Red Seaweed Kappaphycus Alvarezii Research Articles

A red seaweed Kappaphycus alvarezii-based biostimulant (AgroGain®) improves the growth of Zea mays and impacts agricultural sustainability by beneficially priming rhizosphere soil microbial community.

The overuse of chemical-based agricultural inputs has led to the degradation of soil with associated adverse effects on soil attributes and microbial population. This scenario leads to poor soil health and is reportedly on the rise globally. Additionally, chemical fertilizers pose serious risks to the ecosystem and human health. In this study, foliar sprays of biostimulant (AgroGain/LBS6) prepared from the cultivated, tropical red seaweed Kappaphycus alvarezii increased the phenotypic growth of Zea mays in terms of greater leaf area, total plant height, and shoot fresh and dry weights. In addition, LBS6 improved the accumulation of chlorophyll a and b, total carotenoids, total soluble sugars, amino acids, flavonoids, and phenolics in the treated plants. LBS6 applications also improved the total bacterial and fungal count in rhizospheric soil. The V3-V4 region of 16S rRNA gene from the soil metagenome was analyzed to study the abundance of bacterial communities which were increased in the rhizosphere of LBS6-treated plants. Treatments were found to enrich beneficial soil bacteria, i.e., Proteobacteria, especially the classes Alphaproteobacteria, Cyanobacteria, Firmicutes, Actinobacteriota, Verrucomicrobiota, Chloroflexi, and Acidobacteriota and several other phyla related to plant growth promotion. A metagenomic study of those soil samples from LBS6-sprayed plants was correlated with functional potential of soil microbiota. Enrichment of metabolisms such as nitrogen, sulfur, phosphorous, plant defense, amino acid, co-factors, and vitamins was observed in soils grown with LBS6-sprayed plants. These results were further confirmed by a significant increase in the activity of soil enzymes such as urease, acid phosphatase, FDAse, dehydrogenase, catalase, and biological index of fertility in the rhizosphere of LBS6-treated corn plant. These findings conclude that the foliar application of LBS6 on Z. mays improves and recruits beneficial microbes and alters soil ecology in a sustainable manner.

Development of Gluten-Free Bread from Brown Rice-Potato Starch Composite Flour Incorporated with Red Seaweed Kappaphycus alvarezii powder

Gluten free diets and lifestyles are rapidly increasing in popularity mainly due to the increase in consumer awareness about gluten related disorders and gluten intolerances. With increasing demand, the food industry strives to develop new food products that are gluten-free and able to be consumed by those who suffer from these conditions. The objective of this study was to develop a gluten-free bread from brown rice-potato starch composite flour incorporated with red seaweed Kappaphycus alvarezii (KA) powder. KA powder, ranging from 2% to 10%, was added, and the physical properties of the gluten- free bread were assessed. Sensory evaluation was conducted using two methods, the descriptive and hedonic tests. The amount of seaweed significantly (p<0.05) influenced the loaf volume, with F5 (10%), the highest concentration of seaweed, having the highest reduction of volume of 15.38% compared to the control F0 (without seaweed). With increasing seaweed concentration, the brightness and yellowness of each bread decreased. The texture profiles of KA-incorporated bread formulations were also affected with the firmness of bread being the most significant change. The descriptive test showed that F5 (10%) had the highest intensity of seaweed effect which affected the colour, texture, aroma, taste and aftertaste of the bread. The hedonic test showed that the most acceptable formulation was F1 (2%). From these formulations, the best formulation F1 (2%) was chosen for further nutrient analysis where it was compared to the control (without seaweed). It was shown that F1 had significantly (p<0.05) higher moisture, ash, fat, and dietary fibre content, but lower carbohydrate and protein content compared to F0 (without seaweed). In conclusion, the formulation of gluten-free KA- incorporated brown rice-potato starch bread had an impact on the bread texture, colour, volume, and nutrient content.

Assessment of regulatory compounds in commercial red seaweed Kappaphycus alvarezii after long-distance transportation

Assessment of regulatory compounds in commercial red seaweed Kappaphycus alvarezii after long-distance transportation

A biostimulant prepared from red seaweed Kappaphycus alvarezii induces flowering and improves the growth of Pisum sativum grown under optimum and nitrogen-limited conditions.

