Digital library

  • Elevated concentration of radioactive potassium in edible algae cultivated in Malaysian seas and estimation of ingestion dose to humans
    Although the various benefits of seaweeds are well recognised, potential health hazards are much less well researched, as an instance the possible presence of concentrated levels of natural radionuclides. In present work the concentrations of natural radionuclides in seaweed cultivated in Malaysian seas are assessed using conventional HPGe γ-ray spectrometry. An edible species of seaweed has been collected from several seaweed farms located along coasts of the Andaman and South China Sea. Activity concentrations of 226Ra, 228Ra and 40K in samples collected from Langkawi are observed to be greater than those from Sabah, while 40K radioactivity levels (2.2E3 ± 100 – 3.8E3 ± 180 Bq kg−1) in all samples are noted to be well above the world average value of between 400 and 580 Bq kg−1. The estimated amount of total potassium is in the range 68 – 120 g (kg of seaweed)−1 and 53–106 g kg−1 obtained via ICP-OES, which are in line with data for New Zealand seaweed of between 43.7 and 123 g kg−1. The estimated total effective dose of 84 μSv·y−1 is lower compared to a global internal dose of 290 μSv·y−1 as reported by UNSCEAR. Accordingly, the mean cancer risk from such consumption was also estimated to be slightly lower (1.92 × 10−3) compared to the ICRP cancer risk factor of 2.5 × 10−3 based on the additional annual dose limit of 1 mSv for a member of the general public, which gives an annual mortality probability of 10−5 (1 in 100,000; ICRP, 1991). Although posing

    a low risk health hazard, periodic monitoring of natural radioactivity in foodstuff remains important in seeking to ensure the radiological safety of the public.

    Author(s): D.A. Bradley, Yusoff Mohd. Amin, Nurul 'Adillah Binti Heffny, Mayeen Uddin Khandaker

  • Elevating the Aquaculture Debate

    Aquaculture has been the subject of two recent high profile reports. The first, entitled Blue Frontiers, begins by asserting ‘There is a pressing need to elevate the debate on the future of aquaculture and to place this in the context of other animal food production systems, including wild capture fisheries’. The second report made the front cover of Time Magazine and poses the question ‘Can farming save the last wild food?"

    Author(s): John Forster

  • ELICITATION OF ASIATIC ACID IN CENTELLA ASIATICA USING KAPPAPHYCUS ALVAREZII

    Centella asiatica is an endangered medicinal herb which used in the preparation of herbal drugs mainly due to the presence of four pentacyclic triterpene which are asiatic acid, asiaticoside, madecassic acid and madecassoside. It’s over exploitation necessitates the development of conservation strategies and enhanced the production of secondary metabolites. In present study, the effect of various concentration of seaweed Kappaphycus alvarezii elicitor was used to increase the amount of asiatic acid production in C. asiatica. Four difference concentration of seaweed elicitor was treated in C. asiatica which are 0 g/L, 2g/L, 4g/L and 8g/L. They are harvested at day 0, 7, 14 and 21 and soak with methanol to obtain crude brown extract. The amount of asiatic acid containing in the samples was analyzed by HPLC and area under the curve of retention peak was calculated by using a formula. The diameter of leaf, number of new shoots and flowers were measured during successive stages of development. In conclusion, K. alvarezii can increase the production amount of asiatic acid in C. asiatica at shorter time, which at day 14, concentration of 4g/L and 8 g/L are the best while the additional of certain concentrations of seaweed elicitor can induce flowering in C. asiatica

    Author(s): PUTRI NUR HALIMAH BT ABDUL RAHMAN PUTRA

  • Emerging Technologies for the Extraction of Marine Phenolics: Opportunities and Challenges

    Natural phenolic compounds are important classes of plant, microorganism, and algal secondary metabolites. They have well-documented beneficial biological activities. The marine environment is less explored than other environments but have huge potential for the discovery of new unique compounds with potential applications in, e.g., food, cosmetics, and pharmaceutical industries. To survive in a very harsh and challenging environment, marine organisms like several seaweed (macroalgae) species produce and accumulate several secondary metabolites, including marine phenolics in the cells. Traditionally, these compounds were extracted from their sample matrix using organic solvents. This conventional extraction method had several drawbacks such as a long extraction time, low extraction yield, co-extraction of other compounds, and usage of a huge volume of one or more organic solvents, which consequently results in environmental pollution. To mitigate these drawbacks, newly emerging technologies, such as enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE) have received huge interest from researchers around the world. Therefore, in this review, the most recent and emerging technologies are discussed for the extraction of marine phenolic compounds of interest for their antioxidant and other bioactivity in, e.g., cosmetic and food industry. Moreover, the opportunities and the bottleneck for upscaling of these technologies are also presented. 

