Ulva Reticulata Research Articles

THE EFFECTIVENESS OF GREEN SEAWEED (Ulva reticulate) ANTIBACTERIAL COMPOUND EXTRACT ON THE BACTERIA Vibrio parahaemolyticus

Green seaweed (Ulva reticulata) is found in many parts of Indonesia. The potential of green seaweed is not widely known to the public, even though it is considered a parasite on other types of seaweed. The purpose of this study was to determine the antibacterial compounds contained in green seaweed and their effectiveness against Vibrio parahaemolyticus bacteria. Green seaweed was extracted by maceration method and then qualitative and quantitative tests were carried out. After that, the minimum inhibitory concentration test was carried out and continued with the minimum bactericidal concentration test and the inhibition test with 5 treatments and 3 replications. The data from the qualitative and quantitative test of seaweed, the minimum inhibitory concentration and the minimum bactericidal were analyzed descriptively, while the data from the inhibition zone test was analyzed statistically by ANOVA. The results of qualitative and quantitative tests showed that green seaweed contained flavonoids (6.4909 mg/g), tannins (70.7500 mg/g) and saponins (443.7286 mg/g). The results of the minimum inhibitory concentration test showed that the concentration of 3.125% was the minimum concentration to inhibit bacterial growth. In the inhibition test, it can be seen that P4 (6%) is the best treatment. The results of statistical analysis show that the treatments given are significantly different, except that P4 (6%) and P5 (7,5%) are not significantly different. From this study it can be concluded that green seaweed extract is effective in inhibiting the growth of Vibrio parahaemolyticus bacteria.

Chemical composition, antimicrobial, and antioxidant activity of Ulva reticulata seaweed extracted with different solvents

Abstract. Djoh EFK, Meiyasa F, Ndahawali S, Tarigan N. 2024. Chemical composition, antimicrobial, and antioxidant activity of Ulva reticulata seaweed extracted with different solvents. Biodiversitas 25: 2943-2949. Ulva reticulata Forsskal, 1775 is a green seaweed that has the potential to be developed in food, nutraceuticals, pharmaceuticals, and nutraceuticals; thus, studying the chemical composition and antimicrobial and antioxidant activities is necessary. Ulva reticulata samples were obtained from the waters of Hambuang, Haharu Sub-district, East Sumba Island, dried in the sun for three days, and floured for chemical composition analysis. In addition, water quality was tested regarding pH, Dissolved Oxygen (DO), and temperature in the Hambuang Waters. Ulva reticulata simplisia was extracted with three different solvents, namely methanol, ethyl acetate, and chloroform, and then tested for antimicrobial activity against Staphylococcus aureus Rosenbach, 1884 and Escherichia coli E and antioxidant activity. The results showed that the water quality of Hambuang was relatively good according to SNI standards with a pH value of 7.52, DO of 6.23 mg/L, and temperature of 31.30°C. Furthermore, the chemical composition of U. reticulata had a moisture content of 12.31%, ash of 23.32%, lipid of 3.04%, protein of 12.93%, and carbohydrate of 48.40%. The antioxidant activity of U. reticulata extract with methanol, ethyl acetate, and chloroform solvents were 235.31, 174.72, and 146.14 µg/mL, respectively. Furthermore, U. reticulata extract with methanol, ethyl acetate, and chloroform solvents had antimicrobial activity against S. aureus of 39.59, 33.81, 14.94 mm, and E. coli of 15.94, 17.93, 12.69 mm, respectively. Therefore, U. reticulata has the potential to be used as an ingredient in the food, nutraceutical, pharmaceutical, and cosmeceutical industries applications.

