Enteromorpha Research Articles

Determination of the Optical Band gap Energy from the Extraction and Evaporation of Anthocyanin Compound Sea Lettuce (Ulva Lactuca L.) Using Tauc Plot Method

The optical energy gap of anthocyanin compounds from sea lettuce extract (Ulva lactuca L.) has been calculated using the Tauc plot method. Sea lettuce plants taken at Sanur Beach Bali. The sea lettuce was dried then mashed and extracted for 24 hours, the last being macerated through three cycles. The extraction results are then evaporated to obtain a thick extract solution. Extracted and evaporated-extraction samples were characterized by UV-Vis in the wavelength range of 200-800 nm. From the characterization results, it was found that the absorption of anthocyanin compounds for the extracted samples was at a wavelength of 268 and 412 nm. Meanwhile, for the extraction-evaporation sample, the absorption is at a wavelength of 286.5 and 408 nm. By using the Tauc plot method, the optical energy gap values ??for the extracted and extraction-evaporated samples were 2.69 and 2.54 eV, respectively. Therefore, anthocyanin compounds from both extracted and evaporation-extracted samples qualify as dye sensitized solar cells (DSSC) for TiO2 semiconductors.

Phytochemical Constituents and Antimicrobial Activity of Marine Green Seaweed Ulva lactuca

The aim of this study is to determine the presence of Ulva seaweeds, possibly by analyzing the quality of seaweed powder extracts and some organic solvents. It belongs to the order Ulvaales. Ulva lactuca is a widespread macro algae growing the Mediterranean coast phylum Chlorophyta, commonly known as “sea lettuce”. Collected from the Gulf of Mannar Tamil Nadu, India. Dry the Ulva seaweeds and grind it in a food processor until it becomes a fine powder. The powder is dried in an oven at 600c for 24 hours. Alkaloids, Flavonoids, Saponins and Tannins. dried seaweed nutrients rich in energy 252.72kcal/mg/gm, carbohydrates 49.63mg/gm, less protein 12.21mg/gm, fat 1.04mg/gm less than gm, high crude fiber, ash15.8mg/g, high moisture 21.74mg/g. in the UV –visible spectrum of seaweed extract TLC analysis 200-800nm found a high value of0.925, to0.477, GC-MS RF value of8.014, and FTIR analysis of seaweeds Ulva found a high value of 618 to 3525cm-1 and HPLC showed retention time 2.213- 3.730. The antimicrobial studies maximum inhibition zone, minimum concentrations, minimum inhibition zone and maximum activity of Klebsiella pneumoniae, are methanol extract 10mm, Staphylococcus aureus, ethyl acetate extract11mm, Candida albicans 10.5mm were respectively.

Genetic diversity of Ulva lactuca from the intertidal zone in Ulee Lheue beach Aceh, Indonesia

Ulee Lheue Beach in Banda Aceh was developed for tourism. The macroalgae and seaweed species found in this area have been widespread but never exploited. Among these species is the green seaweed, Ulva lactuca, commonly known as sea lettuce. The physiological variations and genetic features of the seaweed can be attributed to the variations in the coastal environment. This study aims to describe the molecular identity of the genetic diversity of U. lactuca from the intertidal zone at Ulee Lheue Beach. The development of molecular biotechnology has enabled identification the gene expression through genomic DNA to PCR amplification. Genetic distance was determined using UPGMA. The results from 600-bp fragments were analyze the genetic diversity. A total of 15 (31%) expression identified as polymorphic (0.500). Heterozygosity (He) and allelic differential (Na) diversity were found of 1.500–3.000. The highest PIC was observed in the rbcL1, with a correlation between subpopulations of 0.459. PCR amplification using the degenerate primer rbcL1 produced fragments ranging from 300 to 460 bp, whereas the expression of UL2 was detected at 448 and 500 bp using the rbcL2 primer. The phylogenetic identify are shown two (2) clusters. The populations of UL1, UL3, and UL4 were found a close relationship. Furthermore, the UL1 and UL2 populations were further divided into distinct clusters but related to the main branch of UL3. Based on this research, the concern of U. lactuca species for industrial and biotechnology destinations, we can describe a suitable method for obtaining he genetic distances between species.

