Kappaphycus Striatum Research Articles

Growth Rate of Kappaphycus striatum var cottonii at Different Positions of the Cultivation Lines to the Direction of Water Current

Growth Rate of Kappaphycus striatum var cottonii at Different Positions of the Cultivation Lines to the Direction of Water Current

A comparison of nutritional values of Kappaphycus alvarezii, Kappaphycus striatum, and Kappaphycus spinosum from the farming sites in Gorontalo Province, Sulawesi, Indonesia

Kappaphycus is a red alga which contains carrageenan. Kappaphycus alvarezii is the most popular seaweed known as cottoni in addition to several other species, such as K. spinosum (spinosum) and K. striatum (sacol). These three species of Kappaphycus were collected from farming sites of Kappaphycus in Popayato, Pohuwato district, Province of Gorontalo, Sulawesi, Indonesia. The nutritional values of these three Kappaphycus were assessed based on the analysis on their chemical composition, including ash, lipid, crude fiber, protein, carbohydrate, vitamin C, gel strength, and mineral contents including Ca, Na, and Fe, as well as fatty acids. There were no significant differences in the nutritional values of K. alvarezii, K. striatum, and K. spinosum from farming sites of Gorontalo Province, Sulawesi. However, K. alvarezii had the highest value of carbohydrate, protein, vitamin C, and gel strength, whereas K. spinosum had the highest contents of Ca, Na, and omega-6 fatty acids. Additionally, K. striatum had the highest moisture, crude fiber, Fe, and omega-3 fatty acid. It is suggested that each Kappaphycus is a potential source of important nutrition for human and animal health.

Cloning cDNA sequence coding the KSA-1 lectin from red alga Kappaphycus striatum cultivated in Vietnam

The red alga Kappaphycus striatum is economically important food species and extensively cultivated in Vietnam. This cultivated alga may thus now contribute as a source of not only carrageenan, but also other bioactive compounds for biochemical and medicinal uses. KSA-1 lectin from this alga has been evaluated for biochemical properties, including high-mannose binding specificity, N-terminal amino acid sequence and molecular mass. In this study, we have cloned the cDNA clone encoding the lectin KSA-1. The full-length sequence of cDNA clone of KSA-1 lectin encoded a polypeptide of 268 amino acids including initiating methionine, with four tandemly repeated domains of about 67 amino acids, and sharing 43% sequence identity. The primary structure and the amino acid residues interact with mannopentaose core structure per a repeat domain of the KSA-1 lectin highly resemble and match those of anti-virus the lectin family in lower organinsms, including bacteria [BOA from Burkholderia oklahomensis EO147, MBHA from Myxococcus xanthus and PFA from Pseudomonas fluorescens Pf0-1], cyanobacteria [OAA from Oscillatoria agardhii] and red algae [ESA-2 from Eucheuma serra, EDA-2 from Eucheuma denticulatum, KAA-1 and KAA-2 from Kappaphycus alvarezii and KSA-2 from K. striatum]. Analysis of predicted secondary structure of KSA-1 showed twenty β-strands. Each repeated domain comprises the five β-strands and matches with number of β-strands of BOA lectin. Therefore, the red alga K. striatum could be a good source for application in biomedicine and biochemistry as materials for production of the functional lectin(s).

Composition and characteristics of continuous enzymatic hydrolysis products from Kappaphycus striatum

The oligosaccharide κ-carrageenan is sulfated carbohydrate with various bioactivities. In order to prepare this functional oligosaccharide directly from the red alga Kappaphycus striatum, a continuous enzymatic hydrolysis method was used to digest K. striatum. The yield of oligosaccharide (product KS-3) reached 43.26 g per 100 g of dry algae, and the product was identified as high-purity sulfated oligosaccharides mainly composed of κ-carrageenan hexasaccharide ([A-G4S]3) and octasaccharide ([A-G4S]4). The by-products generated during the preparation of oligosaccharide were also collected. The yield of insoluble product (KS-1) was 14.46 g per 100 g of dry algae, it was rich in protein (63.23%) and the content of essential amino acid was close to 40 g per 100 g of dry protein. The yield of soluble high-molecular weight product (KS-2) was 18.04 g per 100 g of dry algae, it was mainly composed of soluble dietary fibers (69.49%) and showed perfect expansion characteristics. We describe here a novel method for the preparation of oligosaccharides directly from seaweed, which is also beneficial for the comprehensive utilization of seaweed.

