Eucheuma Spinosum Research Articles

The Effect of Various Comparison of the Proportions of Seaweed (Eucheuma spinosum) and Gelatin on the Characteristics of Roselle Jelly Candy (Hibiscus sabdariffa L.)

Rosela flower (H. sabdariffa L.) is one of the plants that has many health benefits, which contain Vitamin C, Vitamin A, essential proteins, and 18 types of amino acids that aim to strengthen the body's immune system, treat diabetes, inhibit cancer cells and many more properties of this plant. Gelling agent commonly used to make jelly candy is gelatin, but in the application sometimes gelatin even makes the texture of jelly candy becomes very hard if the added concentration is not appropriate, besides the price of special gelatin food ( food grade) is still relatively expensive compared to other hydrocolloid materials. That's why it takes another gel shaper that can improve the quality of the texture of jelly candy and suppress the use of gelatin, one of which can be used seaweed (E. spinosum). The objective of this research was to find out the effect of various proportions of seaweed (E. spinosum) and gelatin on the characteristics of roselle jelly candy (H. sabdariffa L.). The method used is non-parametric statistical tests (Friedman test) with 10 levels of treatment and performed three times the test on each treatment. The treatment that will be done is a comparison of various proportions of seaweed: gelatin, namely PI (0: 8); P2 (0: 10); P3 (25:8); P4 (25:10); P5 (30:8); P6 (30:10); P7 (35:0); P8 (35:8); P9 (40:0) and P10 (40:8). The results showed there was a very noticeable difference in all the comparative treatment of seaweed and gelatin proportions against all test parameters. The best organoleptic test results showed color organoleptic test scores of 3.00 (neutral), organoleptic textures of 3.37 (neutral-like), organoleptic flavors of 3.40 (neutral-like) and organoleptic aromas of 3.00 (neutral).

The Effect of Seaweed (Eucheuma spinosum) Fortification on The Quality of Pekdos

This study aims to determine the effect of fortification of seaweed (Eucheuma spinosum) on the quality of pekdos and determine the amount of seaweed addition to producing the best quality of pekdos. The research method used was experimental with the processing of pekdos with the addition of seaweed porridge (E. spinosum) in different concentrations. The research design was a completely randomized design (CRD) consisting of 4 treatment levels, P0 (0%), P1 (5%), P2 (10%), and P3 (15%). Parameter analysis of organoleptic, moisture content, ash, protein, fat, and crude fiber. The results showed that seaweed fortification had a significant effect on the 95% confidence level on the quality of pekdos. The addition of 10% (P2) seaweed produced the best quality pekdos. The pekdos has a neat appearance intact, slightly hollow, attractive, and slightly yellowish-white; the aroma is not fishy, fresh, fragrant, and specific type of pekdos mackerel; tasted specific type of pekdos taste, savory, and very tasty; and a chewy soft, and easy-to-bite texture; pekdos has 37.40% moisture; 3.54% ash; 14.92% protein; 4.41% fat, and 4.39% crude fiber.

UJI MUTU REFINED KARAGINAN DARI Eucheuma spinosum BERDASARKAN PERBEDAAN KONSENTRASI KALIUM HIDROKSIDA DENGAN METODE MICROWAVE ASSITED EXTRACTION (MAE)

