Microalgal biotechnology offers a promising platform for the sustainable production of diverse renewable bioactive compounds. The main difference from other microbial bioprocesses is the crucial role that light plays for cultures since it can be used as a source of environmental information to control metabolic processes. Therefore, we can use these criteria to design a bioprocess that aims to stimulate the accumulation of target molecules by controlling light exposure. We study the effect on biochemical and photobiological responses of Golenkinia brevispicula FAUBA-3 to the exposition of different spectral irradiances (high-fluence PAR of narrow yellow spectrum complemented with low intensity of monochromatic radiations of red, blue, and UV-A) under pre-stress and salinity stress conditions. High light coupled to salinity stress affected the photosynthetic activity and photoprotection mechanisms as shown by maximal quantum yield ( Fv/Fm) and non-photochemical quenching (NPQ max) reduction, respectively. High light treatments combined with the proper dose of UV-A radiation under salinity stress induced the highest carotenoid content (2.75 mg g DW -1) composed mainly of lutein and β-carotene, and the highest lipid accumulation (35.3 % DW) with the highest PUFA content (ALA (C18:3) and LA (C18:2)). Our study can guide the strategies for commercial indoor production of G. brevispicula for high-value metabolites.

Biofouling represents an important limitation in photobioreactor cultures. The biofouling propensity of different materials (polystyrene, borosilicate glass, polymethyl methacrylate and polyethylene terephthalate glycol-modified) and coatings (two spray-applied and nanoparticle-based superhydrophobic coatings and a hydrogel-based fouling release coating) was evaluated by means of a short-term protein test, using bovine serum albumin (BSA) as a model protein, and by the long-term culture of the marine microalga Nannochloropsis gaditana under practical conditions. The results from both methods were similar, confirming that the BSA test predicts microalgal biofouling on surfaces exposed to microalgae cultures; these secrete macromolecules, such as proteins, that have a high capacity for forming a conditioning film prior to cell adhesion. The hydrogel-based coating showed significantly reduced BSA and N. gaditana adhesion, whereas the other surfaces failed to control biofouling. Microalgal biofouling was associated with an increased concentration of sticky extracellular proteins at low N/P ratios (below 15).