Kandungan Makronutrien Rumpai Laut Merah Kappaphycus alvarezii dan Kappaphycus striatum

Seaweed contains various nutrients that has the potential to be a source of nutritious food, but only a few studies done on the red seaweeds in Malaysia. Therefore, this study was conducted to determine the macronutrients content, amino acid profile and fatty acid component in Kappaphycus alvarezii and Kappaphycus striatum. The study found that the range of moisture, fat, ash, protein, fiber and carbohydrates content for both red seaweeds were 6.9% - 7.3%, 0.5% - 2.6%, 29.4% - 30.9%, 2.5% - 5.7% , 5.3% - 5.5% and 50.1% - 53.3% respectively. A total of 16 amino acids were identified in which the essential amino acid for K. alvarezii and K. striatum were 41.11% and 36.15% respectively. A total of 34 fatty acids were identified in which the content of saturated fatty acids (SFA) was the highest (42.7% - 72.8%), followed by mono-unsaturated fatty acid (MUFA) (13.8% - 36.2%) and polyunsaturated fatty acids (PUFAs) was the lowest (13.5% - 21.2%). In conclusion, this study suggest that K. alvarezii and K. striatum are potentially be used as raw materials or food ingredients to improve the nutritional value of the human diet. DOI : http://dx.doi.org./10.17576/JSKM-2017-1502-03

Light absorption and impacts of low salinities on photosynthetic behaviour in the epiphytic alga Neosiphonia savatieri (Rhodomelaceae, Rhodophyta)

Filamentous epiphyte outbreaks, a serious problem in the commercial cultivation of Kappaphycus/Eucheuma, are often triggered by large changes in abiotic factors. However, the physiological characteristics of epiphytes are poorly understood. In this study, the main pigment contents of Neosiphonia savatieri and its healthy host strains, including green thalli of Kappaphycus striatum (G-KS), brown and green thalli of Kappaphycus alvarezii (B-KA, G-KA), were quantified. The light absorption capacities of lipid- and water-soluble pigments of these seaweeds were also measured. Photosynthetic parameters, including pigment content and fast chlorophyll a fluorescence kinetics, were further studied in N. savatieri exposed to different salinities (16–34 psu) for 10 h in an outdoor experiment. The phycobiliprotein (PBP), Chl-a, and carotenoid contents of N. savatieri were comparatively higher than the hosts, with the values of 2.50, 0.29, and 0.12 mg g−1 (fw), respectively. The mean extinction coefficients of lipid- and water-soluble pigments in N. savatieri were both higher than G-KS, B-KA, and G-KA in the 400–700 nm bands. Salinity of 28 psu increased the pigment contents of the epiphyte, and 16–22 psu did not have a negative impact. Polyphasic fluorescence transients revealed that salinities at 22–28 psu were beneficial to photosynthetic electron transport, mainly attributed to the enhancement of energy absorption per active PSII reaction centre. Given these observations, N. savatieri has a higher light-harvesting capacity and better tolerance to low salinities. These two physiological properties made N. savatieri well suited to the low light and hypo-saline conditions that are frequently triggered by fluctuations in abiotic factors.