Carrageenan in the pharmaceutical industry can be used as a stabilizer, thickener, gelling agent, emulsifier, and binder. Alkaline solutions such as KOH have two functions, which help extract polysaccharides to be more perfect and accelerate the elimination of 6-sulfate from the monomer unit to 3,6-anhydro-D-galactose so that it can improve the quality of carrageenan. The purpose of this study is to evaluate the effect of to determine the effect KOH of differences concentration on yield carrageenan characteristics from the extraction results Microwave-assisted extraction (MAE). The carrageenan quality parameters tested water content, ash content, sulfate content and viscosity. The Eucheuma spinosum originating from the waters of Sumenep, Madura was extracted at the Phytochemical Laboratory of Pharmacy Program, Hang Tuah University, Surabaya using different concentrations of KOH 10%, 15%, and 20% with the Microwave Assisted Extraction (MAE) method which was then filtered and neutralized with filtration and neutralized with The HCl is then precipitated with ethanol 96%, drying and grinding until to obtain a fine carrageenan is powder. The carrageenan obtained was then calculated the for yield percentage and analyzed for the water content, ash content, sulfate content and viscosity. The concentration of KOH affects % yield where an average increase in yield results along with increasing the concentration of KOH, the highest yield at 20% concentration of KOH is 37.41% ± 1.186 and an analysis of the standard carrageenan quality test is carried out where those that meet the quality requirements are water content, ash content, and sulfate content. As for viscosity, there was no significant difference in the KOH concentrations of 15% and 20%.

Study of Composition and Composition of Macro Algae Habitat in the Intertidal Zone Water of Sibu Island, Nort Oba District Tidore Islands City Nort Maluku

Macro algae is a part of marine plants whose whole body is called the "thallus". Macro algae are widespread in tropical and sub-tropical waters. The purpose of this study was to determine the composition of the macro algae species, the width of the micro-habitat niches, and the overlapping of the micro-habitat niches in the intertidal zone of the waters of Sibu Island, Oba Utara District, Tidore Islands City. The data was collected using survey method using belt transects and squares measuring 1x1 m2 which are placed systematically in zigzags along the tansek belt. In this study, 20 species of macro algae were found in the waters of the island of Sibu, consisting of Halimeda macroloba, Halimeada opuntia forma chordata, Halimeda incrassata, Halimeda opuntia forma renschii, Chaetamorpha sp, Eucheuma cottonii, Sargassum duplicatum, S.polycestum, Turbina ornata, T. conoides, Padina boergesenii, Dictyota dichotoma, Amphiroa fragilissima, Acanthopora spicifera, Eucheuma denticulatum, E. spinosum, Glacilaria salicornia, Hypnea nidulans, Galaxaura apiculata. The results of the analysis of the width of the recesses showed that the macro algae species with the largest recess width were Eucheuma denticulatum with a value of 0.905, while Galaxura apiculata had the narrowest recess widths with a value of 0.200. Furthermore, based on the results of overlapping analysis of microhabitat niches, it shows that the overlap of microbaitate niches is quite large by Sargassum polycestum against Galaxaura apiculata with a value of 0.337, while the lowest was carried out by Halimeda macroloba against Galaxaura apiculata, Halimeda opuntia forma chordata against Galaxaura apiculata with a value of 0.337, while the lowest was carried out by Halimeda macroloba against Galaxaura apiculata, Halimeda opuntia forma chordata against Galaxaura apiculata, Eucheuma spinosum against Galaxaura apiculata with a value of 0.000.

Seaweed Eucheuma spinosum J. Agardh 1847, is it a bioaccumulator?

Eucheuma spinosum is a species of seaweed widely cultivated in Indonesia. This seaweed contains high carrageenan, ranging between 65-67 percent. Carrageenan plays a very important role as a stabilizer, thickener, gel maker, emulsifier and others. This property is widely used in the food industry, medicine, cosmetics, textiles, paints, toothpaste and other industries. This very important benefit requires that E. spinosum must be safe from harmful metal content. This study aims to analyze whether E. spinosum is a bioaccumulator of harmful metals. This research was conducted in three sea areas around South Sulawesi, namely the Gulf of Bone, the Flores Sea and the Makassar Strait. Seaweed samples were taken from seaweed cultivation locations in these three areas. The metal concentrations analyzed were Copper (Cu), Cadmium (Cd), and Lead (Pb). This study indicated that E. spinosum was a bioaccumulator because at each sampling location the concentrations of Cu, Cd, and Pb at E. spinosum were generally greater than those in ambient seawater. E. spinosum was non permanent or non consistent bioaccumulator because the concentrations of Cu, Cd, and Pb in E. spinosum tissue are not directly proportional to the concentrations of Cu, Cd, and Pb in seawater.

