Cultivation of microalgae in closed systems under artificial lighting
Potential applications of microalgae include the production of food supplements, animal feed and fertilizer, waste-water treatment and as a renewable resource for biodiesel. Currently the commercial use is limiting the biotechnological potential of algae because of the low efficiency of the yields and extraction of sensitive products and high processing costs. Microalgae can be produced in open and closed systems. Light, provided by sunlight or artificial light sources, is a key parameter for microalgae growth and the biosynthesis of several high value compounds. Artificial lighting offers the option of defined conditions regarding the target of microalgal biomass as well as special metabolites. However, artificial light is the main cost factor (energy intensive) during processing. Sunlight can be used as a cheap light source but it has low photosynthetic efficiency and shows fluctuating, unstable conditions. Compared to other light sources, light emitting diodes (LED) provides advantages of small size, long life-expectancy and minimized heat generation by electrical efficiency and emitting monochromatic light. The microalgae species, C. vulgaris was cultivated photoautotrophly with exposure to LED lights (combination of 49:26:25 red:blue:green LED) as well as with fluorescent lights (FL) in a 20:4-h light:dark regime for about 240 h. Measurements of growth patterns and biochemical profiles showed a higher biomass yield (+20%) according to a higher cell concentration (+12%). Although chlorophyll and protein contents were much less compared to FL exposed cultures, the higher biomass yield means more of these compounds can be produced.
Scharff, C., Domurath, N., Wensch-Dorendorf, M. and Schröder, F.-G. 2017. Cultivation of microalgae in closed systems under artificial lighting. Acta Hort. (ISHS) 1170:1157-1164
green algae, light, LED, wavelength, growth