Light regulating metabolic responses of cyanobium sp. (cyanobacteria)

Abstract

Cyanobacteria are an important group of microorganisms of significant economic interest due to, for ex-ample, the antioxidant capacity of their metabolites. Cyanobium sp. LEGE 06113 is a marine cyanobacterium poorly studied, but with promising future applications. The aim of this study was to optimize the light conditions (both source and irradiance) and nutrient (N and P) concentration for Cyanobium sp. production as a source of high-valued com-pounds. The optimization of the processing parameters was performed using two different light sources (fluorescent and low-pressure sodium lamp), four irradiances (50, 100, 200 and 300 µmol photons m-2s-1) and two variations of BG11 medium (BG11 and BG11+, with the second containing double amounts of phosphates and nitrates). The effects of the three factors were evaluated on the biomass production, photosynthetic activity, biochemical composi-tion and antioxidant capacity. A synergistic effect between the light source, light intensity, and medium was observed for all measured parameters, with the greatest impact of light irradiance on the metabolism of Cyanobium sp. The combination of the SOX lamp, BG11+ medium, and a light irradiance of 200 µmol photons m-2s-1 was optimal for the cultivation of Cyanobium sp. This work reports the tools for the production of Cyanobium sp. as a source of high-value products, thus increasing its biotechnological potentials.