Thermal and PAR effects on the photosynthesis of Eucheuma denticulatum and Kappaphycus striatus (so-called Sacol strain) cultivated in shallow bottom of Bali, Indonesia

Photosynthetic responses to various temperature and PAR conditions of two carrageenophytes, Eucheuma denticulatum and Kappaphycus striatus (so-called Sacol strain), cultured in shallow areas of Bali, Indonesia, were examined using dissolved oxygen measurements and pulse–amplitude-modulated (PAM) fluorometry. Net photosynthesis–irradiance (P–E) curves at 26 °C revealed that the values of Pmax for E. denticulatum and K. striatus were 13.76 and 5.02 μg O2 gfw−1 min−1 (12.38–15.12 and 4.55–5.50 μg O2 gfw−1 min−1, 95 % Bayesian prediction interval (BPI)), respectively. Photoinhibition was not observed even at 1000 μmol photons m−2 s−1. Gross photosynthesis and respiration characteristics over a range of temperatures (8–36 °C) revealed optimum temperature for photosynthesis to be 31.1 °C for E. denticulatum, and 31.6 °C for K. striatus. These characteristics of photosynthesis indicate that both farmed seaweeds are well adapted to the light and temperature conditions of the cultivation site. However, studies on longer timescales for photochemical efficiency, photosynthesis, and respiration are still needed to determine their limits of tolerance. We also hypothesize that higher values of photosynthetic parameters for E. denticulatum suggest that this species is relatively superior in productivity under optimal conditions, conditional on the farming method.

Antioxidant responses and photosynthetic behaviors of Kappaphycus alvarezii and Kappaphycus striatum (Rhodophyta, Solieriaceae) during low temperature stress.

Background Kappaphycus are farmed in tropical countries as raw material for carrageenan, which is widely used in food industry. The sea area available for farming is one limiting factor in the production of seaweeds. Though cultivation is spreading into subtropical regions, the lower seawater temperature is an important problem encountered in subtropical regions for the farming of Kappaphycus. This research of physiological response to low temperature stress will be helpful for screening Kappaphycus strains for growth in a lower temperature environment.ResultsResponses of antioxidant systems and photosystem II (PSII) behaviors in Kappaphycus alvarezii and Kappaphycus striatum were evaluated during low temperature treatments (23, 20, 17 °C). Compared with the controls at 26 °C, the H2O2 concentrations increased in both species when the thalli were exposed to low temperatures (23, 20, 17 °C), but these increases were much greater in K. striatum than in K. alvarezii thalli, suggesting that K. striatum suffered more oxidative stress. The activities of some important antioxidant enzymes (e.g. superoxide dismutase and ascorbate peroxidase) and the hydroxyl free radical scavenging capacity were substantially higher at 23, 20 and 17 °C than at the control 26 °C in K. alvarezii, indicating that the antioxidant system of K. alvarezii enhanced its resistance to low temperature. However, no significant increases of antioxidant enzymes activities were observed at 20 and 17 °C in K. striatum. In addition, both the maximal efficiency of PSII photochemistry (FV/Fm) and the performance index (PIABS) decreased significantly in K. striatum at 23 °C, indicating that the photosynthetic apparatus was damaged at 23 °C. In contrast, no significant decreases of either FV/Fm or PIABS were observed in K. alvarezii at 23 °C.ConclusionsIt is concluded that K. alvarezii has greater tolerance to low temperature than K. striatum.

Molecular assessment of invasive CarrageenophyteKappaphycus alvareziifrom India based on ITS-1 sequences

This is the first report on the molecular systematic characterization of the invasive red alga Kappaphycus alvarezii in India. Cultivated for the production of carrageenan around the Gulf of Mannar, southeast India, this exotic alga is causing havoc in coastal ecosystems by invading the habitats of a number of endemic species, especially soft corals. We have sequenced the nuclear ribosomal DNA internal transcribed spacer 1 barcode of this introduced species. In our phylogenetic analyses using Bayesian inference and maximum likelihood, this alga clustered within a well-supported clade of K. alvarezii of mixed geographic origin. Phylogenetic analyses were congruent in their separation of K. alvarezii and Kappaphycus striatum. Analyses also suggest that this species might have originated in the Malay Archipelago and spread elsewhere. Our results provide insights into the evolutionary and biogeographic patterns of this alga around the world.

