Green Alga Ulva Lactuca Research Articles

Properties of polysaccharides in several seaweeds from Atlantic Canada and their potential anti-influenza viral activities

To explore the polysaccharides from selected seaweeds of Atlantic Canada and to evaluate their potential anti-influenza virus activities, polysaccharides were isolated from several Atlantic Canadian seaweeds, including three red algae (Polysiphonia lanosa, Furcellaria lumbricalis, and Palmaria palmata), two brown algae (Ascophyllum nodosum and Fucus vesiculosus), and one green alga (Ulva lactuca) by sequential extraction with cold water, hot water, and alkali solutions. These polysaccharides were analyzed for monosaccharide composition and other general chemical properties, and they were evaluated for anti-influenza virus activities. Total sugar contents in these polysaccharides ranged from 15.4% (in U. lactuca) to 91.4% (in F. lumbricalis); sulfation level was as high as 17.6% in a polysaccharide from U. lactuca, whereas it could not be detected in an alikali-extract from P. palmaria. For polysaccharides from red seaweeds, the main sugar units were sulfated galactans (agar or carrageenan) for P. lanosa, F. lumbricalis, and xylans for P. palmata. In brown seaweeds, the polysaccharides largely contained sulfated fucans, whereas the polysaccharides in green seaweed were mainly composed of heteroglycuronans. Screening for antiviral activity against influenza A/PR/8/34 (H1N1) virus revealed that brown algal polysaccharides were particularly effective. Seaweeds from Atlantic Canada are a good source of marine polysaccharides with potential antiviral properties.

Induction of natural defence accompanied by salicylic acid-dependant systemic acquired resistance in tomato seedlings in response to bioelicitors isolated from green algae

Poly- and oligosaccharides isolated from the green algae Ulva lactuca were tested for their capacity elicitor of natural defences in tomato seedlings. After internodal infiltration of the bioelicitor solution in the midstem of tomato seedlings, the elicitor capacities were evaluated by determining the activity of phenylalanine ammonia-lyase (PAL) in the leaves located above and below the elicitation site. The results obtained showed that the crude extract of U. lactuca polysaccharides expressed an elicitor capacity of PAL activity in leaves. This expression level was similar and even higher than the ones due to other algae polysaccharides (carrageenan, laminarin and alginate). The crude extract of polysaccharides contained two polysaccharides, the glucuronan (unsulfated homopolymer) and the ulvan (sulfated heteropolymer). The glucuronan had no significant elicitor effect whereas the ulvan induced an elicitor capacity higher than that of the crude polysaccharidic extract. The desulfation of the ulvan caused a suppression of its elicitor capacity of PAL activity. The oligoulvans (sulfated β-Δ-(4,5)-oligorhamnoglucuronans, degree of polymerization average=2) and the oligoglucuronans (β-Δ-(4,5)-oligoglucuronans, degree of polymerization average=3) were prepared from the ulvan and the glucuronan using two specific enzymes a ulvan lyase and a glucuronan lyase, purified from the bacterial strain Ochrobactrum sp. PEC2. The treatment of tomato seedlings with the oligoulvans was accompanied by a strong stimulation of PAL activity, reaching a maximum activity of 2–2.5 times higher than that of the ulvan polymer. Although the oligoglucuronans expressed an elicitor capacity in PAL activity twice higher than that of the glucuronan polymer, its induction was less important than the oligoulvans. The high elicitor capacity of these saccharides seemed to be related to sulfate substituents and the rhamnose residues. The stimulation of PAL activity was accompanied by an increase of phenolic compounds content and an induction of salicylic acid in the leaves located above and below the elicitation site. The treatments of tomato seedlings with U. lactuca elicitors significantly reduced wilt development caused by Fusarium oxysporum f. sp. lycopersici. The percent of wilting and mortality after 45 days was markedly reduced when plants were treated with oligoulvans, respectively 44% and 54% compared to the control plants.The whole of these results showed clearly those U. lactuca elicitors, particularly the ulvan and the oligoulvans, induced in tomato seedlings the stimulation of natural systemic defences accompanied by a systemic acquired resistance that seems to be salicylic acid-dependent.

