Ulvan is a sulfated heteropolysaccharide present in the cell wall of Ulva species with unique structural properties and technological potential. Here we characterized by FTIR and NMR analysis the structure of ulvan from Ulva fasciata collected in natural environment (SEA) and after in vitro biomass cultivation in nutrient enriched water (CULT). FTIR spectrum of CULT ulvan presented stronger signals of sulfate groups than SEA. 1 H and 13 C NMR showed that both ulvan are composed mainly of ulvanobiuronic acid 3-sulfate type A and type B. SEA ulvan presented signals characteristics of xylose, suggesting the presence of ulvanobiose in its structure, while CULT presented most signals of type A disaccharide. The cultivation of Ulva could be an alternative to suffice the emerging demand for ulvan meeting requirements of quality and quantity.

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This study evaluates the influence of depth and environmental parameters on the development of Gracilaria birdiae Plastino & Oliveira (Gracilariaceae) in an organic shrimp pond. The macroalgae was cultivated on modules placed at three depths (surface, 10 and 20 cm depth). Growth rates were measured weekly based on variation in fresh weight during 35 days. G. birdie showed the greatest productivity (35.7%) at 10 cm, followed by 20 cm (33.4%) and surface (25.3%). Average SGR values were 0.36±0.57% d-1(surface) 0.38±0.96% d-1 (10 cm) and 0.38 ±0.54% d-1(20 cm), over the study period. The biomass variation of G. birdiae showed significant difference among the three depths. The correlations generated by multiple regressions demonstrated that analyzed environmental parameters explain from 62 to 67 % of G. birdiae growth.

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