How to Turn Algae Into Biodiesel With a Blender

How to Turn Algae Into Biodiesel With a Blender

How to Turn Algae Into Biodiesel With a Blender


Turning algae into biodiesel at home is an exciting way to produce your own renewable fuel. Algae can be grown easily and its oils extracted to make biodiesel that can be used in any standard diesel engine. With some simple equipment like a blender and basic chemistry knowledge, you can make algae biodiesel right in your own kitchen.

Here’s a step-by-step guide on how to turn algae into biodiesel using a blender.

Growing the Algae

The first step is to grow your algal biomass. There are a few easy ways to cultivate algae at home:

Open Pond

This involves growing the algae in an open container filled with water. Sunlight and ambient CO2 will feed the algal growth. Place the container in a sunny spot and inoculate with an algal starter culture. Provide nutrients like nitrogen and phosphorus for optimal growth.

Aeration and mixing is needed to prevent settling. An aquarium pump connected to a air stone works well. Monitor and maintain proper pH and temperature. Harvest the algae when ready.


For better control, grow the algae in an enclosed photobioreactor. This can be as simple as a clear plastic bottle or glass jar. Agitate and aerate the culture with an aquarium pump. Use grow lights to replace sunlight if needed. Maintain ideal growth factors until the algae are ready for harvest.

Key Growing Tips

  • Stir or agitate the algae frequently
  • Ensure adequate CO2 and nutrients
  • Control pH between 7-9
  • Temperature around 20-30°C
  • Enough sunlight or grow lights
  • Avoid contamination

Harvesting the Algal Biomass

Once the algal culture has reached a dense concentration, it’s time to harvest. There are a couple harvesting methods:


Add a compound like chitosan to induce the algal cells to clump together into flocs. The algae can then be siphoned off or filtered out from the water. Centrifugation can also help concentrate the harvested algae.


Use filter paper, cloth, or a screen to filter out the algal biomass from the water. Cheesecloth works well for filtering small volumes. Scrape the thick algae paste off the filter for the next steps.


Spread the harvested algae onto sheets and allow it to dry in the sun for a few days. Turning it over periodically will help it dry faster. The dried algal flakes can then be used to extract oil.

Extracting Algae Oil

With the dried algal biomass, now it’s time to extract the oils. This can be done by:

Solvent Extraction

Dissolve the dried algae in a solvent like hexane or ethanol. The oil will dissolve in the solvent while the residues precipitate out. Distill off the solvent to recover the oil.


Use an oil press to squeeze the oils out of the algal biomass. A mustard seed press works for small batches. Heat and pressure helps liberate more oil.


Add some vegetable oil to the dried algae in a blender. Blend on high for several minutes to help rupture the cells and release the oils. Filter the slurry through a cheesecloth to separate the oil.

The crude algae oil now needs to go through a few more steps to become biodiesel.

Making Algae Biodiesel

With the extracted algae oils, we can produce biodiesel using transesterification. This uses methanol and a catalyst to convert the oils into biodiesel. Here’s how to do it:


For each 1 liter of algae oil you’ll need:

  • 200 ml methanol
  • 20 ml potassium hydroxide catalyst (20% solution)


  1. Mix the methanol and potassium hydroxide until dissolved.
  2. Add the algae oil to a blender.
  3. Pour the methanol/catalyst mix into the oil while blending.
  4. Continue blending for 2-3 minutes once mixed to complete reaction.
  5. Let settle overnight until it separates into biodiesel and glycerin layers.
  6. Pour off or siphon the clear biodiesel and wash with water to remove impurities.

And that’s it – you now have homebrew algae biodiesel made right in the blender! Just follow some safety precautions when handling methanol and lye.

Using Algae Biodiesel

The algae biodiesel can now be used to power any diesel engine. Here are some usage tips:

  • Can be used pure or blended with petrodiesel
  • Performs similar to fossil diesel
  • Compatible with any diesel engine without modifications
  • Reduces emissions compared to pure petrodiesel
  • Mixing with petrodiesel may be required in cold weather

So in summary, producing algae biodiesel with a simple blender is totally feasible. Just grow your algae, extract the oils, and mix up a biodiesel batch. You’ll have the satisfaction of making your own renewable fuel from start to finish!