Regulatory potential of a xylated rhamnoglycan from Ulva reticulata on inflammatory cytokines

Regulatory potential of a xylated rhamnoglycan from Ulva reticulata on inflammatory cytokines

The Potency of Ulva reticulata as Natural Flavoring to Prevent Hypertension

The Potency of Ulva reticulata as Natural Flavoring to Prevent Hypertension

Phycosynthesis and characterization of silver nanoparticles produced by biological reduction method using Ulva reticulata Forssk

Phycosynthesis and characterization of silver nanoparticles produced by biological reduction method using Ulva reticulata Forssk

Characterization of a Bioplastic Product from the Ulva reticulata (Ribbon Sea Lettuce) Extract

Humans have a strong reliance in using petroleum-based plastics which take several decades to degrade and cause a lot of environmental problems such as pollution. This study intended to develop bioplastics from Ulva reticulata (Ribbon sea lettuce) and to determine the bioplastic’s physicochemical properties. The sample was collected in Allen, Northern Samar, Philippines, water samples were also collected. After the extraction, development of bioplastic from the sample extract commenced. The developed bioplastic underwent several test to check the stability of the product – its includes physicochemical analysis, tensile strength, thickness, moisture content, and soil degradation test. The Ribbon sea lettuce bioplastic solution was slightly acidic. The seaweed bioplastic have an average thickness of 0.30mm. The Ribbon sea lettuce bioplastic sample was both insoluble in the three solvents. The sample bioplastic can handle an average load of 55.12g. An average moisture content of 51.534% have been observed in the three trial of the seaweed bioplastic sample. The seaweed bioplastic sample naturally degraded during the soil biodegradation test and have lost an average weight percentage of 82.05% after 21 days of being buried in soil. The results showed that the seaweed bioplastic has a potential as an alternative to the non-biodegradable plastic and can be used in agricultural, industrial and economic purposes.

Inventory of Seaweeds in Selected Municipalities in the Balicuatro Area of the Province of Northern Samar, Philippines

Seaweeds or marine macroalgae is one of the marine resources that are understudied in the province of Northern Samar, the province have twenty-four (24) municipalities and twenty (20) of them have coastal zone which is ideal for marine researches as well as for aquaculture. This study is focused on the present seaweeds in the three (3) selected municipalities in Balicuatro area in the province of Northern Samar. A total of ninety-four (94) taxa were collected/ found in the three (3) sampling sites. Lavezares got the greatest number of seaweeds with sixty (60) taxa, followed by Biri with fourty-four (44), and the least was in Allen with thirty-four (34) species. Chlorophyta have thirty-nine (39) species which constitute for 39.36% of the total identified seaweeds, followed by thirty-four (34) red seaweeds (36.17%), and, lastly, Brown macroalgae with only twenty-three (23) species which accounts for 24.47%. The most common marine macroalgae in all sampling sites were: Hormophysa cuneiformis which was found in ten (10) sampling sites, followed by Halimeda macroloba, Ulva reticulata, and Sargassum oligocystum which were found in ten (10) sampling sites. In terms of environmental parameters, temperature and salinity of all sampling sites were tested to be within the normal range during the collection period based on established threshold limit. However, in terms of pH, it was detected that two (2) barangays/ sampling sites in Lavezares, namely: Balicuatro and San Juan which only had 7.2 and 7.4 which is below the threshold limit range of seawater pH which is 7.5-8.5. In terms of substrate, rocky substrate is common to all sampling sites which indicates that hard substratum is preferable for the growth, adaptation, and survival of seaweeds.

The Effect of Fermentation Time, pH and Saccharomyces Cerevisiae Concentration for Bioethanol Production from Ulva Reticulata Macroalgae