The cultivated sea lettuce (Ulva) microbiome: Successional and seasonal dynamics

The seaweed production industry is rapidly expanding worldwide. The green seaweed Ulva is increasingly recognized as an excellent sustainable feedstock, due to its high growth rates, its wide tolerance to environmental conditions, and its potential in bioremediation and integrated multi-trophic aquaculture. Seaweed associated microbes could play an important role in the optimization of the Ulva-crop-system, by increasing host growth, changing biochemical composition, and fending off pathogens that cause disease. In order to be successfully implemented, however, microbiota manipulation requires fundamental knowledge on the successional dynamics of the cultivated Ulva microbiome. In this study, we monitored the dynamics of Ulva-associated bacterial communities over a time-period of eleven months, from the nursery phase and outplanting in the field up to the harvest. We compared microbial dynamics in land-based tanks and an offshore seafarm, as well as natural populations of Ulva fenestrata and Ulva linza. Our results showed that Ulva hatchlings in the nursery phase harboured a distinct microbiome compared to outplanted Ulva. The hatchling communities were dominated by 1–3 genera, several of which have been identified as growth-promoting bacteria before (e.g., Sulfitobacter, Algitalea). In addition, we found that the nursery conditions played a larger role in the microbiome composition than host specificity, suggesting that the nursery environment is a crucial microbial source pool. The bacterial composition underwent a swift transformation following outplanting, differing significantly from the nursery samples within only seven days. Our results demonstrated that the bacterial communities in the nursery phase remain susceptible to newly introduced microbiota. Controlled nursery conditions could therefore provide the ideal opportunity for microbiota manipulation, but the acquired microbes might not endure the transition to open-water conditions.

Chironomidae collected at the seashore in Kume Island, Japan

Local residents and tourists of Kume Island suffer from the biting of Leptoconops taiwanensis (Lien, Lin & Weng 1998) (Ceratopogonidae), a species known as asa-mushi (sea lettuce bug). Because L. taiwanensis bites tend to occur while harvesting sea lettuce, some locals mistakenly believe that L. taiwanensis inhabits the sea lettuce. The objectives of the current study are to (i) identify the chironomid species inhabiting the sea lettuce, (ii) determine the distribution of the larvae, and (iii) perform a faunistic investigation of Chironomidae at Shinri Beach. Only one male chironomid species, Ainuyusurika tuberculatum (Tokunaga, 1940), emerged from the samples taken from the beach. The density of chironomid larvae was the highest in the presence of sea lettuce. A total of 53 males were collected using light traps, of which we identified males of seven genera and seven species belonging to three subfamilies. No L. taiwanensis were collected in this study.

A comprehensive study on ecological insights of Ulva lactuca seaweed bloom in a lagoon along the southeast coast of India

Ulva lactuca, commonly known as sea lettuce is a green macroalgae (chlorophyta) and its uncontrolled proliferation forms a bloom, which causes ecological imbalances and adversely impacts brackishwater ecosystems. Algal bloom can harm the environment and aquatic organisms, but it can also be beneficial if harvested and utilized for industrial purposes. A massive bloom of green macroalgae was observed in the Muttukadu lagoon, located along the southeast coast of India in the Bay of Bengal. A comprehensive study was taken up to assess the spatial distribution, proximate, nutrients, minerals, heavy metals, and factors inducing the bloom. For this study, high-resolution satellite images (Sentinel 2) were used. The spatial distribution of seaweed was mapped using Floating Algae Index (FAI), Modified Floating Algae Index (MFAI), Normalized Difference Red Edge (NDRE) Index and Seaweed Index (SI) models. Results were validated using the MAVIC 3 pro drone and field survey. The SI model was found to be more accurate compared to other models. The bloom exhibited notable temporal dynamics, with peak coverage observed in the last week of May 2023 with a spread area of about 100.05 ha, the bloom intensity was found to be high till the last week of June 2023, after which it gradually declined. The proximate composition (%) of Ulva lactuca showed the moisture content is about 80.00 ± 2.98, crude protein 24.17 ± 1.80, crude lipid 0.81 ± 0.05, Total Ash 37.45 ± 1.44, Fiber (8.92 ± 0.41), and Acid Insoluble Ash (16.18 ± 1.16). The mineral concentration was in the order Ca > Na > Mg > K > P. Iron (Fe) was observed to be high compared to other micronutrients, with a concentration of 1164.40 mg/kg. Rich nutrients and low heavy metal concentration significantly can boost the selling cost of Ulva lactuca providing livelihood support for the coastal fisherfolk.