Nitrogen (N) is one of the critical elements required by plants and is therefore one of the important limiting factors for growth and yield. To increase agricultural productivity, farmers are using excessive N fertilizers to the soil, which poses a threat to the ecosystem, as most of the applied nitrogen fertilizer is not taken up by crops, and runoff to aquatic bodies and the environment causes eutrophication, pollution, and greenhouse gas emissions. In this study, we used LBS6, a Kappaphycus alvarezii-based biostimulant as a sustainable alternative to improve the growth of plants under different NO3 - fertigation. A root drench treatment of 1 ml/L LBS6 significantly improved the growth of Pisum sativum plants grown under optimum and deficient N conditions. No significant difference was observed in the growth of LBS6-treated plants grown with excessive N. The application of LBS6 induced flowering under optimum and deficient N conditions. The total nitrogen, nitrate and ammonia contents of tissues were found to be higher in treated plants grown under N deficient conditions. The LBS6 treatments had significantly higher chlorophyll content in those plants grown under N-deficient conditions. The root drench application of LBS6 also regulated photosynthetic efficiency by modulating electron and proton transport-related processes of leaves in the light-adapted state. The rate of linear electron flux, proton conductivity and steady-state proton flux across the thylakoid membrane were found to be higher in LBS6-treated plants. Additionally, LBS6 also reduced nitrogen starvation-induced, reactive oxygen species accumulation by reduction in lipid peroxidation in treated plants. Gene expression analysis showed differential regulation of expression of those genes involved in N uptake, transport, assimilation, and remobilization in LBS6-treated plants. Taken together, LBS6 improved growth of those treated plants under optimum and nitrogen-limited condition by positively modulating their biochemical, molecular, and physiological processes.

Underpinning beneficial maize response to application of minimally processed homogenates of red and brown seaweeds.

Sap from the fresh seaweed Kappaphycus alvarezii (KA) has been reported to improve crop growth, quality, and stress alleviation. However, limited studies are reported for the minimally processed aqueous homogenates (MPHs) derived from dry seaweeds. The present investigation was envisaged to characterize the MPHs from the red seaweed KA and a brown seaweed Sargassum wightii (SW) and also assess the effect of foliar application on maize (Zea mays) crop performance when applied alone or in proportions ranging from 0% to 100%. Two doses (0.35% and 0.7%) were compared with control. Both the MPHs contained several compounds like retronecine, tyrosyl-glycine, hexyl 2-furoate, 1-phosphatidyl-1D-myo-inositol, 12-(2,3-dihydroxycyclopentyl)-2-dodecanone, and trihomomethionine and many others that have known bioactivity for enhancing plant growth and providing stress tolerance. Both doses of MPHs enhanced crop growth and yield; however, the best response was in general observed at a lower dose. The MPH of SW at 100% gave the highest seed yield at a lower dose, which was also on par with that obtained under a lower dose of 100% KA. Other combinations, 80:20 and 40:60 KA : SW, were also found to give comparable yields. The highest dose of 100% MPH of SW was found on par with control, a phenomenon that was investigated in detail with respect to metabolites and antioxidant profile in leaves as well as membrane modeling. Higher ROS and certain sugar and organic acids were observed in 100% MPH of SW at a higher dose, although none of the antioxidant enzymes were significantly affected, nor was there any change in membrane characteristics of the leaf with respect to control as well as lower dose. Improvements in the seed yield were attributed to improved photosynthate production on account of higher dry matter accumulation in the MPH-treated plants, which may also be attributed to the presence of bioactive compounds in the biostimulants. In the future, it is imperative to direct scientific investigations towards the quantification and identification of the most effective concentrations of these compounds within MPHs to optimize plant responses. The study indicated the beneficial use of the MPHs towards increasing crop production by employing optimum dose as foliar spray to crops.