Biosorption of Cu(II), Zn(II), Cd(II) and Pb(II) by dead biomasses of green alga Ulva lactuca and the development of a sustainable matrix for adsorption implementation

Many industries have high heavy metals concentrations in their effluents that should be treated before disposal in drains or natural watercourses. When adsorption process is evaluated to generate and implement an efficient, economical and sustainable method suitable for heavy metals removal from contaminated effluents, it is necessary to develop an experimental setup that contains the adsorbent.Ulva lactuca, a marine green alga, was studied as a natural biosorbent for heavy metals at acid pH conditions. Adsorption experiments were carried out in glass columns and in batch where the alga was suspended or fixed in an agar matrix.Langmuir and Freundlich models were applied to the experimental results. Langmuir model best describes the adsorption isotherms in all analyzed cases. The adsorption capacity increases with pH. Kinetic studies demonstrate that, in most studied cases, the adsorption follows a pseudo second order kinetics model.Removal efficiencies of the biomaterial supported in agar or fixed in columns were: fixed in columns>suspended in batch mode>fixed in agar.Finally, the effect of the presence of two sorbates, Cd and Pb, in the solution was measured and results demonstrate that adsorption of both metals are diminished by co/adsorption.

BIOSORPTION OF Cd(II) FROM AQUEOUS SOLUTION ON MARINE GREEN ALGAE BIOMASS

In this study the marine green algae (Ulva lactuca sp.) was used as low-cost sorbent for the removal of Cd(II) ions from aqueous solution. The biosorption of Cd(II) on marine green algae was investigated as a function of initial solution pH, sorbent dose, initial Cd(II) concentration and contact time, in batch experiments at room temperature (200.5C). About 0.2 g of marine green algae biomass was found to be enough to remove 85% of 67.57mg/L Cd(II) from 25 mL aqueous solution in 30 min, at initial solution pH of 5.0, considered to be optimum. The Langmuir and Freundlich isotherm models were used to describe the biosorption equilibrium of Cd(II) on marine green algae biomass. The experimental data gave good fit with Langmuir isotherm model, and the parameters deduced from this model agree with the conditions of favourable biosorption. The pseudo-first order and pseudosecond order kinetic models were used to correlate the experimental data. The kinetics parameters were determined for both models, and the pseudo-second order equation was found to be more suitable. The analysis of FT-IR spectra suggest that amido, hydroxyl, C–O and C=O could interact with Cd(II) ions, during of biosorption process.

Feeding preferences of mesograzers on aquacultured Gracilaria and sympatric algae

While large grazers can often be excluded effectively from algal aquaculture operations, smaller herbivores such as small crustaceans and gastropods may be more difficult to control. The susceptibility of three Gracilaria species to herbivores was evaluated in multiple-choice experiments with the amphipod Ampithoe ramondi and the crab Acanthonyx lunulatus. Both mesograzers are common along the Mediterranean coast of Israel. When given a choice, the amphipod preferred to consume Gracilaria lemaneiformis significantly more than either G. conferta or G. cornea. The crab, however, consumed equivalent amounts of G. lemaneiformis and G. conferta, but did not consume G. cornea. Organic content of these algae, an important feeding cue for some mesograzers, could not account for these differences. We further assessed the susceptibility of a candidate species for aquaculture, G. lemaneiformis, against local algae, including common epiphytes. When given a choice of four algae, amphipods preferred the green alga Ulva lactuca over Jania rubens. However, consumption of U. lactuca was equivalent to those of G. lemaneiformis and Padina pavonica. In contrast, the crab showed a marked and significant preference for G. lemaneiformis above any of the other three algae offered. Our results suggest that G. cornea is more resistant to herbivory from common mesograzers and that, contrary to expectations, mixed cultures or epiphyte growth on G. lemaneiformis cannot reduce damage to this commercially appealing alga if small herbivores are capable of recruiting into culture ponds. Mixed cultures may be beneficial when culturing other Gracilaria species.

Nitrogen uptake and growth by the opportunistic macroalga Ulva lactuca (Linnaeus) during the internal tide