Sea lettuce (Ulva ohnoi) cultivation in biofloc technology: growth performance and characterization of bioactive compounds

This work evaluated the biofloc technology cultivation of Ulva ohnoi on its growth performance and biocompounds contents. Ulva ohnoi was cultivated under an initial density of 6 g·L-1 for 28 days using water from a biofloc tank which was exchanged daily at a 90% rate. Temperature, salinity, and illuminance were measured daily. Algae growth and their density was adjusted weekly. Results showed an average plant growth of 1.15%·day-1 (49.5 g·week-1). A significant difference was observed when comparing the initial (2.64 ± 0.3%) and final (4.62 ± 0.2%) ulvan concentration, in addition to a protein increase of 30.2%. No statistical differences were found for concentrations of phenolics and chlorophylls. An increase in flavonoids was observed on days 7 and 14 (0.41 ± 0.04; and 0.41 ± 0.07 μg·g-1 of dry weight), as well as a decrease in carotenoids (41.3%). In conclusion, increases in protein and ulvan were observed after Ulva ohnoi was cultivated in bioflocs

Short term decreases in salinity, combined with the right choice of species, can allow for a more nutritious sea lettuce lipid profile

The sea lettuce Ulva spp is becoming an increasingly important macroalgae for aquaculture. Sea lettuce can be grown on- and off-shore, displays high growth rates, and its biomass possesses attractive nutritional benefits. Among those are their fatty acids (FA) and lipid profiles, rich in omega 3 Polyunsaturated Fatty Acids (PUFAs) as well as bioactive lipids. In order to tailor those properties for food applications, we explored the use of a short-term (seven days) low salinity treatment to modulate the lipid profile of two species of Ulva. We found large quantitative differences between species, and while a low-salinity treatment negatively affected growth, Ulva australis’ lipid profile was positively impacted. Total FA particularly ɷ-3 PUFAs, increased three-fold, as well as most polar lipid species including known bioactive compounds. This study highlights profound differences between species and describes a simple method to increase the nutritional properties of Ulva biomass for food applications.

Discovery and Anti-Inflammatory Activity of a Cyanobacterial Fatty Acid Targeting the Keap1/Nrf2 Pathway.

The monounsaturated fatty acid 7(E)-9-keto-hexadec-7-enoic acid (1) and three structurally related analogues with different oxidation states and degrees of unsaturation (2-4) were discovered from a marine benthic cyanobacterial mat collected from Delta Shoal, Florida Keys. Their structures were elucidated using NMR spectroscopy and mass spectrometry. The structure of 1 contained an α,β-unsaturated carbonyl system, a key motif required for the activation of the Keap1/Nrf2-ARE pathway that is involved in the activation of antioxidant and phase II detoxification enzymes. Compounds 1-4 were screened in ARE-luciferase reporter gene assay using stably transfected HEK293 cells, and only 1 significantly induced Nrf2 activity at 32 and 10 µM, whereas 2-4 were inactive. As there is crosstalk between inflammation and oxidative stress, subsequent biological studies were focused on 1 to investigate its anti-inflammatory potential. Compound 1 induced Nqo1, a well-known target gene of Nrf2, and suppressed iNos transcript levels, which translated into reduced levels of nitric oxide in LPS-activated mouse macrophage RAW264.7 cells, a more relevant model for inflammation. RNA sequencing was performed to capture the effects of 1 on a global level and identified additional canonical pathways and upstream regulators involved in inflammation and immune response, particularly those related to multiple sclerosis. A targeted survey of marine cyanobacterial samples from other geographic locations, including Guam, suggested the widespread occurrence of 1. Furthermore, the previous isolation of 1 from marine diatoms and green algae implied a potentially important ecological role across marine algal eukaryotes and prokaryotes. The previous isolation from sea lettuce raises the possibility of dietary intervention to attenuate inflammation and related disease progression.