Molecular docking approaches of biomolecules extracted from red seaweed Kappaphycus alvarezii against hemolysin protein of bioluminescence disease-causing bacteria Vibrio harveyi

Shrimp culture systems are being affected by bacterial diseases particularly Vibrios. Use of therapeutic agents in shrimp culture has lead to the resistance among aquatic bacteria. Accordingly, health management becomes of major importance in aquaculture. Under this situation, developing bio-inhibitors from natural marine resources which are most appropriate, which is considered as an unmatched reservoir of several biological products. Molecular docking is suited to a major approach in structural biology and computer-assisted drug design against the proteins of disease-causative agents. In the present study, marine macroalga Kappaphycus alvarezii was used for developing inhibitors against bioluminescence disease-causing pathogenic bacteria Vibrio harveyi. K. alvarezii was collected from the Mandapam, Tamil Nadu, India. Ethyl acetate based extract of K. alvarezii was tested against the growth and virulence factors of V. harveyi during Penaeus monodon larviculture. Further K. alvarezii extract was subjected to GC–MS analysis to identify the biomolecules. The homology modelling of the virulent protein, hemolysin of V. harveyi was designed during this study. Hence, it was aimed at molecular docking against the biomolecules identified from K. alvarezii extract. During shrimp larviculture, the extract of K. alvarezii (200 μg mL−1) exhibited a reduction on Cumulative Percentage of Mortality (29.70 %) in postlarvae against the challenge of V. harveyi infection. Among the compounds docked, an inhibitory effect was observed based on docking scores and were found the highest binding affinity/inhibiting activity in Cyclotetracosane with the least energy required with a docking score of binding energy −7.66 kcal/mol, inhibition constant 0.002 mM and intermolecular efficiency −0.32 kcal/mol. Using statistical analysis, significant differences (p < 0.05) were observed between the growth and virulence factors of V. harveyi during shrimp larviculture trials. While considering these findings, it was determined that K. alvarezii extract can be replaced as an alternative bio-agents protecting against infections caused by V. harveyi and possibly other aquatic pathogenic bacteria in shrimp farming systems.

Potential utility of industrially unwanted constituent under the framework of waste to wealth: Edible salt from commercial marine red seaweed Kappaphycus alvarezii (Doty) L.M. Liao

Processing of 1000 kg of fresh Kappaphycus alvarezii yielded 25 kg salt. The optical microscopy revealed non-crystalline nature, absence of geometrical pattern; while squircle aggregates with ruffled surface were evident in SEM. Caenorhabditis elegans assay confirmed its non-toxicity; while absence of Salmonella and pesticides make it safe for human consumption. Among the macro elements, ‘K' content was highest (3792.74 ± 541.23 mg 100 g−1) and ‘Ca’ was lowest (7.01 ± 1.32 mg 100 g−1); whereas among micro element ‘Fe’ was highest (6.52 ± 1.40 mg 100 g−1) and ‘Ni’ lowest (0.14 ± 0.01 mg 100 g−1). Chromium (11.5 μg g−1) was lower than a permissible daily dose, while other heavy metals (Mo, Cu, Co, Zn, As, Cd, Hg, and Pb) were below detectable level. PXRD revealed that it has only KCl Form I. The study suggested potential economic utility of seaweed salt under the framework of waste to wealth.

Understanding the mode of action of AgroGain®, a biostimulant derived from the red seaweed Kappaphycus alvarezii in the stimulation of cotyledon expansion and growth of Cucumis sativa (cucumber).

Seaweed-based biostimulants are sustainable agriculture inputs that are known to have a multitude of beneficial effects on plant growth and productivity. This study demonstrates that Agrogain® (Product code: LBS6), a Kappaphycus alvarezii-derived biostimulant induced the expansion of cucumber cotyledons. Seven days treatment of LBS6-supplementation showed a 29.2% increase in area of expanded cotyledons, as compared to the control. LBS6-treated cotyledons also showed higher amylase activity, suggesting starch to sucrose conversion was used efficiently as an energy source during expansion. To understand the mechanisms of LBS6-induced expansion, real time gene expression analysis was carried out. This revealed that LBS6-treated cotyledons differentially modulated the expression of genes involved in cell division, cell number, cell expansion and cell size. LBS6 treatment also differentially regulated the expression of those genes involved in auxin and cytokinin metabolism. Further, foliar application of LBS6 on cucumber plants being grown under hydroponic conditions showed improved plant growth as compared to the control. The total leaf area of LBS6-sprayed plants increased by 19.1%, as compared to control. LBS6-sprayed plants efficiently regulated photosynthetic quenching by reducing loss via non-photochemical and non-regulatory quenching. LBS6 applications also modulated changes in the steady-state photosynthetic parameters of the cucumber leaves. It was demonstrated that LBS6 treatment modulated the electron and proton transport related pathways which help plants to efficiently utilize the photosynthetic radiation for optimal growth. These results provide clear evidence that bioactive compounds present in LBS6 improved the growth of cucumber plants by regulating the physiological as well as developmental pathways.