Cloning and characterizing cDNA sequences coding high-mannose n-glycan binding lectins from cultivated red algae Eucheuma denticulatum and Kappaphycus striatum

The red algae, Eucheuma denticulatum and Kappaphycus striatum have been widely cultivated in Vietnam as a source of carrageenophytes for industry. In the past, biochemical properties of lectins isolated from these algae has been characterized and evaluated extensively. However, gene coding for such lectins isn’t studied yet. In this study, their full length cDNA is amfplified using cDNA ends (RACE) methods. Sequence analysis revealed that cDNA of EDA-2 from E. denticulatum consisted of 1,158 bp containing 103 bp of a 5'untranslated region, 248 bp of 3'untranslated region, and 807 bp of an open reading frame; and cDNA of KSA-2 from K. striatum consisted of 1174 bp containing 94 bp of the 5'-untranslated region, 273 bp of 3'untranslated region and 807 bp of the open reading frame. The cDNA of both EDA-2 and KSA-2 encoded for a polypeptide of 269 amino acids including an initiating methionine, but differed in sequences and molecular masses. The deduced amino acid sequences of EDA-2 and KSA-2 composed of four tandem repeated domains with about 67 amino acids each. The primary structure of EDA-2 and KSA-2 is highly similar to those of the high mannose N-glycan specific lectins including OAA from cyanobacterium, BOA, MBHA and PFA from bacteria, and ESA-2, KAA-1, KAA-2 from macro red algae, which showed strong anti-HIV and anti-influenza virus activities. These results indicate that these cultivated algae are becoming promising materials for production of anti-virus reagent or functional food that can prevent virus infection in future.

Growth and biochemical composition of Kappaphycus (Rhodophyta) in customized tank culture system

The study was conducted to determine the growth and biochemical composition of Kappaphycus cultivated in a customized tank culture system. Two red seaweed species (Kappaphycus alvarezii and Kappaphycus striatum) were selected and cultivated using suspension culture method in the tank. Three cycles of 40-day culture trials were performed during September to December 2014, and both K. alvarezii and K. striatum were successfully grown in the tank. This is the first report on the success of seaweed culture in Malaysia involving land-based facility. Interestingly, K. striatum was found to grow better than K. alvarezii in the tank. The daily growth rate (DGR) and daily weight productivity (DWP) of K. alvarezii ranged from 1.96 ± 0.08 to 2.29 ± 0.11 % day−1 and 3.70 ± 0.20 to 4.55 ± 0.34 g DW m−2 day−1, and those of K. striatum ranged from 2.25 ± 0.06 to 2.96 ± 0.02 % day−1 and 4.48 ± 0.19 to 6.17 ± 0.18 g DW m−2 day−1, respectively. These values were influenced by the changes in the water quality variables during the culture period. On the other hand, the biochemical composition of K. alvarezii and K. striatum was not significantly different (p > 0.05) from each other. Both growth and biochemical composition of K. alvarezii and K. striatum in the present study were comparable with those cultured in the open sea. In conclusion, the findings indicate the ability of Kappaphycus to grow well in land-based cultivation system which can be further explored to support the development of local seaweed farming industry especially for the high-quality seed production.

Development and application of single locus genomic molecular marker for Kappaphycus and Eucheuma (Solieriaceae, Rhodophyta) seaweeds

The division Rhodophyta includes members from the commercially important genera Kappaphycus and Eucheuma. The efficient cultivation of seaweeds depends upon the development of genomic molecular markers which can be applied to detect varietal differences and select strains which exhibit ideal growth characteristics. We developed 117 single loci DNA markers from shotgun genomic libraries derived from Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum and tested them across twelve phenotypes which are commercially cultured in Sabah, Malaysia. Sixteen of the markers amplified across all varieties of Kappaphycus implying a shared genetic identity. Eight of the markers could successfully differentiate between varieties of Eucheuma and Kappaphycus on the basis of DNA fingerprinting profiles. These markers will serve as resource for the identification and selection of red algae for commercial cultivation and their application can be extended to marker assisted selection (MAS) and hybrid development.