Life cycle assessment of carbon-based adsorbent preparation from algal biomass

The adsorbent prepared by algae was found to be very feasible and effective for removing tetracycline from water. Therefore, this manuscript investigated the capacity of adsorbents through co-pyrolysis of Enteromorpha (EN) and Chlorella vulgaris (CV). Through the experiment, it was determined that the pyrolysis of Enteromorpha and Chlorella vulgaris was carried out at 500 °C at the mixing ratio of 2∶8. The obtained biochar was mixed with NaOH at 1∶0.5 and activated at 800 °C. The mixed algae-based adsorbent had the highest removal rate of tetracycline (97.56%). To further evaluates the environmental impact of the adsorbent preparation process, OpenLCA was applied to the three adsorbent preparation processes using Enteromorpha (EN), Chlorella vulgaris (CV) and mixed algae (MIX). The results show that EN-based adsorbent preparation has the least environmental impact. This is because CV requires much freshwater during cultivation, while EN is cultured in ocean. The culture of CV-based and MIX-based adsorbents account for the majority of all environmental impact indicators. For example, the CO2 emissions of CV and MIX culture account for 75.05% and 69.21% in preparation process, respectively. The sensitivity analysis showed that the environmental impact indicators of CV-based and MIX-based adsorbents preparation was extremely sensitive to aquaculture water. If 80% of the aquaculture water is replaced with aquaculture wastewater, the environmental impact of the MIX-based adsorbent preparation will be the least of the three schemes. The LCA of algae-based adsorbent preparation was carried out in this study, which provided guidance for the optimization of adsorbent preparation engineering.

The Correlation between Dye absorption Wavelength and Illumination Wavelength on DSSC Performance

This study examines the effect of the wavelength of light illuminated on DSSC on the absorption wavelength and gap dye energy. The dye used was sea lettuce anthocyanin from Sanur Beach, Bali. As much as 20 grams of dried sea lettuce powder was dissolved in 80 mL of 96% ethanol and 6% HCl. After 24 hours of immersion, it was filtered with Whatman 41 paper. The filtrate was characterized using a UV-Vis-NIR spectrophotometer so that the absorption wavelengths of the anthocyanin dye were 272.5 nm, 417 nm, and 653.5 nm. The gap energy was calculated using the Tauc Plot method, and the result was 2.826 eV. The dye was applied to make DSSC using the sandwich method, which was then irradiated with white, red, and purple LEDs with respective wavelengths of 400–700 nm (with peaks at 439.67 nm and 550.29 nm), 629.04 nm and 425.38 nm and variations in intensity values, namely 1000 lux, 2000 lux, and 3000 lux. Illumination using purple LEDs produces the maximum current and highest efficiency compared to white and red, namely 1.33 mA, 1.57 mA, and 1.83 mA for 1000 lux, 2000 lux, and 3000 lux, respectively, and the efficiency is 0.0039 for 1000 lux. The purple color has a wavelength close to and intersects with the absorbance wavelength of the dye and has energy (2.918 eV) greater than the gap energy of the sea lettuce dye.