Application of brown seaweed-derived agro biostimulant to the commercial farming of the red seaweed Kappaphycus alvarezii in India: Growth enhancement and production of quality raw material

Currently global seaweed industries are facing issue with availability of raw material for processing of carrageenan due to low growth of current planting material. Use of biostimulants in seaweed cultivation is recently paid more attention due to their proven biostimulatory effect, of which, Ascophyllum marine plant extract powder (AMPEP) is a well proven biostimulant to improve the growth and quality of Kappaphycus alvarezii biomass. Hence, 500 kg of AMPEP was purchased and studied its impact on the commercial farming of K. alvarezii from April 2018 to January 2022 in India. Vegetative propagule of K. alvarezii were dipped in an AMPEP with concentration range of: 0.025, 0.05, 0.10, 0.15, 0.20 and 0.25 % for 30, 60, 90 and 120 min. Before out-planting on rafts in shallow coastal water and found that K. alvarezii responded well to a 0.1 % solution with dipping time of 60 min. The percentage of average daily growth rate (ADGR%) of AMPEP-treated plant in a 45 d grow out period was 3.50 ± 0.50 % vs a control of 1.75 ± 0.25 % for the summer and pre-monsoon months (p < 0.05) but no statistically significant differences between the treated and control plants were found during the rainy and winter seasons. Treated plants were found with low incidence of epiphytes, and disease as compared to control plants. The general appearance and health of treated Kappaphycus was good with significant differences in the yield and quality of semi-refined carrageenan (SRC) and dry weed quality (p < 0.05). The cost of AMPEP for producing of additional 1 kg of dry Kappaphycus was 0.066USD. Results of the present study is very encouraging and AMPEP can be used for the production of K. alvarezii biomass for industrial and biorefinery processing as it has been witnessed that there was 16.66 % increase in biomass production in 2021in India.

Effects of selected environmental conditions on growth and carrageenan quality of laboratory-cultured Kappaphycus alvarezii (Rhodophyta) in Fiji, South Pacific

The impacts of environmental conditions (temperature, salinity, and nutrients) on growth, semi-refined carrageenan yield, gel strengths, and viscosity were assessed on the red seaweed Kappaphycus alvarezii in laboratory culture. Results showed that K. alvarezii had a higher daily growth rate (0.94% day-1) at higher temperature (30 °C). Its semi-refined carrageenan yield was high (75.79%) at a combination of low salinity (25 ppt) and high temperature (30 °C). Conversely, gel strengths made out of semi-refined carrageenan from K. alvarezii cultured at low temperature (24 °C) demonstrated a higher compression (5.84 N) and high penetration strength (0.29 N). Highest viscosity (289.50 cP) was attained at a combination of high temperature, low salinity, and high nutrient concentration. Gels made from carrageenan of K. alvarezii grown in a higher temperature (30 °C) mixed with pineapple juice showed higher compression strength demonstrating that carrageenan extracted from cultured K. alvarezii is a good thickening agent for fruit jellies or similar food products that do not require refrigeration. This could benefit communities in rural, non-electrified communities/areas of Fiji and other South Pacific Islands that could use K. alvarezii as an alternative gelling agent in the making of food products contributing towards their food and economic security.

The Effect of Feed Supplementation with Fermented Red Seaweed (Kappaphycus alvarezii) on Growth and Survival of White Shrimp (Litopenaeus vannamei) Post-Larvae Culture

This study was aimed to investigate the effect of novel shrimp diet supplemention with fermented red seaweed Kappaphycus alvarezii on growth and survival of whiteleg shrimp (Litopenaeus vannamei) post-larvae culture. The research consisted of three consecutive steps: (1) preliminary study on Kappaphycus alvarezii fermentation, (2) feed formulation and proximate analysis, (3) performance test of commercial feed (C), commercial + 0.5% K. alvarezii (EF1), and commercial + 1.5% fermented K. alvarezii (EF2). Following 15 days of feeding, the highest biomass, specific growth rate and survival were achieved in EF2 treatment (1.60±0.21 g, 10.88±0.86%/d, 91.67±1.53%), significantly different from control (0.99±0.09 g, 7.72±0.63%/d, 47.00±5.00%) (p&lt;0.05). Overall, this study suggested that the dietary supplementation of 1.5% fermented K. alvarezii can enhance the growth and survival of whiteleg shrimp during the nursery phase.

