to have a hypolipidemic effect which means it can
lower people’s cholesterol
One study reported Spirulina as helping people with cardiovascular conditions
Spirulina can help regulate the metabolism

25. What I am doing now+Fun Facts
I bought chlorella pills online, and I am going to see if I notice any changes to my
wellness
Hopefully, this will be a more sustainable way to get my protein
Fun Facts:
Spirulina was eaten by the Mayans and many other Indigenous tribes native to
Central America
There is an international coalition for the use of microalgae against malnutrition
that was launched in the 70’s to help combat famine

26. End of Term 4
We will create an “Algae Roadmap” that will outline the steps needed to recreate
everything we accomplished this year. This way future groups will be able to use our
research to quickly get algae growing instead of having to go through all the
struggles on their own. Groups will have more time to focus on the various areas of
algae they want to explore.

27. Bibliography
Source
1. https://www.nature.com/articles/srep40725
2. Milledge JJ and Heaven S (2013) A review of the harvesting of micro-algae for biofuel production
3. Wikipedia.org
4. http://www.algaeindustrymagazine.com/wp-content/uploads/4.Chlorella.jpg
5. https://cdn.shopify.com/s/files/1/1074/7010/products/tresse-bang-_60-1_14881eed-90b6-4af6-97ba-24034231c965.jpg?v=1448918698
6. http://i.ebayimg.com/00/s/NTY2WDg0OQ==/z/B7EAAOSw~gRV6WUj/$_32.JPG?set_id=880000500F
7. http://www.biodieseldiscussion.com/forums/showthread.php?t=28591
8. https://algaebiodiesel.wikispaces.com/file/view/Floctation.png/274023864/Floctation.png
9. https://www.sciencecompany.com/Assets/ProductImages/nc8606n.jpg