Effect of dark and salinity treatment in the yield and quality of agar from Gracilaria cornea (Rhodophyceae)

Abstract

289Efecto del tratamiento de oscuridad y salinidad en el rendimiento y calidad del agar de Gracilaria cornea (Rhodophyceae)Effect of dark and salinity treatment in the yield and quality of agar from Gracilaria cornea (Rhodophyceae) Yolanda ResumenEl tratamiento alcalino previo a la extracción del agar del género Gracilaria reduce, entre otras reacciones, el contenido de sulfatos y aumenta la fuerza de gel; sin embargo, a nivel industrial, requiere de costosos procesos de purificación de los efluentes para reducir los niveles de contaminación. El alga roja Gracilaria cornea fue cultivada bajo diferentes tratamientos de oscuridad y salinidad antes de su cosecha con el propósito de remplazar dicho tratamiento alcalino. Los diferentes tratamientos realizados fueron: (a) oscuridad y 33‰ de salinidad durante 8 días, Todos los tratamientos redujeron el contenido de sulfatos en el agar en aproximadamente un 24% cuando se les compara con el agar obtenido sin ningún tratamiento. Para G. cornea el tratamiento [4+4] puede en el futuro llegar a ser un método adicional a un tratamiento alcalino ligero en el que se utilice una menor concentración de álcali durante la extracción de agar.Palabras clave: Agar, Gracilaria cornea, salinidad, tratamiento de oscuridad. AbstractThe alkali treatment used previous to agar extractions from the Gracilaria genus reduces, among other reactions, the sulphate content and improves the gel strength; however, at an industrial level it requires expensive effluent processing to reduce its polluting charge. The red alga Gracilaria cornea was cultivated under dark and salinity treatments to replace this alkali treatment. The different treatments tested were: (a) darkness and 33‰ salinity for 8 days, [dark treatment]; (b) darkness and 50‰ salinity for 4 days, followed by darkness and 25‰ salinity for 4 days, [4+4]; and (c) darkness and 50‰ salinity for 8 days, followed by darkness and 25‰ salinity for 4 days, [8+4]. The treatment [4+4] increased the agar yield in 26% (from 36.6 to 46.1%). All treatments reduced the sulphate content of the agar in approximately 24% when compared with agar obtained without any treatment. For G. cornea the [4+4] treatment might become in the future an additional treatment to a mild alkali treatment using less alkaline reagents for agar extraction.

Does salinity affect growth and carrageenan yield of Kappaphycus alvarezii (Gigartinales/Rhodophyta)?

“…and carragenophytes like Chondrus sp. and Solieria sp., to increase the cell‐wall contents of such components in order to rapidly mitigate any harmful consequences caused by either salinity, light or water motion (Goulard, Diouris, Quere, Deslandes & Flocapos 2001; Freile‐pelegrín, Robledo, Pedersén, Bruno & Rönnqvist 2002; Villanueva, Hilliou & Sousa‐pinto 2009). They directly contribute to the osmotic equilibrium of the cell (Percival 1979) and it is important to the survival of the algae in sites with fluctuating salinity conditions (Percival & McDowell 1967).…”

Integral Utilization of Red Seaweed for Bioactive Production

“…An alternative pretreatment was proposed by Roleda [58], which consisted of soaking the Gelidiella acerosa air dried sample in 0.5% acetic acid for 1 h at 16–20 °C, then 1 h steam pressure at 15–20 psi and boiling at 100 °C. Freile-Pelegrín [59] proposed the cultivation of Gracilaria cornes under dark and salinity treatments (50 and 25% salinity) to replace the alkali treatment. Pigments, such as chlorophyll, carotenoids and phycoerythrobilin, can be leached out during the alkaline pretreatment and an alternative environmentally friendly scalable photobleaching process for Gracilaria asiatica and Gracilaria lemaneiformis with 3–5% NaOH and photobleaching for 5 h was proposed [60].…”

Physicochemical properties of wild and cultivated Saccharina latissima macroalgae harvested in the Canadian boreal-subarctic transition zone

“…Indeed, the production of several secondary metabolites is often related to seaweed's capacity of resisting and developing in harsh environments [ 10 , 29 ]. The chemical composition of macroalgae varies with species [ 7 , 30 ], habitats [ 31 , 32 ], age [ 33 , 34 ] and environmental conditions [ 35 ], such as light [ 36 ], temperature [ 37 ], and nutrients [ [38] , [39] , [40] , [41] ], and salinity [ 4 , [42] , [43] , [44] , [45] ]. The development of structural color in algae is believed to be linked to intrinsic adaptation mechanisms and is influenced by the environmental conditions, especially radiation intensity, influenced by the water turbidity [ 46 ].…”