A sulfated polysaccharide κ-carrageenan induced antioxidant defense and proteomic changes in chloroplast against leaf spot disease of tomato

Ecofriendly approaches to control plant diseases using biopolymers are gaining momentum due to their non-toxic nature to the environment. The present study elucidates the potency of a sulfated polysaccharide, κ-carrageenan, obtained from the red seaweed Kappaphycus alvarezii, as an inducer of antioxidant defense and also chloroplast proteome against leaf spot disease in tomato. к-carrageenan (0.3%) treatment was very effective in reducing disease scores in tomato plants. Fluorescent microscopy of tomato leaves stained with Uvitex 2B (a chitin specific stain) revealed that foliar application of κ-carrageenan (0.3%) reduced colonization of the pathogen Septoria lycopersici. In addition, κ-carrageenan pretreatment followed by pathogen infection recorded a higher accumulation of calcium oxalate crystals. The treatment of κ-carrageenan resulted in the induction of H2O2 and superoxide anion compared to control or S. lycopersici-infected plants. The tomato leaves treated with κ-carrageenan showed higher activity of peroxidase enzyme. Furthermore, chloroplast proteome analysis by 2D-PAGE of control, S. lycopersici-infected, κ-carrageenan-treated, and к-carrageenan treatment followed by S. lycopersici-infected leaves of tomato showed differential expression of 31 proteins, of which 11 proteins were upregulated including acid phosphatase 1-like, C- terminal processing peptidase, GATA transcription factor 5, Calvin cycle protein CP12-1, Photosystem I reaction center subunit PSAK, and subunit of cytochrome B6-F complex iron-sulfur centers. These results indicated that κ-carrageenan could be a promising inducer of antioxidant defense and modulator of chloroplast proteome in tomato plants.

Cultivation of the red seaweed Kappaphycus alvarezii using biofloc effluent

The aim of this work was to evaluate the use of effluent from a Biofloc System (BFT) as a fertilizer for the red seaweed Kappaphycus alvarezii cultivated in tanks and analyze its influence on carrageenan yield and quality. Firstly, the optimum effluent concentration and period for enrichment were determined by an in vitro study. The seedlings were then cultivated for 7 days in two different culture media: 50% von Stosch solution (V) and 25% BFT (B), both diluted in sterilized seawater. Seaweeds cultivated only in sterilized seawater were used as a control (C). After this period, all plants were grown in only sterilized seawater for a further 28 days. Seedlings from V (1.05 ± 0.02% day−1) and B (1.13 ± 0.01% day−1) showed no significant differences in growth rates, being both higher than the control (0.91 ± 0.06% day−1). Seedlings from V and B also removed a greater quantity of nitrate (58.39% and 22.97%, respectively). Seedlings from V removed 100% phosphate, while those from B removed 83.58%. The tissue nitrogen content was higher only in the V. Although no significant differences were observed among treatments in the carrageenan yield, significantly higher gel strength and viscosity were observed in B (248.85 g cm−2 and 19.89 mPa s, respectively). According to the results, BFT effluent can be used to replace von Stosch solution to grow K. alvarezii in tanks. At the same time, the seaweed, together with bacteria and microalgae from the effluent, can be an effective biofilter in IMTA systems using bioflocs.

Enhancement of Galactose Uptake from Kappaphycus alvarezii Using Saccharomyces cerevisiae through Deletion of Negative Regulators of GAL Genes

This study was aimed at enhancing galactose consumption from the red seaweed Kappaphycus alvarezii. The optimal pretreatment condition of thermal acid hydrolysis was treated with 350mM HNO3 for 60min at 121°C. The enzymatic saccharification with a 1:1 mixture of Celluclast 1.5L and Viscozyme L showed the maximum yield of glucose; 42-g/L monosaccharide concentration was obtained with the highest yield of pretreatment and enzymatic saccharification (EPS) and the lowest inhibitory compound concentration. The deletion of the GAL80, MIG1, CYC8, or TUP1 gene was performed to improve the galactose consumption rate. The strains with the deletion of the MIG1 gene (mig1Δ) showed higher galactose consumption rate and ethanol yield than other strains. High transcription levels of regulatory genes revealed that the mig1Δ relieved glucose repression. These results show that the mig1Δ enhances galactose consumption rate from K. alvarezii.