Research has been carried out on the effect of pH, fermentation time and yeast concentration on bioethanol production through hydrolysis using a CEM (Ceramic Elekctromagnetic Microwave) synthesizer and bioethanol production from Ulva reticulata seaweed. Ulva reticulata seaweed contains carbohydrates in the form of heteropolysaccharides such as glucose, arabinose, ramnose and xylose which are very abundant and suitable for conversion into bioethanol because the people of Timor Island do not use them as food. The carbohydrate content of Ulva reticulata seaweed can be converted into hexose and pentose sugars (glucose, arabinose, ramnose and xylose) through hydrolysis using 3 types of acid catalysts, namely hydrochloric acid (HCl), sulfuric acid (H2SO4) and nitric acid (HNO3). Fermentation was carried out with S. cerevisiae concentration variation of 6; 8; 10; 12 % (v/v) and fermentation time variation of 3; 5; 7; 9 days and a pH variation of 4; 4.5; 5; 5.5 at a temperature of 30 °C. Reducing sugar characterization used the Dinitrosalicylic acid (DNS) reagent, sample surface texture analysis was carried out using Scanning Electron Microscopy (SEM) and ethanol characterization used Gas Chromatography-Flame Ionization Detector (GC-FID). The results of surface texture analysis before and after hydrolysis experienced significant changes. Optimal conditions for hydrolysis of Ulva reticulata seaweed using sulfuric acid (H2SO4) combined with a CEM synthesizer at an acid concentration of 3 % (v/v) with irradiation power of 200 watts for 50 min at a temperature of 150 °C, produced reducing sugar of 97.06 g/L. The results of GC-FID analysis indicated that bioethanol concentration obtained at optimal conditions of pH 4.5 was 42.32 %, S. cerevisiae concentration was 12 % with a bioethanol content of 42.53 % at a fermentation time of 5 days. This research is expected to provide information for researchers and industry to overcome world energy problems and environmental pollution through Ulva reticulata waste. HIGHLIGHTS The results of surface texture analysis before and after hydrolysis experienced significant changes. Optimum conditions for hydrolysis of Ulva reticulata seaweed using sulfuric acid (H2SO4) combined with a CEM synthesizer at an acid concentration of 3 % (v/v) with irradiation power of 200 watts for 50 min at a temperature of 150 °C, producing reducing sugar of 97.06 g /L. GRAPHICAL ABSTRACT

Potential use of phytochemical from ethanolic extract of green seaweed Ulva reticulata in aquaculture

Abstract. Tarigan N, Sudrajat AO, Arfah H, Alimuddin A, Wahjuningrum D. 2023. Potential use of phytochemical from ethanolic extract of green seaweed Ulva reticulata in aquaculture. Biodiversitas 24: 6868-6879. Ulva reticulata is green seaweed with potential phytochemical properties in the aquaculture sector. Therefore, this study aims to determine phytochemical components and evaluate the toxicity of Ulva reticulata ethanolic extract on aquatic animals. The primary constituents in the sample were extracted using the maceration method with 96% ethanol. The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, while toxicity level was determined using the Brine Shrimp Lethal Test (BSLT) method at concentrations of 0, 10, 100, 300, 500, 1000, and 2000 mg L-1. The results showed that Ulva reticulata ethanolic extract was qualitatively composed of alkaloids, flavonoids, saponins, tannins, phenols, and steroids with mid (++), low (+), low (+), low (+), low (+), and mid (++) activity levels, respectively. Based on quantitative analysis, the sample was composed of sitosterol (19.01 mg g-1), stigmasterol (35.00 mg g-1), saponins (17.04 mg g-1), flavonoids (82.16 mg QE 100 g-1), total phenols (144.00 g QE 100 g-1), and tannins (49.03 mg g-1). Furthermore, Ulva reticulata ethanolic extract had a strong antioxidant level with a 50% inhibitory concentration (IC50) of 53.00 ppm. The toxicity test showed that the 50% lethal concentration (LC50) of the sample was 481.86 mg L-1. These results showed that Ulva reticulata ethanolic extract was a non-toxic material with a high potential for phytochemical properties that could be beneficial for fish growth, reproduction, and health.

Biological activities of macroalgae in the Moudulung waters: bioactive compounds and antioxidant activity

This study aimed to determine the bioactive compounds and antioxidant activity of macroalgae in Moudolung Waters. The bioactive compounds in seven samples of macroalgae were extracted with methanol. Analysis of macroalgae bioactive compounds was carried out qualitatively by determining the presence of bioactive compounds including alkaloids, flavonoids, saponins, tannins, phenol hydroquinone, and steroids/ terpenoids. antioxidant activity was carried out using the DPPH (2,2-diphenyl-1-picrylhydrazyl-hydrate) method. Data were analyzed descriptively using Microsoft Excel and all data are expressed as mean. The results showed that these seven macroalgae species have bioactive compounds such as alkaloids, flavonoids, saponins, tannins, phenol hydroquinone, and steroids/terpenoids which function as antioxidants. The highest antioxidant activity was the MA6 (Turbinaria ornate) followed by MA1 (Hormopysa triquetra), MA4 (Ulva flexuosa syn. Enteromorpha flexuosa), MA5 (Eucheuma spinosum), MA2 (Sargassum muticum), MA3 (Gracilaria corticate), and MA7 (Ulva reticulata) were 75.25 mg/mL, 90.31 mg/mL, 134.52 mg/mL, 200.22 mg/mL, 216.91 mg/mL, 259.16 mg/mL, and 270.42 mg/mL, respectively. The results suggested that Turbinaria ornate and Hormopysa triquetra could be used as an important substitute for functional ingredients in foods and pharmaceuticals or nutraceuticals.