Antioxidant activity of methanolic extract of Eucheuma spinosum extracted using a microwave

Eucheuma spinosum is a widely cultivated red seaweed. The phenolic compounds contained in E. spinosum, especially flavonoids, can be used as a source of natural antioxidants. This study aimed to determine the antioxidant activity of E. spinosum extracted using a microwave with different extraction times (6, 8 and 10 minutes). The parameters measured included yield, phytochemical test, total phenolic content, total flavonoid content and antioxidant activityt, namely 2,2 diphenyl-1-picrihydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The results showed that the E. spinosum extract with an extraction time of 10 minutes had the highest yield with a total phenolic content of 59.42 ± 27.36 mg GAE/g and a total flavonoid content of 65.48 ± 25.34 mg QE/g. The results of phytochemical screening showed that the extract contain triterpenoid compounds. The antioxidant activity of the E. spinosum extract showed the highest IC50 value of 46.52 ± 5.53 ppm using the DPPH method and the FRAP method was 58.92 ± 1.76 μM/g.

Free-Radical Scavenging Activity (FRSA) of Secondary Metabolite Extracted from Indonesian Eucheuma spinosum

IIndonesia is the biggest country in the production of red seaweed of Eucheuma spinosum. The red seaweed has bioactive compounds that have a potential activity such as phenolic compounds as well as carrageenan and pigments. This paper reported phytochemical analysis of E. spinosum harvested by a local farmer in Sumenep Island, East Java and free-radical scavenging activity (FRSA) derived from 2,2’-diphenyl-1-picrylhdrazyl (DPPH) for several organic solvents. For extraction, dried powder is added with 5.0 mL of various solvents following by ultra-sonication assisted extraction for 30 minutes. The extract was separated by centrifugation for phytochemical analysis and radical scavenging evaluation. The prospecting of dichloromethane, ethyl acetate, and n-hexane extracts indicated the potency for radical scavengers. Alkaloids, terpenoids, and saponins were secondary metabolites that indicated the presence in the extracts. The best IC50 value was presented by ethyl acetate extracts (384,86 ppm) with 38.78% for 50 ppm, while IC50 values of n-hexane, methanolic, dicloromethane extracts were 410.12, 677.76 and 685.08 ppm, respectively. Keywords: Eucheuma spinosum, phytochemical analysis, radical scavenging activity

The Comparison of Optimum Conditions for Lead (Pb) Analysis Method using DITHIZONE and EDTA Complex in Seaweeds (Eucheuma spinosum)

The comparison of optimum conditions for lead (Pb) analytical method using dithizone and EDTA complexes in Eucheuma Spinosum (Eucheuma Sp.) was measured using a standard addition method, where the standard solution of Pb2+ was added to the sample to reduce noise. Additionally, UV-Vis spectrophotometer was used with dithizone and EDTA complexes in Eucheuma Spinosum, where Pb2+ ions in both complexes were measured. Both complexes were first developed to determine the optimal pH that would measure Pb2+ level in Eucheuma Spinosum. The most favorable pH level for such measurement was pH 8, at which pH activity was most stable, and the most favorable complex was dithizone complex, with a regression value closer to one than that of EDTA complex.

Physicochemical, Physical Characteristics and Antioxidant Activities of Three Edible Red Seaweeds (Kappaphycus alvarezii, Eucheuma spinosum and Eucheuma striatum) from Sabah, Malaysia

Kappaphycus alvarezii (KA), Eucheuma spinosum (ESp) and Eucheuma striatum (Est are tropical red seaweeds taken from Kunak, Sabah, contain essentials source of bioactive compounds to produce variety of functional foods. This study was intended to investigate the physicochemical, physical properties and antioxidant activities related to these edible seaweeds. Physicochemical properties value of swelling capacity (SWC) and oil retention capacity (ORC) in KA species showed the highest value (p<0.05) compared to ESp and ESt, and water retention capacity (WRC) in ESp species was significantly different than KA and ESt (p<0.05). As in physical properties, ESp exhibited higher in moisture content and opacity than KA and ESt. KA showed the highest water solubility (p<0.05) which associated to its carrageenan compound. The antioxidant activities; DPPH and TEAC assay with total phenolic content (TPC) of three seaweed species indicated that KA displayed the highest TPC (19.17±0.04 mg GAE/g DW) and the lowest radical scavenging activity in both TEAC and DPPH assays. Hence, the findings disclose the physical and physiochemical properties and antioxidant values of these seaweeds application as new information and potential antioxidant sources in foods manufacturing commodities.