Utilization of Double Fungal Treatment by Trichoderma harzianum and Saccharomycopsis fibuligera to produce biosugar from red seaweed Kappaphycus alvarezii

Kappaphycus alvarezii is one of the natural resources that contains high carbohydrates and has the potential as an alternative raw material for the sugar industry. The aims of this research is to analyze the optimal conditions of the combination of Trichoderma harzianum and Saccharomycopsis fibuligera in degrading polysaccharides from K. alvarezii into sugar. T. harzianum and S. fibuligera were activated three times at 30° C in 2% seaweed substrate. The method used was a combination of hydrolysis and fermentation to produce evaluated bio sugar in various concentrations of inoculum (5%, 10%, 15%, and 20%) and time (0 hour, 24 hours, 48 hours, and 72 hours). Based on the results, hydrolysis with an inoculum concentration of 20% for 24 hours showed the highest total sugar production. Followed by fermentation with S. fibuligera which produced glucose and galactose which is 1.74 g/L and 9.93 g/L. In conclusion, this research demonstrates the ability of T.harzianum and S. fibuligera to convert carbohydrates from K. alvarezii to produce biosugar through a combination of hydrolysis and fermentation methods.

Studies on the development and characterization of bioplastic film from the red seaweed (Kappaphycus alvarezii).

Seaweeds rich in polysaccharides are considered commercially important because of their wide range of industrial applications. In this study, the red seaweed Kappaphycus alvarezii was used for bioplastic film production. Plasticizer polyethylene glycol (PEG) to seaweed biomass ratio was optimized and a thin bioplastic film with higher tensile strength was produced. The films obtained were characterized by its thickness, tensile strength, colour (L, a, b), elongation at break (EAB), water vapour transmission rate (WVTR) and oxygen transmission rate (OTR). TG-DSC, AFM, SEM and FTIR spectroscopy analysis were performed to assess the composition, phase transitions and chemical reaction capabilities of the film. The bioplastic film obtained from 4% K. alvarezii (whole seaweed) showed better physical and mechanical properties, whereas TG-DSC, FTIR and AFM showed similar kind of bioplastic properties in all the concentrations. Decrease in OTR was observed against decreasing wall thickness of the film. The present study suggests that the seaweed would be a potential alternate source for bioplastic production which may reduce the usage of non-degradable plastics.

Can foliar application of seaweed sap improve the quality of rice grown under rice–potato–greengram crop sequence with better efficiency of the system?

Producing rice grain with superior quality along with higher productivity is very much needed to improve the food and nutrient security. Therefore, this experiment was designed to determine the effect of seaweed sap derived from the red seaweed Kappaphycus alvarezii (K–sap) on quality improvement of rice grown under rice–potato–greengram crop sequence. The experiment consisted of 12 treatments using K–sap and chemical fertilizer application in a randomized complete block design replicated thrice. The study was conducted at Uttar Chandamari village, India, during two consecutive years of 2013–2014 and 2014–2015. It was found that the maximum amounts of physical quality attributes, viz. hulling, milling, head rice recovery and biochemical quality attributes like amylose and carbohydrate contents of rice, were found with 7.5% K–sap + 100% RDF (recommended dose of fertilizer). This treatment also exhibited the highest system productivity. Concerning the efficiency of the system, it was documented that the maximum values of agronomic efficiency, physiological efficiency and recovery fraction of nutrient used were recorded in 7.5% K–sap + 50% RDF, 0.0% K–sap + 50% RDF and 7.5% K–sap + 100% RDF, respectively. It was also evaluated that the foliar spraying of K–sap at 2.5, 5 and 7.5% rate along with 100% RDF showed the positive nitrogen (N) balance of the system. From this study, it was observed that the foliar application of K–sap is able to improve the quality of rice besides improving yield and better system efficiency. Positive N balance was also accomplished through the application of K–sap in combination with RDF.