The Optimization of Initial Treatment of Seaweed Ulva reticulata Using CEM Synthesizer Method for Bioethanol Production

Research has been carried out on the optimization of initial treatment and hydrolysis using CEM microwave synthesizer and the production of bioethanol from Ulva reticulata seaweed. Optimization in the initial treatment was carried out by varying the concentration of HCl and H2SO4 (each in 1; 3; 5; and 7%), variations in time (30; 40; 50; and 60 minutes), temperature (100; 150; 200 and 250 °C), and electrical power (100; 150; 200; and 250 W). Fermentation was carried out anaerobically at 10% inoculum concentration and a production time of 6 days. Characterization of reducing sugar using DNS method and characterization of ethanol using GC-FID and HPLC. The results of the initial lignocellulosic analysis obtained the lignin content of 10.03%, cellulose 14.38% and hemicellulose 22.29%. After the initial treatment, the lignin content decreased to 3.86%, while cellulose increased to 24.50% and hemicellulose to 41.57%. The reducing sugar content produced using HCl is 97.10 g/L at optimum temperature 200 °C, for 60 minutes, using 7% concentration of HCl and 200 W of power, while the optimum reducing sugar content using H2SO4 is 76.40 g/L at optimum temperature 200 °C, time for 50 minutes, using 3% concentration of H2SO4 and 200 W of power. Production of bioethanol through fermentation and distillation processes obtained a bioethanol level of 43.89% (GC) or 18.89% (HPLC) for optimum conditions using H2SO4, whereas for optimum conditions using HCl, the bioethanol level is 44.29% (GC) or 18.09% (HPLC).

Identifikasi Makroalga yang Tersebar di Perairan Walakiri Sumba Timur

This study aims to identify macroalgae scattered in Walakiri waters. The method used in this study was to explore the entire coast of Walakiri. The samples which were then identified visually and morphologically include: color, thallus shape, serrations on the stems of each macroalgae sample and then matched to AlgaeBase: http://www.algaebase.org. The results showed that there were 3 classes of macroalgae with a total of 10 species including red algae (Eucheuma cottonii, Eucheuma spinosum, Achanthopora spicifera), brown algae (Padina australis, Sargassum vulgare, Sargassum cristaefolium, Sargassum polycystum), and green algae (Ulva reticulata, Halimeda micronesica, Codium Fragile). In addition, the water quality of Walakiri is good for macroalgae growth.

Biohydrogen production through energy efficient surfactant induced microwave pretreatment of macroalgae Ulva reticulata

Macroalgal biomass being rich in carbohydrates, proteins and lipids in their cell wall has been considered as the most efficient organic rich sources for biofuel (biohydrogen) production. In this study, Pluronic P-123-induced microwave pretreatment was applied to disintegrate the marine macroalgae biomass, Ulva reticulata. Microwave disintegration was done by varying the treatment time and microwave power from 0 to 40 min and 0.09 KW to 0.63 KW. A maximum chemical oxygen demand (COD) solubilization of 22.33% was achieved at a microwave power and time duration of 0.36 kW and 15 min. Chemical (Pluronic P-123, a mild surfactant) was combined with optimum microwave disintegration conditions to increase the solubilization efficiency and this combined pretreatment achieved a maximum COD solubilization of 31.02% at 10 min pretreatment time and 0.06 g per g TS of Pluronic P-123 dosage. The present study indicated that combination of surfactant with microwave pretreatment substantially improves the COD solubilization with reduced pretreatment -time than mono microwave pretreatment. An optimal hydrogen yield of 98.37 mL was achieved through this combined pretreatment. The biohydrogen data was modelled with Gompertz model and the kinetic parameters derived through this model implies that the calculated adjusted R squared values for all the samples lies between 0.95 and 0.99. This shows that the model fitted biohydrogen experimental values accurately. In addition, Pluronic P-123-induced microwave pretreatment was regarded as energy efficient and cost effective than microwave pretreatment alone with net energy production and a greater energy ratio of 504.38 kWh/Ton macroalgae and 1.2 when compared to microwave pretreatment alone (−2975.6 kWh/Ton macroalgae and 0.5).