Physicochemical, physical characteristics and antioxidant activities of three edible red seaweeds (Kappaphycus alvarezii, Eucheuma spinosum and Eucheuma striatum) from Sabah, Malaysia

Kappaphycus alvarezii (KA), Eucheuma spinosum (ESp) and Eucheuma striatum (Est are tropical red seaweeds taken from Kunak, Sabah, contain essentials source of bioactive compounds to produce variety of functional foods. This study was intended to investigate the physicochemical, physical properties and antioxidant activities related to these edible seaweeds. Physicochemical properties value of swelling capacity (SWC) and oil retention capacity (ORC) in KA species showed the highest value (p<0.05) compared to ESp and ESt, and water retention capacity (WRC) in ESp species was significantly different than KA and ESt (p<0.05). As in physical properties, ESp exhibited higher in moisture content and opacity than KA and ESt. KA showed the highest water solubility (p<0.05) which associated to its carrageenan compound. The antioxidant activities; DPPH and TEAC assay with total phenolic content (TPC) of three seaweed species indicated that KA displayed the highest TPC (19.17±0.04 mg GAE/g DW) and the lowest radical scavenging activity in both TEAC and DPPH assays. Hence, the findings disclose the physical and physiochemical properties and antioxidant values of these seaweeds application as new information and potential antioxidant sources in foods manufacturing commodities.

PENGARUH PENAMBAHAN BAYAM MERAH (Amaranthus tricolor L.) TERHADAP KAPASITAS ANTIOKSIDAN DAN SIFAT SENSORI NORI RUMPUT LAUT (Eucheuma spinosum)

This study aims to determine the antioxidant capacity and sensory properties of the produced seaweed Eucheuma Spinosum and red spinach Amaranthus tricolor L. The observations made included the antioxidant activity test, hedonic test and water content. The results showed that the moisture content of nori seaweed and red spinach ranged from 15.83-17.66%. The best water content was found in treatment A which had the lowest water content value of 15.83%. In the hedonic test the formulations of the two samples of seaweed and red spinach had no significant effect on the hedonic test on the appearance, color, taste, aroma and texture values with overall acceptance, namely like. The antioxidant capacity of nori Eucheuma Spinosum and red spinach is very weak because the IC50 value is greater than 200 ppm with nori IC50 nori A 38309 ppm, while nori B has an IC50 of 534.36 ppm.

Application of macroalgal biomass derived biochar and bioelectrochemical system with Shewanella for the adsorptive removal and biodegradation of toxic azo dye

The present study aimed towards adsorptive removal of the toxic azo dye onto biochar derived from Eucheuma spinosum biomass. Characterization of the produced biochar was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). Eucheuma spinosum biochar (ES-BC) produced at 600 °C revealed a maximum adsorption capacity of 331.97 mg/g towards reactive red 120 dye. The adsorption data fitted best to the pseudo-second order kinetics (R2 > 0.99) and Langmuir isotherm (R2 > 0.98) models. These adsorption models signified the chemisorption mechanism with monolayer coverage of the adsorbent surface with dye molecules. Furthermore, the adsorption process was mainly governed by electrostatic interaction, ion exchange, metal complexation, and hydrogen bonding as supported by the solution pH, FTIR, XPS, and XRD investigation. Nevertheless, alone adsorption technology could not offer a complete solution for eliminating the noxious dyes. Therefore, the bioelectrochemical system (BES) equipped with previously isolated marine Shewanella marisflavi BBL25 was intended for the complete remediation of azo dye. The BES II demonstrated highest dye decolorization (97.06%) within 48 h at biocathode where the reductive cleavage of the azo bond occurred. Cyclic voltammetry (CV) studies of the BES revealed perfect redox reactions taking place where the redox mediators shuttled the electrons to the dye molecule to accelerate the dye decolorization. Besides, the GC-MS analysis revealed biotransformation of the dye into less toxic metabolites as tested using a phyto and cytogenotoxicity.