Antioxidant and antibacterial activity of red seaweed Kappaphycus alvarezii against pathogenic bacteria

Seaweeds can produce variety of bioactive components for the benefits of humans. Malaysia is one of the countries to produce red seaweeds, which are popular secondary metabolites. Kappaphycus species, largest tropical red algae exhibit the high growth rate. It was reported that its biomass can grow double in just 15 to 30 days. Therefore, this investigation emphasized on two extraction methods such as hot water and ethanolic Soxhlet extraction to extract the bioactive compounds from Kappaphycus alvarezii. Both of theseextractions were screened to produce antimicrobial and antioxidants compounds. Total phenolic content and ferric reducing assays were employed to quantify antioxidant properties. Whereas, the disc diffusion assays were used to study antibacterial activity. The results reported the highest phenolic content for ethanolic extract (20.25 ± 0.03 mg gallic acid equivalents per gram of extract). On the other hand, the value of phenolic content was slightly decreased 19.1 ± 0.81 mg gallic acid equivalents per gram of extract for the hot water extract. It was also found that both the extracts were potentially capable of balancing reactive oxygen species. Disc diffusion assay results indicated that the extract of red alga K. alvarezi were more efficient against B. cereus. Among the fatty acids determined levoglucosenone and 4-Pyridinemethanol were present in high percentages in hot water extract whereas Hexamethyl- cyclotrisiloxane followed by 1, 2, 5- Thiadiazole-3-carboxamide, 4-[(2-chloroethyl) amino]-N-(2-hydroxyethyl) were present in ethanolic extract of K. alvarezi. The present study concluded that, hot water extracts of K. alvarezii can be used for large scale production of bioactive compounds utilizing an easily available potential seaweed. Future research of red seaweed will be highly important for pharmaceutical and medicinal field as well as a homogenizer in milk products, toothpaste and jellies in other industrial applications.

Spinogenesis and Synaptogenesis Effects of the Red Seaweed Kappaphycus alvarezii and Its Isolated Cholesterol on Hippocampal Neuron Cultures.

Neurotrophic factors promote the formation of spines and synapses in neuron development and maintenance. Synaptic connections enhance memory in the brain. In this study, the effects of Kappaphycus alvarezii ethanolic extract (EKA) and its isolated cholesterol (iCHOL) on spinogenesis and synaptogenesis of hippocampal neurons were evaluated. Compared with the vehicle, both EKA and iCHOL significantly promoted generation of dendritic filopodia (2.4- and 2.2-fold, respectively) and spine (1.7- and 1.4-fold) formations in spinogenesis; they also increased presynaptic (3.6- and 2.6-fold), postsynaptic (2.5- and 2.9-fold), and cocolonized (3.8- and 3.0-fold) puncta, which enhances synaptic function (P< 0.05). Further, EKA- and iCHOL-treated neurons showed significantly improved functional presynaptic plasticity (1.6- and 1.4-fold, respectively, at 17 days in vitro; P<0.05). These results indicate that K. alverezii facilitates neuronal development, and support its use as a functional food to reduce neurological disorders and prevent brain aging via helping to reconstruct partially damaged neural networks.

Physico-Chemical Properties of Semi Refined Carrageenan (SRC) Kappaphycus alvarezii from Karimun, Riau Islands, Indonesia

Carrageenan is a non-fish fishery product derived from the extraction of red seaweed (Rhodophyceae) Kappaphycus alvarezii. It is generally used in the field of cosmetics industry , textiles, food, pharmaceutical, stabilizer and gel formation. The objective of this study was to determine the physico-chemical properties of semi refined carrageenan (SRC) on red seaweed (Kappaphycus alvarezii). The research phase included the preparation of raw materials for Kappaphycus alvarezii and making SRC, then followed by physico-chemical analysis, yield, moisture content, ash content, acid insoluble ash content, gel strength, viscosity, melting point, and cumulative point. The Physico-chemical SRC observations were yields of 24.80%, the water content of 19.20%, ash content of 16.34%, insoluble ash content in acid 0.31, the strength of gel 376.46 g/cm 2 , viscosity 139.47 cP, melting point 55.70 0 C, graduation point 38 0 C.