ABSTRACT
Growth of phototrophic microorganisms (algae and cyanobacteria) depends on the quantity (duration and intensity) and quality (colour or wavelength) of light. Microorganisms only use the spectral energy corresponding to peak absorption of pigments. Monochromatic LED lamps have a narrow spectral bandwidth and therefore may be useful for controlling the growth of phototrophs. To address this topic, we characterized the spectra of green, blue and red LED lamps. We also extracted the pigments from five cultures derived from biofilms developed on granite buildings and measured their specific UV-Vis absorption spectra. Conclusions drawn from the findings were checked, exposing one culture under study to light from the three LED lamps: the biofilm thrived well under blue LEDs, whereas red and especially green LEDs had a weak biostatic effect. These results were consistent with the previous hypotheses from the superimposition of spectra. Exposition of other phototrophic cultures to monochromatic LED lamps will be performed in future research.