To determine if an opportunistic macroalga could increase its tissue nitrogen content in response to nutrient pulses forced by the internal tide, independent samples of the green alga Ulva lactuca (Linnaeus), previously cultured in nutrient-poor tanks, were outplanted in the nearshore ocean for 12 h deployment periods (8 daylight periods, 7 night periods), at three different depths (1, 5, and 10 m), during stratified water column conditions and spring tides. Algal tissue nitrogen and growth weight (before and after each deployment), water-column temperature (continuous), and inorganic water-column nutrient concentrations (taken on 3 days during the experiment) were measured. Abrupt drops in temperature (up to 3 °C in an hour) occurred twice daily, at 10 m and occasionally at 5 m depth, associated with the internal tide. Date and deployment depth had significant effects on U. lactuca tissue nitrogen, showing a significant increase for deeper deployments and a positive correlation with the duration of cool water (< 15.8 °C, > 1 μM NO 3 −) at the deployment depth. On days when temperature remained above 15.8 °C at all depths (15.8 °C was established as the temperature below which nitrate was above 1 μM), no significant increase in tissue nitrogen was detected at any depth. Growth and tissue nitrogen were significantly and inversely correlated for mid-water (5 m) and bottom (10 m) deployments, but not at the surface. The data support the hypothesis that U. lactuca can increase tissue nitrogen in response to the cold phase of the semidiurnal internal tide.

Studies on the constituents of the green alga Ulva lactuca

Phytochemical investigations on a marine green alga Ulva lactuca led to the isolation of two new compounds (E)-6-heptacosen-5-one (1) and (E)-6-octadecen-5-ol (2), along with four known compounds, (Z)-10-hexacosene (3), docosanoic acid (4), palmitic acid (5), and isofucosterol (6). Compounds 3 and 4 were isolated for the first time from this species. The structures of the compounds were deduced with the help of modern spectroscopic techniques.

Temporal variation in egg-capsule deposition by Nassarius vibex (Gastropoda: Nassariidae)

The morphology and the deposition periods of egg capsules by the bruised nassa Nassarius vibex were investigated on two beaches located on the southeast coast of Brazil. The nassariids were associated with the charru mussel Mytella charruana, which forms beds on soft mud-bottoms. A total of 1558 capsules were collected, only from the fronds of the green alga Ulva lactuca, 859 for Camaroeiro Beach and 699 for Cidade Beach. The mean sizes of the egg capsules and numbers of eggs or larvae per capsule were similar on the two beaches, as were the periods of capsule deposition. At Camaroeiro Beach, capsules first appeared in May 2006, reached a peak in August 2006, and disappeared in December 2006. At Cidade Beach, the first capsules were recorded in July 2006, with a peak in August 2006. A second peak was also observed at this beach between January 2007 and April 2007. The two periods of deposition recorded at the latter beach may indicate two periods of recruitment in the same year for N. vibex. Regarding the influence of intertidal level on capsule deposition, there was a significant difference in the number of capsules between the levels at Camaroeiro Beach (F = 7.445, p < 0.05), and for the second capsule-deposition peak at Cidade Beach (F = 6.382, p < 0.05). This study revealed a selective pattern of capsule deposition, with individuals of N. vibex using only fronds of U. lactuca. This process was influenced by the morphodynamics of the two beaches, with the nassariids maximizing the survival of embryos by depositing more capsules and more eggs per capsule in better-protected parts of the mytilid beds.

Improvement of lipid profile and antioxidant of hypercholesterolemic albino rats by polysaccharides extracted from the green alga Ulva lactuca Linnaeus

Sulfated polysaccharides from Ulva lactuca were extracted in hot water and precipitated by ethanol then orally gavaged to rats fed on a hypercholesterolemic diet for 21 days to evaluate the antihypercholesterolemic and antioxidant actions. Atorvastatine Ca (Lipitor) was used as a reference drug. The intragastric administration of U. lactuca extract to hypercholesterolemic rats caused significant decrease of serum total lipids, triglycerides, total cholesterol, LDL-cholesterol and vLDL-cholesterol levels. Whereas, HDL-cholesterol concentration was markedly increased by 180%. Aqueous extract showed a significant ameliorative action on elevated atherogenic index, creatine kinase and lactate dehydrogenase activities of hypercholesterolemic group. Furthermore, serum activities of transaminases and alkaline phosphatase were also improved. High fat diet intake caused a highly significantly elevated serum urea, creatinine concentration. These effects were reversed by oral administration of U. lactuca extract. Sulfates polysaccharides extract of U. lactuca ameliorate hepatic enzymatic (catalase, glutathione peroxidase and superoxide dismutase), non-enzymatic (reduced glutathione & total thiol) antioxidant defenses and thiobarbituric acid reactive substances. In conclusion, the tested U. lactuca polysaccharides extract has potent hypocholesterolemic and antioxidant effects in experimentally-induced hypercholesterolemic animal model.