Increased use of non-native algae species in the diet of the Green Turtle (Chelonia mydas) in a primary pasture ecosystem in Hawaii

The Green Turtle, Chelonia mydas, has modified its feeding behavior over the past 36 years to include the increasing abundance of non-native algae growing in the greater Kaneohe Bay area of Oahu, Hawaii. Changes in diet of the Turtles are correlated with an increase in abundance of non-native algae. Turtles are eating 135 species of marine vegetation including the following seven non-native species: Acanthophora spicifera, Hypnea musciformis, Gracilaria salicornia, Eucheuma denticulatum, Gracilaria tikvahiae, Kappaphycus striatum and Kappaphycus alvarezii. Non-native algae now represent 0.64 proportion of the Turtle diet. The present study for the additional 8 years 2005–2012, shows the utilization of non-native species for food has increased 24% since the last study that included 28 years 1976–2005. Average time for the Turtles to make the shift to non-native species is 10–12 years for the more invasive species and 20–30 years for the slower growing species. During this same time period the numbers of C. mydas, body size, and growth rates have also increased, partly due to the increased abundance of the additional non-native food items. This study verifies that the trend of Turtles eating higher amounts of non-native algae in Kaneohe Bay is now stronger than first reported in 2009.

Differences in photosynthetic behaviour of Kappaphycus alvarezii and Kappaphycus striatus during dehydration and rehydration

The kappa-carrageenan-producing seaweed Kappaphycus striatus is different from K. alvarezii in that it grows well in the intertidal zone, where the thalli are exposed periodically to dehydration and rehydration. To investigate the specific tolerance mechanism of K. striatus, the photosynthetic behaviour of K. alvarezii and K. striatus exposed to osmotic variation was compared. K. striatus had a lower dehydration rate in the dark treatments and a higher rehydration rate in both the dark and light treatments as compared with K. alvarezii. The FV/FM of K. striatus was significantly higher than that of K. alvarezii during the process of dehydration and rehydration in both the light and dark treatments. The increase in amplitude of JIP-test fluorescence parameters VK, VJ and VI of K. striatus was smaller than that of K. alvarezii during the dehydration process in both the light and dark treatments. The increased amplitude of VK, VJ and VI in K. striatus was significantly lower than that in K. alvarezii when they were rehydrated in the dark treatments. Therefore, during the process of dehydration and rehydration, the tolerance of the oxygen evolving complex, the ability to balance photosynthetic light absorption and energy utilization, as well as the tolerance of PSII reaction centres were relatively higher in K. striatus compared with K. alvarezii. Such an increased tolerance of PSII may help to improve the tolerance of the whole plant to dehydration.

Co-culture of sea cucumber Holothuria scabra and red seaweed Kappaphycus striatum

Commercially valuable sea cucumbers are potential co-culture species in tropical lagoon environments, where they may be integrated into established aquaculture areas used for seaweed farming. In the current study, wild-caught juvenile sea cucumbers, Holothuria scabra, and red seaweed Kappaphycus striatum were co-cultured on Zanzibar, United Republic of Tanzania. Sea cucumbers (97 g � 31 SD, n = 52) were cultured in mesh enclosures at initial cage stocking densities of 124 � 21 SD and 218 � 16 SD g m � 2 under seaweed culture lines. Over 83 days, individual growth rate (1.6 g d � 1 � 0.2 SD) of sea cucumbers at low stocking density was significantly higher (v 2 = 8.292, d.f. = 1, P= 0.004) than at high-stocking density (0.9 g d � 1 � 0.1 SD). Seaweed individual growth rates [6.27 (� 0.3 SE) g d � 1 ] were highest in co-culture with sea cucumber at low density but did not differ significantly from high sea cucumber density or seaweed monoculture treatments (v 2 = 3.0885, d.f. = 2, P = 0.2135). Seaweed growth varied significantly (v 2 = 35.6, d.f. = 2, P < 0.0001) with sampling period, with the final sampling period resulting in the highest growth rate. Growth performance for seaweed and sea cucumbers (v 2 = 3.089, d.f. = 2, P = 0.21 and v 2 = 0.08, d.f. = 1, P = 0.777 respectively), did not differ significantly between monoculture and co-culture treatments, yet growth in co-culture was comparable with that reported for existing commercial monoculture. Results indicate H. scabra is a highly viable candidate species for lagoon co-culture with seaweed. Co-culture offers a more efficient use of limited coastal space over monoculture and is recommended as a potential coastal livelihood option for lagoon farmers in tropical regions.

