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To grow algae in a laboratory, match the culture’s source conditions, give it a suitable liquid or agar medium, transfer it with aseptic technique, and keep it on a controlled light and temperature schedule. This guide covers laboratory culture of microalgae obtained from a culture collection, using the published practice of two collections: the UTEX Culture Collection of Algae at the University of Texas at Austin and CCAP, the Culture Collection of Algae and Protozoa in the UK. It is not about ponds, aquariums or fuel production.
The parameters below, including temperature, photoperiod and the light ceiling, come from the published practice of those collections and are attributed to them in the Sources section.
What you need
- A starter culture from a collection. Collections such as UTEX and CCAP supply defined strains. Their instructions for your strain take priority over anything general on this page.
- A culture medium suited to the strain. UTEX sorts its media recipes into two broad water types, freshwater and marine. Its freshwater list includes Bold Basal Medium, BG-11 Medium, Proteose Medium and Modified Bold 3N Medium. CCAP lists media by acronym, including BG11 (Blue-Green Medium), ASW (Artificial Seawater), NSW (Natural Seawater) and soil-extract media such as SE1 and SE2.
- A temperature-controlled incubator or culture room. UTEX holds its collection at 20 °C, in incubators set to 20 ± 1 °C, with one at 25 ± 1 °C for some tropical chlorophytes and the Dasycladales.
- Lighting you can time and keep within a ceiling. UTEX uses a mix of cool-white and warm-white fluorescent lamps at no more than 3200 lux on a 12 h light, 12 h dark cycle.
- Aseptic transfer equipment. UTEX transfers agar cultures in a laminar flow hood with metal loops flamed over a Bunsen burner, or with autoclavable wooden sticks. Axenic liquid cultures are transferred in a laminar hood with a Pasteur pipet fitted with a 1 mL bulb. For background, see the guides on laminar flow hoods, autoclaves and aseptic technique.
Steps
- Read the supplier’s instructions for the strain. Note its recommended medium and conditions.
- Start by copying the collection’s conditions. UTEX advises duplicating the Collection’s conditions “within reason” when a culture arrives, to reduce the chance of losing it. Once stock is established, subcultures can be used to test other conditions.
- Prepare the medium. Use the recipe the collection names for the strain. Take the components, concentrations and sterilization from the collection’s own preparation page for that medium. CCAP notes that its ASW:BG medium is made up in two parts that are autoclaved separately and mixed aseptically when cool.
- Transfer the culture aseptically. Use the method that fits the culture type: flamed loop or sterile stick for agar cultures, in a laminar flow hood, and flame the tube before and after it is entered. For axenic liquid cultures use a Pasteur pipet in the hood; UTEX notes flaming is not necessary for these. UTEX transfers xenic cultures in the open work areas of its culture rooms.
- Put the new culture on a lighted shelf to grow. At UTEX this is usually one to two weeks, on the 12/12 h cycle at no more than 3200 lux.
- Move it off the lights for storage. After growth, UTEX moves cultures to a shelf away from the lights until needed.
- Transfer again on a schedule. The interval depends on the strain. UTEX transfers cultures at intervals from two weeks to nine months.
What can go wrong
Light stress
Some groups are light-sensitive. UTEX names colorless euglenoids, Polytoma, Polytomella, Prototheca and heterotrophs such as Ochromonas and Poterioochromonas, and advises keeping them away from bright light. Blue-green algae often do well on a lighted shelf when the light is reduced with a neutral density filter, for example a sheet of white bond paper between the culture and the lights.
Contamination
UTEX transfers agar cultures in a laminar flow hood, flaming loops and flaming each tube before and after it is entered, and transfers axenic liquid cultures with a Pasteur pipet in the hood. Follow the same kind of aseptic handling for your own cultures. For the equivalent problem in animal cell work, see cell culture contamination.
Wrong medium or water type
Freshwater and marine strains use different media families. If a strain does not grow, check first that you are using the medium the collection lists for it. CCAP checks only its recipes marked “QA” annually under its ISO 9001:2015 accreditation, and states that it cannot guarantee the accuracy of the others, so prefer the collection’s QA recipe where one is given.
Changing too much at once
Because UTEX advises matching its conditions at first, change one variable at a time on a subculture and keep the original stock running.
When to get professional help
Contact the collection that supplied the strain if a culture will not establish, if you need a medium recipe not described on its public pages, or if you want to know how a strain is preserved. UTEX states that most soil and many freshwater algae in its collection are permanently cryopreserved. Questions about containment or approval to hold a particular organism go to your institution’s biosafety office; see biosafety levels BSL-1 to BSL-4.
FAQ
How long does algae take to grow in the lab?
For UTEX stock cultures, a newly transferred culture goes on a lighted shelf for usually one to two weeks. Other strains and conditions will differ, so follow the supplier’s guidance for yours.
Do algal cultures need aeration?
Not in a collection setting. UTEX states that during the life of its cultures, none are aerated or agitated.
Which medium should I use?
The one the collection lists for your strain. Media are grouped as freshwater or marine, and common freshwater examples include BG-11 and Bold Basal Medium. For general cell culture media, which is a separate topic, see types of cell culture media.
What temperature and light do algae cultures need?
UTEX holds its collection at 20 ± 1 °C, with a 25 ± 1 °C incubator for a few tropical strains, under no more than 3200 lux on a 12/12 h light/dark cycle.
Sources
- UTEX Culture Collection of Algae, Culture Maintenance, checked 2026-10-29.
- UTEX Culture Collection of Algae, Algal Culture Media, checked 2026-10-29.
- CCAP, Culture Collection of Algae and Protozoa, Media Recipes, checked 2026-10-29.
