Microalgae Growth : Key Parameters

Growing microalgae can seem complicated because there are so many factors that need to be just right for a successful algae culture.  In this article we are going to briefly explain some of these factors and why they are important.

Microalgae are an evolutionarily diverse group of organisms that come in many colours and shapes. They are united by their small size (1 – 100 µm for single cells, larger for colonies) and their ability to photosynthesize.  Despite their diversity, they share eight standard requirements for growth that must be just right for a successful algae culture, which include:

• Light
• CO2
• Nutrients
• pH
• Temperature
• Salinity
• Biosecurity 
• Harvest rate

How vital are Light and CO2 in Algae Growth?

Algae might not be considered plants by most people, yet they use Photosynthesis, the process by which microalgae use energy from light to fix CO2 and produce sugars and oxygen. To ensure good photosynthetic growth, you need to ensure you have plenty of light and carbon (usually CO2) available.

So, if you want to grow algae photosynthetically, you need to make sure you have plenty of light and carbon (usually CO2) available.

How Nutrients Support Algae Growth?

To support growth, microalgae require additional nutrients to build their cells. Among these, you can see that Nitrogen and phosphorus are in the highest demand, and many other nutrients are needed in much smaller amounts, such as metals and vitamins. Whether you are growing diatoms, you will require access to silicon in addition to the other nutrients. 

How pH, Temperature and Salinity Support Algae Growth?

For cell growth, it is also essential to provide favourable abiotic conditions. The main factors to consider here are the pH, temperature and salinity of the culture media. A good starting point for these parameters is to match the environment where your species would occur naturally. E.g. does it grow in the tropics or in the Arctic?  Freshwater or marine?. Depending on where your species’ natural environment is, so should be your parameters for pH, temperature and salinity.

How Important is Biosecurity?

Algae is a very fragile organism that can be affected terribly by drastic changes in its environment or by other organisms. This is why biosecurity is an essential consideration for culturing algae.  In this context, biosecurity refers to measures taken to prevent organisms other than the cultured species from entering your algae culture. 

For most applications, algae is cultured as a single species, and it takes a lot of work to keep it that way. So, following all biosecure procedures is a fundamental way to ensure a thriving culture.

How does Harvest Rate Play a Role as a Key Parameter for Algae Growth?

Lastly, it is important to consider harvest, because it influences the rate and quality of the growth. By harvesting, you will prevent a culture’s growth from declining by refreshing the conditions.  How often and how much should you harvest? This depends on several factors, such as your species’ growth rate and the system you use to grow it. There are many approaches, each with its own benefits and drawbacks.

Industrial Plankton manufacturers and supplies various size PBRs, including the PBR 1250L, where you can adjust conditions and watch growth parameters change in real time to ensure optimal conditions. Explore more algae production equipment here.

In future blog posts we will be discussing these microalgae growth parameters in more detail, and how Industrial Plankton PBRs can keep them optimal for algae growth. So stay tuned!