Ecological risk assessment of the introduction of exotic carrageenophytes in the tropical Western Atlantic

The potential risks of cultivating carrageenophyte genera for commercial purposes in the circumtropical belt are debated. However, species introductions of two such genera, Kappaphycus Doty and Eucheuma J. Agardh, have been reported in 30 different locations in this region over the last 30 years. On several occasions, these introductions did not adequately evaluate potential environmental risks or were conducted without approval from local regulatory bodies. In the present paper, a working protocol is proposed for the quarantine and assessment of the possible effects of the introduction of Kappaphycus alvarezii and Kappaphycus striatus to shallow marine ecosystems of the tropical Western Atlantic. This protocol is based on field data following from the introduction of eucheumoids onto the Cuban shelf in the early 1990s. It was demonstrated that the propagation of either carrageenophyte in oligotrophic waters of the Cuban Archipelago did not pose a potential risk to the region’s biodiversity due to the synergic combination of high herbivory and low rates of growth. Physical features of the substrate and depth were the most important regulators of grazing. These environmental conditions restrict potential cultivation sites in the Cuban Archipelago to a few small regions where nutrient pulses are well established. In these areas, when the canopy of cultivated carrageenophytes is sufficiently high, a significant effect on benthic communities is observed. In consideration of the need to protect places with high intrinsic value, this fact should be considered during site selection.

The mitochondrial genome of the red alga Kappaphycus striatus (“Green Sacol” variety): Complete nucleotide sequence, genome structure and organization, and comparative analysis

The complete mitochondrial (mt) DNA sequence of the rhodophyte Kappaphycus striatus (“Green Sacol” variety) was determined. The mtDNA is circular, 25,242 bases long (A+T content: 69.94%), and contains 50 densely packed genes comprising 93.22% of the mitochondrial genome, with genes encoded on both strands. Through comparative analysis, the overall sequence, genome structure, and organization of K. striatus mtDNA were seen to be highly similar with other fully sequenced mitochondrial genomes of the class Florideophyceae. On the other hand, certain degrees of genome rearrangements and greater sequence dissimilarities were observed for the mtDNAs of other evolutionarily distant red algae, such as those from the class Bangiophyceae and Cyanidiophyceae, compared to that of K. striatus. Furthermore, a trend was observed wherein the red algal mtDNAs tend to encode lesser number of protein-coding genes, albeit not necessarily shorter, as the organism becomes more morphologically complex. This trend is supported by the phylogenetic tree inferred from the concatenated amino acid sequences of the deduced protein products of cytochrome c oxidase subunit genes (cox1, 2, and 3).