Antidiatom and antibacterial activity of epiphytic bacteria isolated from Ulva lactuca in tropical waters

Bacteria and diatoms are primary colonizers of marine surfaces and hence play a crucial role in the attachment and subsequent growth of macroorganisms. It has been suggested that the temperate green alga Ulvalactuca relies on the defence provided by the epiphytic bacterial community to regulate surface fouling of colonising organisms. In this study, ten resident bacterial isolates from tropical U. lactuca were tested for their antibacterial and antidiatom properties that may regulate surface colonization on the algae. Sixty percent of the epiphytic isolates expressed antibacterial properties against other resident bacteria and 80% had antidiatom activity against the pennate diatom, Cylindrothecafusiformis. Isolates of the Pseudoalteromonas genus showed both- antibacterial and antidiatom activities, while members of the genus Bacillus, Vibrio and Shewanella mostly possessed antidiatom activity. Our results show that a high proportion of bacterial isolates from tropical U. lactuca, like that of their temperate counterparts contain antibiotic properties that might impact on the bacterial community composition and prevent fouling by diatoms.

Eelgrass recovery after nutrient enrichment reversal

Mumford Cove, a 48 ha Connecticut embayment on Long Island Sound, has a history of excessive nutrient inputs and corresponding eutrophic conditions with concomitant eelgrass ( Zostera marina L.) loss. From 1945 to 1987, a municipal wastewater treatment facility discharged into the cove. In 1987, when the wastewater outfall was diverted to another location, the cove supported a near monoculture of the green algae Ulva lactuca L., covering 74% of the bottom. By 1988, macroalgal areal cover in Mumford Cove had declined to 9%. When we first sampled the cove in 1992, Z. marina and Ruppia maritima L. were present. By 1999, areal distribution of Z. marina and R. maritima had expanded to cover a third of the bottom. Periodic summertime surveys from 2002 through 2004 indicated that Z. marina was present in approximately half of the cove; R. maritima was sparse. Fifteen years after termination of nutrient enrichment, this cove had recovered from 40 years of point source anthropogenic nutrient input, returning from an Ulva-dominated to a Zostera-dominated state.

Comparing macroalgal food and habitat choice in sympatric, tube-building amphipods, Ampithoe lacertosa and Peramphithoe humeralis

For small tube-building amphipods that live on the algae they consume, food and habitat are tightly linked. This study compared two closely related amphipods to determine whether the species’ algal preferences are based on the food value of the algae or on some other aspect of their algal habitat. Ampithoe lacertosa and Peramphithoe humeralis are both abundant on Shannon Point beach (Anacortes, Washington, USA; 48°30.542′ N, 122°41.070′ W) but specialize on different algae. In observations and laboratory experiments conducted July–September 1997, 2007, and 2008, the two species exhibited markedly different choices of food and habitat when offered six common macroalgae. Ampithoelacertosa ate all algae offered, but preferentially built tubes on the green alga Ulvalactuca. Survival was relatively low among juveniles maintained on single species diets, except when they were fed Mazzaella splendens. Conversely, P.humeralis consumed primarily the brown kelp Saccharina latissima, Alariamarginata, and Desmarestialigulata and preferred those species for tube building. Juvenile P.humeralis could not survive on a diet of U.lactuca or M. splendens. While A.lacertosa builds simple, temporary tubes and relocates frequently, P.humeralis is a highly thigmotactic species that builds long-term, complex tubes on the alga it prefers to eat. Feeding and habitat preferences of the two species were not clearly linked to nitrogen content of the algae, C:N ratio, or toughness of the algal tissue. Instead, preferences of the species may be related to their mobility and the permanence of the tubes they build. Ampithoelacertosa and P.humeralis also use different feeding strategies; the former appears to mix algae to produce a high-quality diet, while the latter is more selective and has a capacity for compensatory feeding. The species are abundant on the same protected rocky shores, but specialize on different algae for habitat and food. Results suggest that the nutritional requirements of these sympatric mesograzers differ considerably and even closely related species can exhibit divergent behavioral strategies.

