How to do sterile algae transfer with minimal equipment?

The Industrial Plankton PBR 100L and 1250L are great for growing algae in a biosecure way.  But the algae in the PBR are 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 principles 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
• One Sterile empty flask
• Alcohol spray
• One flame source
• Paper towel
• Labels
• One pen
• Lighter
• Lab coat
• Gloves (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. Wipe the bench from back to front so you clean the areas where you were leaning. You aren’t trying to dry the alcohol; you want to spread it out so 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 before putting your 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 not) with alcohol after touching any non-sterile surface before proceeding.

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’ll add sterile media to our new flask.  If you have sterilized your media inside your new flask, you have already done this step!  

1. Start by loosening the cap on your media bottle, and next, remove the cap and stopper from your flask. 
2. Once removed, flame the opening. Place the flask close to the flame, and be careful not to move anything above its open mouth. Set the flask down and then open the media bottle.
3. Before we pour the media into the flask, we want to flame the opening of our media bottle as well.
4. 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 mouthpiece later.
5. 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 for inoculation.
6. Next, we will get our parent culture.
7. Take your parent culture, remove the cap and stopper and then flame the opening. It is essential to avoid touching the stoppers on any surfaces to keep them clean.
8. Then pour a small amount into the new flask without touching the sides.
9. Flame the openings of both flasks, replace the caps and stoppers, and return them to your culture chamber.

All set! Now we will label our new culture vessel. If transferring more than one species at a time, it is crucial 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 go a long way 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.