Linking the ecological roles of Jania adhaerens and Ulva reticulata in seagrass meadows based on variations of tissue δ13C and δ15N

The capacity of macroalgae to absorb, hold, and release the relative amounts of carbon (C) and nitrogen (N) in its environment varies. C and N stable isotopes can be used to gain a better understanding of the ecosystem services of nutrient cycling by quantifying its usage in macroalgae. In this study, we conducted an in situ δ13C and δ15N tracer study of the macroalgae Ulva reticulata and Jania adhaerens in the seagrass meadows of Sungai Pulai estuary, Johor. Bulk tissues were labelled with enriched sodium bicarbonate (NaH13CO3) and ammonium chloride (15NH4Cl). Within 1 to 18 days post-enrichment, the macroalgae were measured for C N contents and stable isotope signatures. U. reticulata showed more bulk losses for excess 13C and 15N compared to J. adhaerens. J. adhaerens tended to retain greater %C and %N incorporated in its tissues. There was a clear distinction between the amount of C and N retained and lost in the tissues of each species. The amount of nutrients, especially C, that remained at the end of the experiment demonstrated that both macroalgae species are capable of short-term carbon sequestration, with implications for meadow-scale nutrient subsidies. Higher N uptake and retention in the biomass of the macroalgae, especially in U. reticulata, suggest their relatively high growth capacity. Understanding the C and N dynamics and loss rate of the whole plant provides an estimation of the nutrient uptake and retention capacity of the macroalgae. Such insights are important as a means to formulating steps in preserving the ecological balance of marine ecosystems.

Optimasi Proses Hidrolisis Rumput Laut Ulva Reticulata dengan Pelarut HNO3 untuk Produksi Bioetanol

One alternative to make biofuels and replace petroleum-based fuels is to convert non-food ingredients from Ulva reticulata seaweed into bioethanol. Seventy percent of the earth's surface is covered by microalgae and seaweeds that can be converted into bioethanol. Ulva seaweed contains 50.3% carbohydrates in the form of heteropolysaccharides such as glucose, arabinose, rhamnose and xylose. Optimization of the seaweed hydrolysis catalyzed by HNO3 using Microwave irradiation was done by varying acid concentration (1, 3, 5, 7%), hydrolysis time (30, 40, 50, and 60 minutes), and hydrolysis temperature (75, 100, 125, 150°C). Fermentation was carried out by varying inoculum concentrations (6, 8, and 10% (v/v)) for 5, 6 and 7 days at a temperature of 30°C and a pH of 4.5. Analysis of the surface texture of the sample was carried out by Scanning Electron Microscopy (SEM). The analysis of reducing sugars concentration was carried out using the dinitrosalicylate (DNS) method. Ethanol analysis was carried out by Gas Chromatography (GC). The results of SEM analysis showed that prior to hydrolysis, the surface morphology of the powder was still compact and intact. Whereas after being hydrolyzed with HNO3 it was seen that the surface texture of the powder suffered significant damage. The hydrolysis results showed that the optimum conditions during the pretreatment of U. reticulata powder was at acid concentration of 7%, reaction time of 50 minutes, reaction temperature of 150°C and 250 watts of power which gave hydrolysate with reducing sugar concentration of 86.5 g/L. Fermentation of the hydrolysate using yeast Saccharomyces cerevisiae produced bioethanol with concentration of 37.2% as analyzed using a gas chromatograph.

