June 4 2020

Sterile Algae Transfer With Minimal Equipment

Curious how to do sterile algae transfer with minimal equipment?


Watch one of our plankton biologists show you how!

The Industrial Plankton PBR 100L and 1250L are great for growing algae in a biosecure way.  But the algae in the PBR is only as clean as the algae you put into it.

In this video we will demonstrate some of the basic principles of sterile technique.  We’ll be showing you how to transfer algae to a new 250 mL flask, but the principals are the same whether you are working with 50 mL tubes, 20 L carboys or the 1250L PBR!

To transfer your algae you will need an empty workspace, sterile culture media, your parent culture, a sterile empty flask, alcohol spray, a flame source, paper towel, gloves,  labels and a pen, and a lighter. Lab coat and Gloves are optional for this procedure.

However, One of the sources of contamination for algae cultures is you!  To minimize the chance of contaminating your cultures, put on a clean lab coat, pull your hair back, and put on a clean pair of gloves.

Prepare your workspace

Ideally, cultures should be transferred in a laminar flow hood, transfer cabinet or clean room to minimize contamination from the surrounding environment.  If none of these options are available do your best by choosing a bench away from foot traffic and airflow and then cleaning it. 

First, we’ll use the paper towel and alcohol spray to clean our empty workbench and wipe it down. Wipe the bench from back to front, so you clean the areas you were leaning over. You aren’t trying to dry the alcohol, but you want to spread it out so that the entire surface is cleaned. 

Once your workspace is clean

Use the alcohol spray to sterilize your hands and wipe down the outside of your sterile culture media, sterile empty flask, and your parent culture, with a paper towel sprayed with alcohol.

Next, light your flame source, but first, be sure you keep any fire sources away from your alcohol and make sure to wait until all of the alcohol has evaporated prior to putting hands near an open flame.     

Remember, before opening any sterile containers, resterilize your hands (gloved or not) with alcohol after touching any non-sterile surface (such as a lighter).  Remember to resterilize your hands (gloved or now) with alcohol after touching any non-sterile surface before proceeding.

Sterile Media

Now that your workspace is prepared, go and get your sterile media (we’re using f/2 here), your sterile flask for your new culture, and your parent/inoculum culture.  Next, we’re going to add sterile media to our new flask.  If you have sterilized your media inside your new flask, you have already done this step!  

  • Start by loosening the cap on your media bottle and next, remove the cap and stopper from your flask. 
  • Once removed, flame the opening . Place the flask close to the flame, and be careful not to move anything above it’s open mouth. Set the flask down and then open the media bottle.
  • Before we pour the media into the flask, we want to flame the opening of our media bottle as well.
  • Pour media from the bottle into the new flask, without touching the media bottle to the flask. Don’t worry if you spill, it is better to lose some media than risk contaminating the whole bottle. Make sure that you do not overfill the flask as it will be hard to flame the mouth later.
  • As soon as you are finished, flame the mouth of the media bottle again, cap it, and set it aside. Now, your new flask is ready to be inoculated.
Next we will get our parent culture

Take your parent culture, remove the cap and stopper and then flame the opening. It is important to avoid touching the stoppers to any surfaces so that they remain clean. Then pour a small amount into the new flask without touching. Next, Flame the openings of both flasks, replace the caps and stoppers, and return them to your culture chamber.

Now we will label our new culture vessel. If transferring more than one species at a time, it is especially important to label your flasks before any transfers. Labels should include the species name and strain number, the type of media, the date, and your initials. 

Now you have an introduction to the basic sterile transfer of algae cultures. Remember that proper cleaning and sterilization of equipment, minimizing sources of contamination, and minimizing the time sterile containers are open goes a long ways towards growing clean algae.  


For more videos like this, be sure to check out our YouTube Channel.

If you would like to learn more about our line of algae bioreactors, visit our Product page.