Photon up-conversion increases biomass yield in Chlorella vulgaris

Area of Science:

• Photochemistry and Photobiology
• Algal Biotechnology
• Renewable Energy

Background:

• Photosynthetically active radiation (PAR) is limited, wasting solar spectrum regions.
• Some solar wavelengths can be damaging to microalgae.
• Photon up-conversion offers a method to utilize broader solar spectrum regions.

Purpose of the Study:

• To investigate photon up-conversion as a strategy for enhancing microalgal growth and lipid productivity.
• To evaluate the effects of up-converted red light on Chlorella vulgaris.
• To assess the impact of up-conversion on biomass concentration, growth rate, and lipid content.

Main Methods:

• Utilized photon up-conversion with two distinct sets of up-conversion phosphors.
• Applied up-conversion of red light (654 nm) to cultures of Chlorella vulgaris.
• Measured biomass concentration, specific growth rate, intracellular neutral lipid content, and reactive oxygen species levels.

Main Results:

• Set 1 phosphors increased biomass concentration by 2.85-fold and specific growth rate by 3.2-fold.
• Set 2 phosphors increased biomass by 30% and specific intracellular neutral lipid by 12%.
• Up-conversion led to higher intracellular reactive oxygen species levels and improved biomass yields.

Conclusions:

• Photon up-conversion is a viable strategy to improve microalgal biomass and lipid productivity.
• This technology broadens the usable solar spectrum for photosynthetic organisms.
• Up-conversion holds potential for enhancing the cultivation of algae, plants, and other photosynthetic systems.