Aline P. Martins1, Nair Sumie Yokoya2 and Pio Colepicolo1
1 Institute of Chemistry, University of Sao Paulo, Sao Paulo, SP, Brazil
2 Biodiversity Conservation Center, Environmental Research Institute, São Paulo, SP, Brazil
Seaweeds are important autotrophic organisms that produce numerous metabolites with potential for biotechnological application, such as carbohydrates, which can be used to generate bioethanol. Thus, with the aim of maximize the production of fermentable monosaccharides from Ulva biomass, this study evaluated the combined influence of light, temperature and availability of nitrate and phosphate, using the factorial design technique, on the growth, photosynthesis, and monosaccharides content of Ulva lactuca from Ubatuba, SP, Brazil. The content of total lipids and fatty acids was also accessed since they can be used as nutraceuticals and aggregate value to the use of the biomass of macroalgae. The seaweeds were cultivated by ten days, with the abiotic factors varying as following: irradiance – 50 to 150 mmol photons m2 s-1; temperature – 15 to 30 °C; nitrate concentration – 20 to 250 mmol L-1; and phosphate concentration: 2 to 18 mmol L-1. The highest growth rate and photosynthesis, obtained at high irradiance and high nutrients availability, were 17% d-1 and 70.1 mmol electrons m2 s-1, respectively. The omega-3 concentration was also higher under these conditions, reaching 50% of the total fatty acid content. The highest concentration of total monosaccharides and glucose were 128 and 73 mg/g dry mass, respectively, and occurred in the treatment with the lowest concentration of nitrate. The results show the importance of cultivation conditions for maximizing the production of the compound of interest as well as the potential of Ulva lactuca to produce bioethanol and other compounds.