Preliminary study of cultivated algae from South Sulawesi as antibacterial agent against fish pathogenic bacteria

The way to prevent or treating bacterial diseases outbreaks with drugs or chemicals is the one of main solutions to solve the problems in aquaculture. The use of antibacterial agents has increased significantly in aquaculture practices, since the antibiotics used in both human as well as veterinary medicines have been tried experimentally to treat bacterial infections of fish. However, the evolving resistance of fish pathogenic bacteria to existing antibiotics has necessitated development of new alternatives. In the last three decades the discovery of metabolites with biological activities from algae has increased significantly. In this study, sixteen extracts from four algae of genus Eucheuma were tested by in-vitro against five pathogenic bacteria (Aeromonas salmonicida, Aeromonas hydrophila, Pseudomonas anguilliseptica, Vibrio anguillarum and Yersinia ruckeri). The algae were extracted in Soxhlet apparatus using solvents with increased polarity (hexane, dichloromethane, methanol and water) for 24 h. The extract solutions were then evaporated and liophilized before using for the antibacterial test with agar diffusion method. The results revealed that three of four extracts (hexane, dichloromethane and water) were active against all pathogens, while methanol did not. The highest activity was shown by water extract, followed by the hexane and the dichloromethane extracts with lower activities. The water extract of Eucheuma spinosum had a broad activity since it was active against four of five pathogenic strains. Vibrio anguillarum and Pseudomonas anguillaseptica were the two most susceptible pathogens, while the most resistant was presented by Aeromonas hydrophila. The screening results confirm that algae were potential to be developed as a source of antibacterial compounds or as a health-promoting food for aquaculture.

Feeding preference and growth response of early adults abalone, Haliotis squamata on some macroalgae

Abstract. Yusup DS, Mahardika IG, Suarna IW, Giri INA. 2020. Feeding preference and growth response of early adults abalone, Haliotis squamata on some macroalgae. Biodiversitas 21: 4369-4375. Study on early adult Haliotis squamata fresh feed has evaluated some macroalgae, however, a study on Enteromorpha sp., Halymenia sp., and Hypnea sp. have not been carried out. This study was proposed to evaluate the feeding preference (feed response and feed intake) and the growth performance of early adult H. squamata on some macroalgae. Seven species of macroalgae were evaluated as unpair feeding choice and the experiment design employed was completely randomized design. The results showed that H. squamata responded variously to the seven macroalgae species and the food deprivation (fasting) data showed mounting response to all macroalgae. Ulva lactuca and Enteromorpha sp. were the most responded which up to four times higher compared to the least responded i.e. Halymenia sp. and Sargassum sp. The highest to the lowest palatable feed intake (FI) were Gracillaria sp, Eucheuma spinosum, Ulva lactuca, Halymenia sp., Enteromorpha sp., Sargassum sp. and Hypnea sp. respectively. The first four palatable macroalgae resulted in various growth responses of H. squamata. Except for Halymenia sp., the feed intake (FI) rate showed an opposite linear correlation to growth response and FCR. The daily growth rate (g/day) was Ulva lactuca (0.104), Enteropmorpha sp. (0.085), Gracillaria sp. (0.084), and Halymenia sp. (0.016). &#x0D;

Microwave-assisted depolymerization of carrageenans from Kappaphycus alvarezii and Eucheuma spinosum: Controlled and green production of oligosaccharides from the algae biomass