Macro- and micro-algae-based carbon composite for pharmaceutical wastewater treatment: Batch adsorption and mechanism study

Biochar synthesized from algal biomasses acts as an efficient adsorbent to remove tetracycline (TC) from aqueous solutions. In this study, a mixture of Enteromorpha (EN) and Chlorella vulgaris (CV) was pyrolyzed at 500 °C, then activated with NaOH at 800 °C to prepare composite biochar (ECA-B). The effects of TC concentration (50–500 mg·L−1), pH (3–11), temperature (30 °C–50 °C), and contact time (0–960 min) on TC absorption were investigated. Results revealed that in aqueous solutions, the biochar (EC4:1-0.5)prepared with CV and EN at the mass ratio of 4:1 and the impregnation ratio of 0.5 had the optimal TC adsorption capacity (Qm = 376.878 mg·g−1). The removal rate of EC4:1-0.5 remained above 80 % after five cycles. The surface area of EC4:1-0.5 (583.329 m2·g−1) increased by three and four times that of EN and CV, respectively. Intraparticle diffusion was considered as the major limitation for the adsorption of TC onto EC4:1-0.5. This investigation provides a method for the synthesis and optimization of algal biomass-based activated carbon for the absorption of organic pollutants in wastewater.

Ulva: An emerging green seaweed model for systems biology.

Green seaweeds exhibit a wide range of morphologies and occupy various ecological niches, spanning from freshwater to marine and terrestrial habitats. These organisms, which predominantly belong to the class Ulvophyceae, showcase a remarkable instance of parallel evolution toward complex multicellularity and macroscopic thalli in the Viridiplantae lineage. Within the green seaweeds, several Ulva species ("sea lettuce") are model organisms for studying carbon assimilation, interactions with bacteria, life cycle progression, and morphogenesis. Ulva species are also notorious for their fast growth and capacity to dominate nutrient-rich, anthropogenically disturbed coastal ecosystems during "green tide" blooms. From an economic perspective, Ulva has garnered increasing attention as a promising feedstock for the production of food, feed, and biobased products, also as a means of removing excess nutrients from the environment. We propose that Ulva is poised to further develop as a model in green seaweed research. In this perspective, we focus explicitly on Ulva mutabilis/compressa as a model species and highlight the molecular data and tools that are currently available or in development. We discuss several areas that will benefit from future research or where exciting new developments have been reported in other Ulva species.

Chocolates enriched with seaweed: Sensory profiling and consumer segmentation

The idea of using macroalgae as a sustainable functional food is not new, however studies in the context of phycogastronomy are scarce. The aim of the current study was to develop three different types of chocolate enriched with marine macroalgae (seaweeds) and, through binary logistic regression models, outline their sensory profile (104–139 volunteers per sample), identify the profile of possible buyers and the sensory drivers of liking. The sensory characterization performed for each sample highlighted several attributes imparted by the added seaweeds, as the salty taste derived from kombu and the astringent stimuli and dehydrated fruits flavour note derived from nori. Moreover, together with the marine/ocean smell and vegetable flavour notes, results show there is a direct link between dried Portuguese sea lettuce and a distinctive green tea/matcha flavour. Significant differences were found among the purchase intent, flavour, and overall liking scores for each sample: milk chocolate with kombu and ruby chocolate with nori achieved a higher degree of acceptability by Portuguese consumers than white chocolate with sea lettuce. Along with the sensory drivers of liking uncovered, the preformed a priori and a posteriori consumer segmentation provided useful information for a better understanding of the associations between sensory perception, hedonic appraisal, chocolate consuming patterns and purchase intent of these innovative products. Results show that some macroalgae have the potential to be used in sweet formulations (chocolate) and this appears to be a good strategy to introduce macroalgae into Portuguese markets.

Structural Development of Marine Green Alga (Ulva rigida C. Agardh, 1823) during Cultivation

