Título: A way to produce macroalgae in terrestrial areas and the use as biostimulants
Resumen: Macroalgae have become increasingly popular over the years due to their ability to produce valuable compounds, their protein-rich composition, and their use as biofilters. The utilisation of land-based systems for algae production has been employed for decades for microalgae production due to the fact that it enables the control of multiple cultivation parameters that facilitate the attainment of a higher quality and more stable biomass throughout the year, thus meeting the standards demanded by the market.
The utilisation of biostimulants in the food industry has been a practice for many decades, exhibiting a consistent and gradual increase in adoption. This can be attributed to the economic, social and environmental viability of biostimulants. The utilization of macroalgae as growth stimulants in coastal zone culture can be observed throughout history, with diverse cultural groups employing this method. However, this practice was substituted for that of microalgae due to the enhanced ease of production in terrestrial environments and their rapid growth characteristics.
The present study focuses on the optimization of various critical parameters for the outdoor cultivation of the cosmopolitan green macroalga Ulva compressa, with the objective of attaining yields comparable to those of microalgae in raceway cultures (30 g DW m2 day-1) without water exchange. Furthermore, the study explores the potential of this biomass as a biostimulant, investigating its application through freeze-drying and heat treatment at three temperatures (45, 70 and 100°C).
The data obtained shows that using the optimal parameters of: Harvesting rate, Paddle wheel speed and Culture water height, an increase of 81.1% in Ulva productivity can be achieved when optimal parameters are applied, obtaining a productivity of 29.76 gr DW m2 day-1.
The biomass obtained from the reactors was then subjected to a freeze-drying and milling process, resulting in the production of a fine powder. This powder was utilized for the different treatments, with concentrations of 0.1, 0.5 and 2 g/L, in conjunction with an ultrasound breaking process. Additionally, 100 g/L of powder was subjected to heating for a duration of 1.5 hours at three distinct temperatures: 45, 70 and 100°C to break and dissolve the inner compounds. These extracts, designated as UL45, UL70 and UL100, were diluted to five concentrations (0.1, 0.5, 1, 2, 5%) for the biostimulant tests. It is evident from the results of these bioassays that there is variability in the effects of the different heat treatments, as well as in the dilutions that were tested.
Congreso: 1st INTERNATIONAL CONGRESS ON ALGAE BIOTECHNOLOGY