Algae biomass is nowadays considered as a unique reservoir of a huge variety of different molecules, such as lipids, carbohydrates, proteins and secondary metabolites, awaiting development in various fields. In particular, the valorization of the algae polysaccharide content is still in its infancy and intense research activity is starting to appear. Oligosaccharides with defined molecular weight and structures are extremely interesting for different applications such as plant biostimulation or biopesticide. Oligosaccharide are often prepared in medium to large scale upon chemical-based hydrolysis reactions from the extracted polysaccharides in harsh conditions (temperature and pH), leading to the loss of the fragile groups such as the sulfate functions in carrageenans. In the present work, microwave-based hydrolysis, as a green chemistry method, is optimized to produce bioactive oligosaccharides from carrageenans. Microwave hydrolysis process is first optimized on a commercially available carrageenan and further applied on carrageenans extracted from two algae, namely Kappaphycus alvarezii or Eucheuma spinosum that are produced in large quantities in the world and have a high content of carrageenans. We also develop a complete set of characterization methods, i.e. size exclusion chromatography, reducing sugar and residual sulfate determination and mass spectrometry, to perform the follow-up of the hydrolysis reaction. We here demonstrate that fast (5 min) and controlled hydrolysis of carrageenans can be achieved in pure water under microwave activation, while preserving the nature of the active sulfate groups (>95%).

The Effect of Different pH in Extraction Process Against Physicochemical Properties of Refined Iota Carrageenan from Eucheuma spinosum Seaweed.

Gelatin is a simple protein obtained from the partial hydrolysis of collagen from the skin, bones, joints and connective tissue of animals. One potential material for the manufacture of gelatin is fish bone milkfish (Chanos chanos). Gelatin derived from fish bones with acid process is able to change the triple helix collagen fibers into a single chain, whereas the solvent base only produce double chain. Demineralization of bone or fish skin should use a weak acid is acetic acid, because when using strong acids will produce a strong scent and color gelatin becomes dark. This study aims to determine the effect of the use of acetic acid to the production of fish bone gelatin and the concentration of acetic acid is necessary to produce gelatin with physical and chemical properties of the best. This study uses a Completely Randomized Design (CRD) with four treatments and five replications. The treatments used in this study is the concentration of acetic acid 2%, 4%, 6% and 8%. Based on the research, it was found that the acetic acid solvent effect on the value of the yield and gel strength, but has no effect on the pH value and viscosity. Acetic acid concentration 8% give 4.102% yield value; pH value (acidity) 4.98; 134.313 bloom gel strength and viscosity of 3.6 cP. FTIR analysis results indicate that the fish bone gelatin produced from this research have the same functional group with commercial gelatin.

Removal of Mn (II) from aqueous environment using Eucheuma spinosum

Eucheuma spinosum is one of the seaweed species that can be found abundantly in Takalar Regency. The biomass of this seaweed has been used to remove Mn (II) ion from the aqueous solution via the adsorption process using E. spinosum. The adsorption of Mn (II) ion was studied in various contact time, pH and concentration. An Atomic Absorption Spectrophotometer (AAS) was an instrument used to determine the amount of ion before and after adsorption. Langmuir and Freundlich’s equations were used to study the adsorption isotherms of the ion. The results showed that the optimum time obtained was 20 minutes and the optimum pH was 4. The Freundlich isotherm fitted the adsorption of ion Mn (II) using E. spinosum with the capacity (Qo) of 4.13 mg/g. The functional group involved in biosorption of Mn (II) metal ions was hydroxyl (-OH) groups.

