Wild Undaria pinnatifida from Golfo Nuevo (Patagonia, Argentina) as biomass feedstock for wakame, fucoidan and phenolic extract production.

IXTAINA, V.; PONCE, NORA M.A; SERRA, M. ; SOLANA, VALERIA; VALLEJO, M.; LATOUR, EZEQUIEL A.; DELLATORRE FERNANDO G.; MARGUET, E. R.; ARIJON, MARIANELA; STORTZ CARLOS A.

Chiba

Conferencia; 7th Conference of the International Society For Applied Phycology; 2021

International Society for Applied Phycology

Undaria pinnatifida (Harvey) Suringar (Phaeophyta, Laminariales) was detected in Argentina in 1992. After ~ 30 years of spreading along Argentine coasts, it currently develops dense seasonal kelp forests along ~10 degrees of latitude. To have information about seasonal evolution of biomass availability, quality and yield for potential productive uses, we conducted a year-round monthly sampling program in the south-west coast of Golfo Nuevo (Patagonia, Argentina). Each sampling date, five 1 m2 quadrats were randomly deployed, over a region of ~1 ha with homogeneous hard bottom and 4 m depth. U. pinnatifida thalli (attached or unattached) were collected by SCUBA diving. In the laboratory, there were classified all specimens according to their morphological development [1]. Morphological traits were measured according to Choi, et al. [2] including blade thickness. Blade, midrib and sporophyll of each specimen were dissected and weighed. Subsamples of different tissues were dried accordingly to measure 1) sporophyll fucoidan yield, monosaccharide composition and sulphate content, 2) arsenic and cadmium content, and 3) antioxidant activity and total phenolic content. Average wet biomass density increased from 0 (April/June) to ~4200 g m-2 (November). Thin blades (160-200 µm) dominated thalli biomass. Between November-March blades get thickened (300 µm) and eroded to virtually disappear. Instead, sporophyll proportion increased and its wet biomass density ranged between 440-650 g m-2. High biomass proportion (24-45 %) of drifting sporophytes was detected between November and February. Average sporophyll fucoidan content increased from ~15% (dry weight basis) in November/December, to ~20% in January/February. Arsenic and cadmium content were higher in blade (As 39.6 ±4.6 ppm; Cd 4.2 ±0.5 ppm) and sporophyll (As 44.6 ±5.0 ppm; Cd 4.5 ±0.5 ppm) than in midrib (As 25.7 ±1.7; Cd 2.3 ±0.4), and seasonally stable. Antioxidant capacity (AC, mg ascorbic acid eq/100 g dry weight) and total phenolic content (PC, mg gallic acid eq/100 g dry weight) were higher in sporophyll (AC 737 ±158, PC 867 ±321) than in blade (AC 396 ±192, PC 484 ±288) and in midrib (AC 311 ±138, PC 189 ±108). Slight seasonal increments were not statistically significant. From August to November biomass could be suitable for wakame production although it should be necessary to consider other quality factors like color [3], hairs (cryptostomata), wrinkles (Y. Sato pers. comm.), erosion and epiphytes. From October to March, high sporophyll density could be suitable as biomass feedstock for production of valuable fucoidan or phenolic extracts, potentially through a biorefinery approach.