Phytochemical Compounds and Antibacterial Activity to Escherichia coli of Green Macro Algae

Escherichia coli is a bacteria found in the large intestine of humans as a normal flora. It’s unique because it can cause primary infection in the intestine such as diarrhea in children. Diarrhea sufferers use drugs derived from chemicals and herbal plants. Furthermore seaweed as the marine biological resources it is important to examine to be an alternative treatment for diarrhea. An antibacterial alternative by development the use of seaweed. needs to be examine. Based on the description above, phytochemical compound of several types of green macro algae and its potential effect as antibacterial activity to inhibit the growth of E.coli bacteria it is necessary to examine, The type of seaweeds that use in this study are Ulva reticulata, Ulva lactuca and Caulerpa racemosa. The research results showed that phytochemcal compound of U. reticulata are terpenoid, phenolic, alkaloid. In U. lactuca are steroid, saponin, phenolic and alkaloid. Phytochemcal compound of C. racemosa are phenolic, flavonoid, alkaloid, and terpenoid. Type of green macro algae U. reticulata had the ability to inhibit the bacteria E.coli growth with a inhibition zone diameter about 6.0 mm U. lactuca about 10 mm, and C. racemosa about 12.0 mm.

Bioactivity Guided Study for the Isolation and Identification of Antidiabetic Compounds from Edible Seaweed-Ulva reticulata.

Managing diabetes is challenging due to the complex physiology of the disease and the numerous complications associated with it. As part of the ongoing search for antidiabetic chemicals, marine algae have been demonstrated to be an excellent source due to their medicinal properties. In this study, Ulva reticulata extracts were investigated for their anti-diabetic effect by examining its inhibitory effects on α-amylase, α-glucosidase, and DPP-IV and antioxidant (DPPH) potential in vitro and its purified fraction using animal models. Among the various solvents used, the Methanolic extract of Ulva reticulata (MEUR) displayed the highest antidiabetic activity in both in vitro and in vivo; it showed no cytotoxicity and hence was subjected to bioassay-guided chromatographic separation. Among the seven isolated fractions (F1 to F7), the F4 (chloroform) fraction exhibited substantial total phenolic content (65.19 μg mL-1) and total flavonoid content (20.33 μg mL-1), which showed the promising inhibition against α-amylase (71.67%) and α-glucosidase (38.01%). Active fraction (F4) was further purified using column chromatography, subjected to thin-layer chromatography (TLC), and characterized by spectroscopy techniques. Upon structural elucidation, five distinct compounds, namely, Nonane, Hexadecanoic acid, 1-dodecanol, Cyclodecane methyl, and phenol, phenol, 3,5-bis(1,1-dimethylethyl) were identified. The antidiabetic mechanism of active fraction (F4) was further investigated using various in vitro and in vivo models. The results displayed that in in vitro both 1 and 24 h in vitro cultures, the active fraction (F4) at a concentration of 100 μg mL-1 demonstrated maximum glucose-induced insulin secretion at 4 mM (0.357 and 0.582 μg mL-1) and 20 mM (0.848 and 1.032 μg mL-1). The active fraction (F4) reduces blood glucose levels in normoglycaemic animals and produces effects similar to that of standard acarbose. Active fraction (F4) also demonstrated outstanding hypoglycaemic activity in hyperglycemic animals at a dose of 10 mg/kg B.wt. In the STZ-induced diabetic rat model, the active fraction (F4) showed a (61%) reduction in blood glucose level when compared to the standard drug glibenclamide (68%). The results indicate that the marine algae Ulva reticulata is a promising candidate for managing diabetes by inhibiting carbohydrate metabolizing enzymes and promoting insulin secretion.

Uji Efektivitas Daya Antibakteri Ekstrak Alga Terhadap Pertumbuhan Bakteri Patogen Streptococcus Mutans

