"LEDs and algae – "The possibilities are endless"
What wavelengths of light should I use for my algae?
Despite their difference in size and biology, cyanobacteria and algae use pretty much the same photosynthetic machinery as found in land plants. This means that the light capture at the core of the photosystems is similar. The key difference is in the cellular structures and chemistry surrounding the photosynthetic machinery.
The cellular structures attached to the photosynthetic center are called the antennae. Similar to television and radio antennae, their shape and structure dictate which signals are brought in. Different algae have adapted to different light environments through the formation, or altering, of light-capturing pigments within the antennae. One way to understand what wavelengths of light are likely to be utilized by a specific alga is to extract and analyze the pigments which are integrated into the structure of its antennae.
In addition to differences in the wavelengths captured by the antennae, the amount of biomass outside of the photosynthetic machinery can have an effect on the wavelengths utilized. In a recent lecture at the University of Arizona, I gave an example of this by showing that cyanobacteria, with very little biomass, absorbed only the basic pigment-related wavelengths. A strain of green algae, with more surrounding biomass, absorbed a wider range of wavelengths than the cyanobacteria. And finally, a plant canopy absorbed the broadest wavelength spectrum due to the additional cells and leaf tissue.
Why use LEDs with algae?
There are many reasons LEDs are ideal for lighting algae cultures. Just like in greenhouses, outdoor systems are at the mercy of available sunlight – which can change depending on the weather or time of year. In order to maintain optimal productivity, growers must install lighting systems. Legacy lighting such as high pressure sodium, metal halide, or fluorescent light, have harmful chemicals that could contaminate the ponds if they were to break. Also, these lights have wavelengths that are not ideal for photosynthesis and they are energetically inefficient. Low profile LED systems with the appropriate wavelengths are safer, increase growth rates, and are significantly cheaper to operate than legacy lighting.
Read more at the Illumitex blog.