Characterization of agar from Gracilaria tikvahiae cultivated for nutrient bioextraction in open water farms

Rocha, Cristina M. R.; Sousa, Ana; Kim, Jang K.; Magalhães, Júlia M.C.S.; Yarish, Charles; Gonçalves, M. P.

doi:10.1016/j.foodhyd.2018.10.048

Cited by 40 publications

(24 citation statements)

References 70 publications

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“…Peaks from the spectra of the extracted gel were compared with those of an agarose Type I standard, and are shown in Table 4 with peak assignments determined from agreement with a previous study on extracted agar characterization by Rocha et al (2019). A comparison of the two spectra, stacked together are shown in Figure 4.…”

Section: Resultsmentioning

confidence: 74%

An Investigation on Zinc Biosorption with Agar Extraction Waste from Gracilaria tenuistipitata

Carisma¹,

Gonzales²,

Lazaro-Llanos³

2020

KIMIKA

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This study determined the biosorption capacity of algal waste, obtained through agar extraction from Gracilaria tenuistipitata, a common red seaweed in the Philippines and potential biosorbent, on Zn2+ ions. Agar was extracted from the seaweed and characterized through Fourier-transform infrared spectroscopy (FT-IR). The algal waste was then subjected to a biosorption study involving various Zn2+ standards. Atomic absorption spectroscopy (AAS) and FT-IR were employed to evaluate sorption processes. Biosorption data was analyzed using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms which yielded values of 0.9680, 0.8103, and 0.5254, respectively. The Langmuir ( ), Freundlich ( ), and D-R ( ) constants garnered were 0.0231 L/mg, 0.9829 mg/g, and 2.159 10-6 mol2 J-2 respectively, qualifying the adsorption of Zn2+ ions onto the algal waste as a favorable and physical process. FT-IR spectra analysis suggests that carboxylic acid and amide groups are involved in biosorption, possibly an ion-exchange process taking place for the uptake of Zn2+ ions. It was concluded that G. tenuistipitata waste is a promising biosorbent for Zn2+ ions. Performing the biosorption procedure in triplicates and the inclusion of kinetic studies are recommended to improve and ensure the accuracy in determining biosorption capacity and optimization in future studies.

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Section: Resultsmentioning

confidence: 74%

An Investigation on Zinc Biosorption with Agar Extraction Waste from Gracilaria tenuistipitata

Carisma¹,

Gonzales²,

Lazaro-Llanos³

2020

KIMIKA

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“…The best agar production of Gracilaria tenuistipitata (24.8 + 3.0 %DW) in laboratory was found at 25 psu (Bunsom and Prathep., 2012). Rocha et al (2018) stated that, often, yield of agar of G. tikvahiae has been clearly connected with salinity and adversely with nitrogen content, similarly reported to G. gracil species (Martin et al, 2013). Nitrogen concentration in LS, in fact, is lower than HS (Table 1).…”

Section: Agar Percentage and Characterizationmentioning

confidence: 82%

The Agar Production, Pigment and Nutrient Content in Gracilaria sp. Grown in Two Habitats with Varying Salinity and Nutrient Levels

2021

JJBS

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Gracilaria sp. is rich in agar, pigment, carbohydrate and mineral contents. This study aims to determine the content of agar, chlorophyll a, carotenoids and nutrient content (protein, carbohydrate, total lipid, ash, water) in Gracilaria sp. grow in different habitats with high and low salinity. Samples were brought from high salinity (44+0.33) ppt from the reservoir habitat and low salinity (26.98+0.15 ppt) from biofilter's shrimp waste pond habitat. Salinity and water quality parameteres were observed in three different subsites. Agar was extracted by alkali methods. Agar spectra were compared to standard agarose and characterized by FT-IR analysis. Results showed that agar content (25.79 ± 0.28%), chlorophyll a (25.79 ± 0.28 mg/g), carotenoid (5.90 ± 0.07 µmol/g) on low salinity was significantly higher (P<0.05) than high salinity. In high salinity, the agar (6.6+0.34%), chlorophyl a (3.62+0.15, carotenoids (0.71+0.1 µmol/g) contents was lower. The protein level of low salinity (14.4 ± 0.70%) was also significantly higher compared to high salinity (8.15+0.25%), respectively. The total lipid, carbohydrate, water, and ash content were similar. FT-IR analysis spectra show the presence of 3,6-anhydro-L-galactose. These can be useful data concerning optimum salinity in Gracilaria sp. culture.

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“…The band at 1607 cm −1 , assigned to amide I vibrations, indicates that proteins are present (Figure 6B) [33]. The presence of proteins in agar indicates that the pigment is not completely removed [1]. The bands at 1380 and 1250 cm −1 are related to the total sulfate content and indicate agar quality because the presence of α-L-galactose 6-sulfate units decreases the gel strength.…”

Section: Ft-ir Analysis Of Agar Extracted From Each Proceduresmentioning

confidence: 99%

“…Agar is one polysaccharide obtained from the cell wall of red seaweeds. It is commercially used as a thickening, gelling, stabilizing, and restructuring agents in various food formulations [1], as culture media in biological research [2], as a biodegradable carrier for drug delivery systems in the pharmaceutical industry [3], as well as agar-based nanoparticles in nano-bioengineering fields for wastewater treatment [4], as hydrogel films in functional food packaging, and wound dressing [5]. Agar is composed of two major components, agarose and agaropectin, respectively.…”

Section: Introductionmentioning

confidence: 99%

Pretreatment Techniques and Green Extraction Technologies for Agar from Gracilaria lemaneiformis

et al. 2021

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Optimizing the alkali treatment process alone without tracking the changes of algae and agar quality with each pretreatment process will not achieve the optimal agar yield and final quality. In this study, we monitored the changes of the morphology and weight of algae with each treatment process, and comprehensively analyzed the effects of each pretreatment process on the quality of agar by combining the changes of the physicochemical properties of agar. In conventional alkali-extraction technology, alkali treatment (7%, w/v) alone significantly reduced the weight of algae (52%), but hindered the dissolution of algae, resulting in a lower yield (4%). Acidification could solve the problem of algal hardening after alkali treatment to improve the yield (12%). In enzymatic extraction technology, agar with high purity cannot be obtained by enzyme treatment alone, but low gel strength (405 g/cm2) and high sulfate content (3.4%) can be obtained by subsequent acidification and bleaching. In enzyme-assisted extraction technology, enzyme damage to the surface fiber of algae promoted the penetration of low-concentration alkali (3%, w/v), which ensured a high desulfurization efficiency and a low gel degradation rate, thus improving yield (24.7%) and gel strength (706 g/cm2), which has the potential to replace the traditional alkali-extraction technology.

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Characterization of agar from Gracilaria tikvahiae cultivated for nutrient bioextraction in open water farms

Cited by 40 publications

References 70 publications

An Investigation on Zinc Biosorption with Agar Extraction Waste from Gracilaria tenuistipitata

An Investigation on Zinc Biosorption with Agar Extraction Waste from Gracilaria tenuistipitata

The Agar Production, Pigment and Nutrient Content in Gracilaria sp. Grown in Two Habitats with Varying Salinity and Nutrient Levels

Pretreatment Techniques and Green Extraction Technologies for Agar from Gracilaria lemaneiformis

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