Background: Steptoccocus mutans is one of flora normal bacteria in the human body which can cause infections in the mouth cavity. Algae are plant-like organisms that may be found in a marine ecosystem. Recents studies have reported that algae contains numerous pharmacological activities compounds, such us: antibiotic, cytotoxic, antifungal, anti virus and antitumor. Purpose: this research aimed to know the antibacterial activity of algae extract against the growth of pathogen bacteria Streptococcus mutans. Methods: Algae were extracted by using aquades.The inhibition test was performed by agar diffusion method on Glucose Nutrient Agar (GNA) using three types of algae extracts: Eucheuma cottoni, Turbinaria decurrens and Ulva reticulata on the incubation period 1x24 and 2x24 hours at 37◦C. Data collection technique was based on the results of measuring the diameter of the inhibition zone (clear zone) for the growth of Streptococcus mutans bacteria using a caliper. The data obtained were analyzed using quantitative descriptive analysis methods. This data analysis was processed to see if there was a difference in antibacterial power from extract algae samples. Results: U. Reticulate algae extract formed a clear zone 11.2 mm in diameter at 1x24-hour incubation, and 10.3 mm at 2x24-hour incubation. T. deccurens formed clear zones 12.7 mm in diameter at 1x24-hour incubation, and 11.4 mm at 2x24-hour incubation. E. cottonii formed clear zones 10.1 mm in diameter at 1x24-hour incubation, and 9.3 mm at 2x24-hour incubation. Conclusion: Extracts of T. decurrens have the most potential in inhibiting the growth of pathogenic microbes of S. mutants.

Improving the biohydrogen production potential of macroalgal biomass through mild acid dispersion pretreatment

Macroalgae is becoming more popular as a viable and promising resource for the production of biofuels belonging to the third generation (i.e biofuels that are made from algae). The high ratio of carbohydrates and lipids, as well as the lack of lignin, make macroalgae a desirable feedstock for biofuel production. However, algal biomass must be pretreated before fermentation to make the carbohydrates trapped within the cell wall more accessible. An effective pretreatment method favors the hydrolysis of biomass and makes the substrates available for hydrogen production. In this study, Ulva reticulata was combinedly pretreated with a disperser and acid to effectively generate fermentative biohydrogen production. The disperser’s rotational speed of about 12,000 rotation per minute and input of specific energy of about 2500 Kilojoule/Kilogram of Total Solids with the dispersion duration of thirty minutes and maintaining the biomass at pH 5 with diluted sulphuric acid were optimized as the experimental parameters for the effective solubilization of the macroalgae. The experimental results displayed that the biohydrogen production increased by about 83 % at the optimized parameters compared to the untreated algal biomass. The combined pretreatment can efficiently disrupt the macroalgal structure leading to a rise in the concentration of organic matters such as SCOD (soluble chemical oxygen demand), proteins, and carbohydrates thereby enhancing the production of biohydrogen. The combined pretreatments yielded 60 mL/g COD of biohydrogen, whereas the biomass pretreated with a disperser alone and untreated macroalgae produced only 30 mL/g COD and 5 mL/g COD of biohydrogen, respectively. Thus, it is inferred that the sample pretreated with the homogenizer (disperser) and acid produced the most biohydrogen. In general, it can be concluded that a combination of disperser along with the addition of acid could be used as an efficient method for disrupting the structure of macroalgal biomass thereby enhancing the fermentative hydrogen production.

A novel conversion of marine macroalgal biomass to biofuel (biohydrogen) via calcium hypochlorite induced dispersion

Environmental pollution due to the consumption of non-renewable energy lead the search for alternative eco-friendly renewable fuel. The study details the biohydrogen production efficiency by potential macroalgal (Ulva reticulata) biomass improved by a disperser combined with calcium hypochlorite pretreatment technology. Calcium hypochlorite was added to decrease the surface energy of the medium induced by sole disperser pretreatment. Optimum condition for algal disperser treatment was 10,000 rpm with 30 min as dispersion time. The specific energy spent for the disintegration of the macroalgal biomass was 1231.58 kJ/kg TS. COD solubilization rate of 11.79% was attained with mechanical pretreatment whereas increased to 20.23% with combined pretreatment. Combination of disperser with calcium hypochlorite significantly reduced the specific energy input spent to 500 kJ/kg TS. The amount of organic materials such as carbohydrates, proteins and lipids released were 680 mg/L, 283 mg/L and 136 mg/L respectively. Thus, the combinative pretreatment with disperser rotor speed (10,000 rpm) for pretreatment time (12 min) and calcium hypochlorite dosage (0.1 g/g) derived as optimum condition for effective solubilization of macroalgal biomass. Biohydrogen production potential was maximum in the macroalgae pretreated with both disperser and calcium hypochlorite recorded highest yield (54.6 mL H2/g COD) compared to the macroalgae pretreated with disperser alone (31.7 mL H2/g COD) and untreated macroalgae (11.5 mL H2/g COD).