Genetic diversity of Kappaphycus Doty and Eucheuma J. Agardh (Solieriaceae, Rhodophyta) in Southeast Asia

The commercial importance of carrageenophytes Kappaphycus and Eucheuma is well known, with much interest in terms of cultivation, marketing, and research. Considering the many lucrative prospects, these red seaweeds were introduced into various parts of the world for farming, where merely a few were comprehensively documented. Despite being extensively cultivated throughout Southeast Asia, the genetic diversity of Kappaphycus and Eucheuma is poorly studied, where heavy reliance is placed on the use of local or commercial names for identifications. This study used the mitochondrial-encoded cox1 and cox2–3 spacer genetic markers to investigate the Kappaphycus and Eucheuma haplotypes, cultivated and wild, available throughout Southeast Asia. Concatenated cox1–cox2–3 spacer datasets were also analyzed. The near full-length cox1 gene is preferred at revealing the genetic diversity of Kappaphycus and Eucheuma, provided a larger reference database is available. Both molecular markers were capable of delineating common members of the genus Kappaphycus (i.e., Kappaphycus alvarezii, Kappaphycus striatus, and Kappaphycus cottonii) and Eucheuma denticulatum, and revealed interesting genotypes and new species which may be potential alternatives to the common cultivars as well as materials for research. The relative scarcity of Eucheuma species is discussed and future sites for sampling are recommended.

Cultivation and utilisation of red seaweeds in the Western Indian Ocean (WIO) Region

Seaweed farming in the Western Indian Ocean (WIO) Region is carried out in a number of countries, most of them farming Eucheuma denticulatum, Kappaphycus alvarezii and Kappaphycus striatum. These species are farmed mostly in Tanzania with limited production in Madagascar, Mozambique and Kenya; current production (2012) stands at 15,966 t (dry weight) year−1 of Eucheuma and Kappaphycus, valued at US$ 4.2 million with 95 % of this tonnage coming from Tanzania. Other countries in the region have limited or no seaweed production owing to problems of epiphytes, ice ice and markets. The problem of epiphytes coupled with ice ice that WIO countries are facing causes die-off of Kappaphycus which is the preferred species in foreign markets for its thicker gel, kappa carrageenan (vs. the weaker iota carrageenan from Eucheuma). New efforts are put to curb these problems including moving seaweed farms to deeper waters and cultivation trials of other carrageenophytes as well as agar-producing species, agarophytes. Research work has been initiated to evaluate Gracilaria and Hypnea farming and processing in Tanzania, the Republic of Mauritius and Mayotte. Gracilaria farming is at experimental stages as a biofilter of fishpond effluents and as potential species for the production of agar with growth rates of 1.5–1.9 % day−1. Hypnea farming is only being initiated in Mauritius and Mayotte at present. Other innovations including value addition by making various seaweed products and encouraging the consumption of seaweed as food at least in Tanzania and Mauritius are increasing further the importance of the seaweed farming and processing industry in the WIO Region.

Antibacterial activity of seaweed (Kappaphycus) extracts against infectious pathogens

Natural products represent a potential source for the search of new drug. Among them, seaweeds can be highlighted because of its abundance in nature and richness in bioactive compounds. Screening of these for antimicrobial compounds is vital due to increasing demand of therapeutic drugs in treatment of pathogenic infection. In this study, the antibacterial activity of seaweeds (Kappaphycus alvarezii, Kappaphycus striatum Kappaphycus alvarezii (Doty) Doty ex P. C. Silva and Kappaphycus striatum (F.Schmitz) Doty ex P. C. Silva. was tested against human bacterial pathogens (Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, Staphylococcus aureus, Streptococcus pyogenes, Serratia sp. and Proteus sp.). Different seaweeds extracts (acetone, benzene, butanol, chloroform, ethanol, ethyl acetate, hexane, isoamyl alcohol, methanol, propanol and toluene) were evaluated for antibacterial activity by agar well diffusion methods. In the present study, the best results were obtained for chloroform and isoamyl alcohol extracts, which presented inhibition zones for the majority of the pathogens. The K. striatum species activity was high when compared with K. alvarezii. The chloroform and isoamyl alcohol extracts showed maximum activity and showed highest zone of inhibition of 22 and 20 mm, respectively. The results indicate significant capacity and future scope for the use of seaweed against a wide range of microbial populations. Key words: Seaweed, antibacterial activity, antimicrobial agent, Kappaphycusalvarezii, Kappaphycus striatum.