Ulva rigida C. Agardh (sea lettuce) is a marine green alga. It grows naturally near shorelines in areas with freshwater influence. It can also be cultivated easily on farms and can be developed into many healthy food products, which bring in revenue for Thailand. It is important to develop an effective way to cultivate the alga. In this research, the molecular biology of sea lettuce using the tufA gene for the identification of Ulva genus and morphological characters at different culturing periods of U. rigida thallus were investigated using a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results revealed that the U. rigida alga consisted of various cell shapes including elliptic, irregular triangle, irregular quadrilateral, pentagonal and polygonal. The cell size increased with increasing periods of culture. However, when the alga was cultured for 28 days, the cell sizes were smaller than the original cells due to cell division during aging, resulting in an increase in cell numbers. U. rigida had grown rapidly in 14 days which was a relatively short period of cultivation. The results of this study indicate that U. rigida has a potential to be scaled up in pilot and commercial scales. HIGHLIGHTS The molecular analysis of sea lettuce from Phetchaburi Coastal Aquaculture Research and Development Center, Sub District: Bang Kaeo, District: Ban Laem at Phetchaburi Province, Thailand was found to be rigida The morphological and anatomical characters of rigida thalli were studied with light microscope, transmission electron microscope and scanning electron microscope techniques The cell sizes of rigida thalli changed with culturing days. They were the largest at 14 days in the surface view, and at 14 and 21 days in the transverse section GRAPHICAL ABSTRACT

Influence of Total Suspended Solids on the Growth of the Sea Lettuce Ulva lactuca Integrated with the Pacific White Shrimp Litopenaeus vannamei in a Biofloc System

A biofloc system is rich in nutrients, which favors the cultivation of macroalgae, but the influence of the system on the performance of macroalgae is unknown. The objective of this study was to analyze the feasibility of introducing the macroalgae Ulva lactuca into the culture of Litopenaeus vannamei in a biofloc system. The first experiment evaluated the influence of 400 mg L−1 and 30 mg L−1 solids concentration of the system in biofloc and von Stosch culture medium on macroalgae growth. In the second experiment, the densities of 1, 2, and 3 g L−1 of U. lactuca were cultivated in an integrated system with shrimp and monoculture treatment. Both experiments had 35 days of cultivation. There was no significant difference in macroalgae growth between the treatments with biofloc and von Stosch culture medium. In the integrated culture, the density of 1 g L−1 showed better nutrient absorption. Shrimp performance was not affected by macroalgae cultivation. In conclusion, the solids did not affect the growth of the macroalgae, and it could be cultivated in a biofloc system for nitrate uptake in integrated culture with shrimp.

Assessment of Bioaccumulation of Heavy Metals and Their Ecological Risk in Sea Lettuce (Ulva spp.) along the Coast Alexandria, Egypt: Implications for Sustainable Management

The pollution of aquatic ecosystems is an issue facing many countries all over the world and may result in issues such as eutrophication in coastal zones. Managing this eutrophication is a real challenge. The current study focuses on the investigation and identification of aquatic environmental characteristics, including the sediments, waters, and seaweed, of seven eutrophicated locations along the Mediterranean coast of Alexandria (Egypt). Different ecological risk assessment and bioaccumulation factors were calculated in order to identify the probable pollution source and the degree of the problem, in addition to the accumulation of heavy metals in the seaweed. The characteristics of the seaweed, sediments, and waters were chemically analyzed and heavy metals were measured. The genetically and biochemically identified seaweed species were Ulva compressa, Ulva fasciata, Ulva lactuca and Ulva linzea. The sediments of the El-Tabia location contained the highest concentrations of Cd, Co, Ni, and Pb, because this location receives these elements from the El-Amia drain. The Abu Qir location was found to contain the highest concentrations of the same heavy metals in the studied water samples because it was located much closer to the Abu Qir harbor. Ecological risk assessment indices indicated moderate to high contamination for most of the studied elements and locations. The results of the bioaccumulation factor analysis indicated that the studied seaweed species are accumulators of trace elements. These seaweed species should be further investigated concerning ecotoxicology if they are to be used in the human diet and for other benefits. This study opens many windows of research to be investigated in the future regarding the sustainable management of polluted coastal zones.

