What Is a Photobioreactor?
A photobioreactor is a sealed cultivation system designed for growing photosynthetic organisms, including microalgae. It typically consists of transparent tubes or flat panels through which the algae culture circulates, receiving light through the walls while remaining physically isolated from the external environment.
If you see "grown in a photobioreactor" on a supplement label, it means the algae were cultivated in a controlled, sealed system rather than an open outdoor pond. If you do not see any cultivation method mentioned on the tub or capsule packaging, that is worth questioning. The growing system directly affects the purity and consistency of the product you are taking.
The distinction between sealed and open cultivation is not academic. Open ponds expose the culture to airborne bacteria, insect contamination, heavy-metal-carrying dust, and competing algal species. You cannot control what lands in an open pond. A photobioreactor removes that variable entirely, which is why the method matters when you are choosing a supplement that goes into your body every day.
Why Photobioreactor Cultivation Matters on Your Supplement Label
We grow our marine phytoplankton in closed photobioreactors. We chose this method because it eliminates the environmental contamination pathways that open-pond cultivation introduces: airborne pollutants, competing organisms, and variable water quality that can concentrate heavy metals in the final product.
The trade-off is cost. Photobioreactor systems require more infrastructure and energy than open ponds, which is reflected in the retail price of supplements produced this way. When you compare two algae products and one costs noticeably more, the cultivation method is often the reason. We covered the full comparison in our photobioreactor vs open pond article and the contamination implications in our heavy metals guide.
Photobioreactors at a Glance
- What it is: A sealed, controlled system for cultivating photosynthetic microalgae
- Structure: Transparent tubes or panels, controlled water, nutrients, CO2, temperature
- Purity advantage: No airborne contaminants, no competing organisms, no environmental pollutants
- Consistency advantage: Controlled light, temperature, and nutrients produce stable batch-to-batch profiles
- Cost: More expensive than open-pond systems, reflected in product pricing
What our research found
The energy cost is the real price driver. Published data puts photobioreactor energy consumption at 4.5 to 8.2 kWh per kilogram of dry biomass. Open raceway ponds use 0.1 to 0.7 kWh per kilogram. That is a ten- to forty-fold difference in electricity alone, before you account for the sealed infrastructure.
Open-pond cultures can collapse within two days. When grazers like rotifers or competing algal species enter an open pond, they can consume or outcompete the target culture fast enough to crash the entire batch. PBR systems physically exclude these organisms, which is why batch-to-batch consistency is higher and contamination testing results are cleaner.
Sources
- Wang B et al. Photobioreactors for cultivation and synthesis: Specifications, challenges, and perspectives. Biotechnology Advances. 2022;36(4):107823. PubMed
- Singh RN, Sharma S. Development of suitable photobioreactor for algae production — a review. Renewable and Sustainable Energy Reviews. 2012;16(4):2347–2353. PubMed
Cara Hayes, MSc Nutrition and Dietetics (University of Sydney), writes all content in the Phytality Knowledge Centre. Read our editorial policy.
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Consult your healthcare provider before starting any supplement.
Methodology and Disclosure
Phytality uses closed photobioreactors for its marine phytoplankton cultivation. We have a commercial interest in this method being valued. Descriptions reflect established aquaculture engineering. No EFSA-authorised health claims are cited.
Last reviewed: March 2026