Differential responses to cadmium induced oxidative stress in marine macroalga Ulva lactuca (Ulvales, Chlorophyta)

This study describes various biochemical processes involved in the mitigation of cadmium toxicity in green alga Ulva lactuca. The plants when exposed to 0.4 mM CdCl(2) for 4 days showed twofold increase in lipoperoxides and H(2)O(2) content that collectively decreased the growth and photosynthetic pigments by almost 30% over the control. The activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione peroxidase (GPX) enhanced by twofold to threefold and that of catalase (CAT) diminished. Further, the isoforms of these enzymes, namely, Mn-SOD (approximately 85 kDa), GR (approximately 180 kDa) and GPX (approximately 50 kDa) responded specifically to Cd(2+) exposure. Moreover, the contents of reduced glutathione (3.01 fold) and ascorbate (1.85 fold) also increased substantially. Lipoxygenase (LOX) activity increased by two fold coupled with the induction of two new isoforms upon Cd(2+) exposure. Among the polyunsaturated fatty acids, although n - 3 PUFAs and n - 6 PUFAs (18:3n - 6 and C18:2n - 6) showed relatively higher contents than control, the latter ones showed threefold increase indicating their prominence in controlling the cadmium stress. Both free and bound soluble putrescine increased noticeably without any change in spermidine. In contrast, spermine content reduced to half over control. Among the macronutrients analysed in exposed thalli, the decreased K content was accompanied by higher Na and Mn with no appreciable change in Ca, Mg, Fe and Zn. Induction of antioxidant enzymes and LOX isoforms together with storage of putrescine and n - 6 PUFAs in cadmium exposed thallus in the present study reveal their potential role in Cd(2+) induced oxidative stress in U. lactuca.

The effects of ethanolic extract of green algae (ulva lactuca l.) on blood cholesterol levels in male rats induced by a high fat diet

Background : Nowadays, cardiovascular disease is increasing in number each year. It is triggered by high cholesterol diet consumed by urban people. Green algae (Ulva lactuca L.) contains phytomelatonin levels that can ease cholesterol. Objective : To know about the effect of giving green algae ethanolic extract in male strain Wistar mice's cholesterol level. Methods : This research involved 36 male strain Wistar mice divided to six groups. Negative control injected with 2 ml/200 gBW lard, positive control injected with 0,18 mg/200 gBW simvastatin and lard, group III, V, V each given lard and injected with ethanolic extract of green algae at a dose of 50 mg/kgBW, 100 mg/kgBW and 200 mg/kgBW respectively, and normal control given AD 2 dietary treatment. Each group was given the same treatment peroral in 56 days and the blood was taken every 14 days through sinus orbitalis. The blood cholesterol level was analyzed by using enzymatic CHOD-PAP method. Data obtained were statistically examined using Two way ANOVA , Kolmogorov Smirnov, Levene's method and LSD with confidence level at 95%. Results : The blood cholesterol level were not significanly different between the negative and normal control. The result of cholesterol level for 14, 28, and 42 days for all group did not increase compared to negative control, but cholesterol level in group with 200 mg/kgBW dose extract indicated significant difference with negative control for 56 day. Conclusion : Giving ethanolic extract of green algae for 56 days decreased blood cholesterol level in male rats.

Assessment of heavy metals (Cd, Cr and Pb) in water, sediment and seaweed (Ulva lactuca) in the Pulicat Lake, South East India

The concentrations of three heavy metals chromium (Cr), cadmium (Cd) and lead (Pb) were examined in water, sediment and green algae (Ulva lactuca); collected from six different stations at Pulicat Lake, which receives effluents from industries located in North Chennai Coastal region. Concentrations of Cd (64.21μgg−1) and Cr (28.51μgg−1) were found to be high in sediment, whereas in green algae concentration of Pb (8.32μgg−1) was higher than water and sediment samples. The relative abundance of these heavy metals in U. lactuca and sediment were found to be in the order Cd>Cr>Pb, whereas in water the ratio was found to be Cr>Pb>Cd. The seasonal variations in Cd and Pb followed a similar pattern in both seaweeds and sediments, but not in water samples. Spearman correlation coefficient study showed no significant correlation in the concentration of metals in U. lactuca, water and sediment samples.

Research note: Irradiance of photosynthetically active radiation determines ultraviolet‐susceptibility of photosynthesis in Ulva lactuca L.(Chlorophyta)