Bioactivities of red seaweed extracts from Banten, Indonesia

Red seaweed has many advantages and can be utilized for cosmetics and pharmaceutical products for its rich bioactive content such as R-Phycoerythrin and phenols. This study were aimed to determine the R-phycoerythrin and phenolic contents, also the bioactivities of red seaweed extracts from Indonesia. The samples of Eucheuma sp., Gelidium sp., Eucheuma spinosum, Halymenia sp., and Rhodopeltis sp. were extracted by maceration method with distilled water (ratio 1:2, w/v) for 24 hours at cold temperature. The R-phycoerythrin content was determine by UV/VIS spectrophotometry at λ 455, 565, and 592 nm. Total Phenolic Content (TPC) was determined using Folin-Ciocalteu method. The antioxidant and antityrosinase were determined using Ferric Reducing/Antioxidant Power (FRAP) and mushroom tyrosinase assays. The highest yield of extract (2.73%, w/w) and R-PE (0.1056 mg/mL) were obtained from Halymenia sp., with highest phenolic content 8.79±1.21 GAE/mg, as well as in Eucheuma sp. (7.05±0.87 GAE/mg, p > 0,05). Halymenia sp. and Eucheuma sp. extracts showed antioxidant content of 19.40±0.37 and 19.08±0.66 AA mg/g, with tyrosinase enzymes of 40.09±2.01% and 41.36±3.8 % (1,000 ppm). Thus, Eucheuma sp. and Halymenia sp. extracts have high potential activities, while Halymenia sp. was potentialy used as natural colorant for cosmeticals and nutraceutical.

Cultivated seaweed carbon sequestration capacity

The rising of the earth’s temperature and climate change have attracted the attention of many scientists and environmental experts. One of the main strategies being proposed to minimize the acceleration of the earth’s temperature is to increase the potential of carbon sequestration from the atmosphere by taking advantage of the ability of plants, including algae, to utilize carbon dioxide in photosynthetic processes. This study aimed to estimate the carbon sequestration capacity and total carbon sequestration of macroalgae (seaweeds) commonly used in mariculture or in brackish-water pond (tambak) aquaculture. The study was conducted in August 2018 in South Sulawesi Province, Indonesia Carbon sequestration was estimated using the oxygen exchange method. Three maricultured seaweeds (Kappaphycus alvarezii green and brown strains and Eucheuma spinosum) and two pond-cultured seaweeds (Gracilaria verrucosa and Caulerpa racemosa) were studied. Thallus sections weighing 2.46-4.91 g were inserted into clear bottles (270 mL) filled with seawater and incubated for 3 hours (09.00-12.00), with 5 replicates for each seaweed. The bottles were attached to the seaweed culture lines (maricultured seaweeds) or placed in the ponds (pond-cultured seaweeds). Bottles filled with ambient water (containing phytoplankton) were used as controls. After 3 hours, titration was used to measure the oxygen exchange in each bottle, and the results converted into carbon sequestration. Seaweed productivity ranged from 0.660-11.997 mgCO2/gbk/hour with the lowest sequestration by K. alvarezii green strain and the highest by E. spinosum. Carbon sequestration was estimated at 57.64 tons CO2/ha/year for maricultured seaweed and 12.38 tons CO2/ha/year for pond-cultured seaweeds. The total annual carbon sequestration from seaweed cultivation in South Sulawesi was estimated at 2,656,625 tons CO2/year from mariculture and 621,377 tons CO2/year from pond culture.

Bioplastics synthesis based on sorghum–Eucheuma spinosum modified with sorghum stalk powder

In this study, a bioplastic was produced by addition of filler and plasticizer. Sorghum stalk powder was selected as a filler and glycerol as plasticizer. The effects of filler and plasticizer concentration on physical and mechanical characteristics of the bioplastics were observed. In the bioplastic production, the amount of sorghum stalk powder varied from 0.25 to 1 g, and glycerol concentration was varied from 5 to 20%. On the other hand, the amount of Eucheuma spinosum, as a fiber, and sorghum starch as a matrix remained constant. The bioplastic production has conducted by stirring the starch, fiber, filler, and glycerol for 35 minutes at 95°C and 375 rpm. The mixture was dried at 50°C for 8 hours. The best physical and mechanical characteristics of the product were obtained from the formulation consisting 0.5 g of filler and 10% of plasticizer concentration. The bioplastic itself had 21.265 MPa of tensile strength, 4.467% of elongation, 498.463 MPa of Young’s Modulus, 0.95 g/cm3 of density, and 21.265% of water uptake which are in the range of commercial HDPE plastic characteristics.