Study on the mechanism of an enteromorpha-based compound inhibitor for inhibiting the spontaneous combustion of coal using in situ infrared spectroscopy and thermal analysis kinetics

To alleviate the environmental pressure caused by enteromorpha (EP) and improve the efficiency of inhibiting spontaneous combustion of coal, attapulgite (ATP) was combined with EP to prepare an enteromorpha-based composite inhibitor (EPH-ATP). The effect of adding different substances on the surface morphology of the synthesized inhibitor was investigated using scanning electron microscopy (SEM). The effects of three inhibitors (enteromorpha hydrogel (EPH), ATP, and EPH-ATP) were analyzed using thermal analysis kinetics and in situ fourier transform infrared spectroscopy (FTIR). The results showed that the addition of ATP had little effect on the apparent morphology and was uniformly distributed in EPH. At heating rates of 5.0, 10.0, 15.0, and 20.0 K/min, it was found that the degree of the completion of spontaneous combustion of coal was directly related to the heating rate, and coal was more likely to react at low heating rates. In addition, during the combustion and decomposition stage, the average activation energy of coal samples treated with EPH-ATP increased by 306%, which greatly improved the reaction difficulty of the spontaneous combustion of coal. According to the changes in the functional groups with temperature, the in situ infrared process was divided into three stages of slow reaction, violent reaction and stable reaction for the first time. Moreover, the mechanism of EPH-ATP reducing the intensity of reaction by scavenging free radicals was clarified. The results show that the enteromorpha-based composite inhibitor has a good inhibitory effect, realizes the sustainable use of EP, and provides a new scientific basis for the prevention and control of the spontaneous combustion of coal.

Effect of Cooking Methods on Nutritional Quality of Sea Lettuce (<I>Ulva lactuca</I>) Flakes

Highlight Research Proximate of Ulva lactuca after cooking treatments were analyzed. The cooking treatments carried out in this study were roasted and boiled-roasted Protein quality such as in-vitro digestibility, protein solubility, and amino acids composition of Ulva lactuca after cooking treatments were analyzed The result showed that boiled-roasted samples had the highest protein content, amino acid score and essential acid index, and predicted-protein efficiency ratio Abstract Plant-based protein has been increasingly demanded as a sustainable protein source. Sea lettuce (Ulva lactuca) is one of the potential sources as plant protein due to its high protein content. During processing, the sea lettuce is exposed to heat which might affect its nutrition, particularly the protein quality. This study aimed to evaluate two different cooking processes on the nutritional quality of the sea lettuce based on the proximate and protein quality analyses. The samples were raw, roasted, and boiled-roasted sea lettuce. All treatment using temperature 100°C. The protein quality was assessed by in-vitro protein digestibility, solubility, and amino acid profiles. The result showed that boiling treatment followed by roasting treatment had significantly higher protein content, amino acid score and essential amino acid index, and predicted-protein efficiency ratio compared with the value of roasting treatment only. It resulted in protein content of 18.87% (dry basis), amino acid score of 37.96%, essential amino acid index of 79.41% and predicted-protein efficiency ratio of 2.58. Therefore, boiling followed with roasting process is recommended to maintain the nutrition quality of sea lettuce.

Highly efficient self-floating jellyfish-like solar steam generators based on the partially carbonized Enteromorpha aerogel.

Solar steam generation (SSG) is a very promising desalination technology. However, new photothermal materials are still to be explored to further reduce the cost, and the device structure is still to be innovated to improve the structural integrality and evaporation performance. In this work, an all-in-one highly-efficient and self-floating jellyfish-like SSG (SFJ-SSG) is developed based on partially carbonized Enteromorpha (EA) aerogel (PCEAA). The carbonized top surface exhibits high solar absorption ability and excellent photothermal effect, while the uncarbonized EA retains the hydrophilicity and high-water transport capability due to the nature of tubular algal plant. Moreover, the heat produced by photothermal effect of the carbonized EA is confined at the top surface due to the thermal insulation of the uncarbonized layer, which is very beneficial for interfacial water evaporation. After optimizing the carbonization time and the height of the SFJ-SSG, a high evaporation rate of 1.87kgm-2h-1 is obtained under 1.0 sun irradiation, which outcompetes most SSG based on carbonized biomass. The development of SFJ-SSG based on EA not only minimizes the cost of SSG, but also solves the EA pollution, ensuring the broad prospect in practical applications.