SUMMARYThe respective ratio of photosynthetically active to ultraviolet radiation is of crucial importance to results obtained in ultraviolet (UV)‐research on photoautotrophic organisms. Specimens of the green macroalga Ulva lactuca L. were exposed to a constant irradiance of UV‐radiation at increasing irradiances of photosynthetically active radiation (PAR). The effects of experimental irradiance and spectral composition on photoinhibition of photosynthesis and its recovery were monitored by chlorophyll fluorescence measurements and the activity of the xanthophyll cycle was assessed by high performance liquid chromatography‐(HPLC) based pigment analysis. Results indicate a UV‐induced delay in recovery from PAR‐induced photoinhibition and a deceleration of violaxanthin conversion within the xanthophyll cycle due to the presence of UV‐radiation. Also the concentration of the protective pigment lutein increased considerably and could be indicative of the existence of an additional light‐protective mechanism, as, for example, the lutein‐epoxid cycle in Ulva. In total, results clearly show that the extent of UV‐induced inhibition of photosynthesis to be found in UV‐exposure experiments is highly dependent on the irradiance of background photosynthetically active radiation: with increasing irradiance of PAR the UV‐effects were diminished. Exemplified by the green algae Ulva lactuca this study demonstrates the crucial importance of the ratios of PAR:UV applied in UV‐research, particularly when conducting laboratory experiments in an ecological context.

Biosorption of Pb(II) and Cd(II) from aqueous solution using green alga ( Ulva lactuca) biomass

The biosorption characteristics of Pb(II) and Cd(II) ions from aqueous solution using the green alga ( Ulva lactuca) biomass were investigated as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of the metal ions by U. lactuca biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The monolayer biosorption capacity of U. lactuca biomass for Pb(II) and Cd(II) ions was found to be 34.7 mg/g and 29.2 mg/g, respectively. From the D–R isotherm model, the mean free energy was calculated as 10.4 kJ/mol for Pb(II) biosorption and 9.6 kJ/mol for Cd(II) biosorption, indicating that the biosorption of both metal ions was taken place by chemisorption. The calculated thermodynamic parameters (Δ G°, Δ H° and Δ S°) showed that the biosorption of Pb(II) and Cd(II) ions onto U. lactuca biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of both metal ions followed well pseudo-second-order kinetics.

Norisoprenoids from Ulva lactuca

Five norisoprenoids were isolated from the green marine alga Ulva lactuca. Two new compounds were assigned to (3R,5R,6R,7E)3,5,6-trihydroxy-7-megastigmen-9-one (1) and (3S,5R,6S,7E)3,5,6-trihydroxy-7-megastigmen-9-one (2). The structures and absolute configurations of the five compounds were determined by analyses of NMR, MS and circular dichroism (CD).

Removal of toxic chromium from wastewater using green alga Ulva lactuca and its activated carbon

Biosorption of heavy metals can be an effective process for the removal of toxic chromium ions from wastewater. In this study, the batch removal of toxic hexavalent chromium ions from aqueous solution, saline water and wastewater using marine dried green alga Ulva lactuca was investigated. Activated carbon prepared from U. lactuca by acid decomposition was also used for the removal of chromium from aqueous solution, saline water and wastewater. The chromium uptake was dependent on the initial pH and the initial chromium concentration, with pH ∼1.0, being the optimum pH value. Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were fitted well the equilibrium data for both sorbents. The maximum efficiencies of chromium removal were 92 and 98% for U. lactuca and its activated carbon, respectively. The maximum adsorption capacity was found to be 10.61 and 112.36 mg g −1 for dried green alga and activated carbon developed from it, respectively. The adsorption capacities of U. lactuca and its activated carbon were independent on the type of solution containing toxic chromium and the efficiency of removal was not affected by the replacing of aqueous solution by saline water or wastewater containing the same chromium concentration. Two hours were necessary to reach the sorption equilibrium. The chromium uptake by U. lactuca and its activated carbon form were best described by pseudo second-order rate model. This study verifies the possibility of using inactivated marine green alga U. lactuca and its activated carbon as valuable material for the removal of chromium from aqueous solutions, saline water or wastewater.

Biosorption of Direct Yellow 12 from aqueous solution using green alga Ulva lactuca

The potential of commonly available green alga Ulva lactuca was investigated as viable biomaterials for removal of synthetic azo dye (Direct Yellow 12, DY-12) from aqueous solution. The results obtained from the batch experiments revealed that the ability of the U. lactuca to remove DY-12 from its aqueous solution was dependent on the dye concentration, pH, and algal biomass but less dependent on the particle size of the U. lactuca. The equilibrium conditions and kinetics of adsorption were investigated, and the adsorption kinetic was consistent with the pseudo-second-order model (R 2=1). The adsorption isotherm followed only the Freundlich model with a correlation coefficient R 2=0.99. This study demonstrated that the U. lactuca could be used as an effective biosorbent for the removal of DY-12 from its aqueous solution.