    Author(s): Adane Tilahun Getachew, Charlotte Jacobsen, Susan Løvstad Holdt

  • Emersion Induces Nitrogen Release and Alteration of Nitrogen Metabolism in the Intertidal Genus Porphyra

    We investigated emersion-induced nitrogen (N) release from Porphyra umbilicalis Kütz. Thallus N concentration decreased during 4 h of emersion. Tissue N and soluble protein contents of P. umbilicalis were positively correlated and decreased during emersion. Growth of P. umbilicalis did not simply dilute the pre-emersion tissue N concentration. Rather, N was lost from tissues during emersion. We hypothesize that emersion-induced N release occurs when proteins are catabolized. While the δ15N value of tissues exposed to emersion was higher than that of continuously submerged tissues, further discrimination of stable N isotopes did not occur during the 4 h emersion. We conclude that N release from Porphyra during emersion did not result from bacterial denitrification, but possibly as a consequence of photorespiration. The release of N by P. umbilicalis into the environment during emersion suggests a novel role of intertidal seaweeds in the global N cycle. Emersion also altered the physiological function (nitrate uptake, nitrate reductase and glutamine synthetase activity, growth rate) of P. umbilicalis and the co-occurring upper intertidal species P. linearis Grev., though in a seasonally influenced manner. Individuals of the year round perennial species P. umbilicalis were more tolerant of emersion than ephemeral, cold temperate P. linearis in early winter. However, the mid-winter populations of both P. linearis and P. umbilicalis, had similar temporal physiological patterns during emersion.

    Author(s): Yarish, Charles Jang K. Kim, George P. Kraemer

  • Emission of atmospherically significant halocarbons by naturally occurring and farmed tropical macroalgae

    Current estimates of global halocarbon emissions highlight the tropical coastal environment as an important source of very short-lived (VSL) biogenic halocarbons to the troposphere and stratosphere, due to a combination of assumed high primary productivity in tropical coastal waters and the prevalence of deep convective transport, potentially capable of rapidly lifting surface emissions to the upper troposphere/lower stratosphere. However, despite this perceived importance, direct measurements of tropical coastal biogenic halocarbon emissions, notably from macroalgae (seaweeds), have not been made. In light of this, we provide the first dedicated study of halocarbon production by a range of 15 common tropical macroalgal species and compare these results to those from previous studies of polar and temperate macroalgae. Variation between species was substantial; CHBr3 production rates, measured at the end of a 24 h incubation, varied from 1.4 to 1129 pmol g FW−1 h−1 (FW = fresh weight of sample). We used our laboratory-determined emission rates to estimate emissions of CHBr3 and CH2Br2 (the two dominant VSL precursors of stratospheric bromine) from the coastlines of Malaysia and elsewhere in South East Asia (SEA). We compare these values to previous top-down model estimates of emissions from these regions and, by using several emission scenarios, we calculate an annual CHBr3 emission of 40 (6–224 Mmol Br−1 yr), a value that is lower than previous estimates. The contribution of tropical aquaculture to current emission budgets is also considered. Whilst the current aquaculture contribution to halocarbon emissions in this regional is small, the potential exists for substantial increases in aquaculture to make a significant contribution to regional halocarbon budgets.

    Author(s): E. C. Leedham , C. Hughes, F. S. L. Keng, S.-M. Phang, G. Malin, W. T. Sturges

  • Employment of polysaccharides in enzyme immobilization

    Analogous to free enzymes, immobilized enzymes are sturdy and resistant to environmental alterations. With unmatched high catalytic activity, turnover number, and selectivity, enzymes have the potential to utilize them as catalysts concerning practical applications which sometimes might get an obstacle due to the low thermal and chemical stability of enzymes. One of the best and out of numerous tested approaches, enzyme immobilization which makes use of varied enzyme-carrier interaction has made a remarkable dissimilarity. Another concerning concept, discussed here in this review, is the exploitation of polysaccharides which are carbohydrates made up of more than ten to thousands of monosaccharides linked through glycosidic bonds. Numerous natural poly- saccharides (cellulose, chitin, alginate, starch, carrageenan, pectin, etc.) base supports have been utilized in the recent past by amalgamating diverse immobilization techniques such as adsorption, covalent binding, entrap- ment, encapsulation, affinity immobilization, etc. The call for polysaccharides all over the globe has increased in the past few years due to their elevated usage in diverse sectors as a resource for green and sustainable materials. Additionally, such base supports are easily available, have an easy fabrication process, insolubility in an aqueous environment, are biocompatible, non-toxic, biodegradable, and physiologically inert. Undoubtedly, considering highly effective, economical, and skilled biotechnological processes, it is, nowadays, regarded as a promising approach for monitoring environmental conditions, textile-based industries, biotransformation, pharmaceutics, diagnostics, and food industries. This review gives an insight into a brief background of an enzyme, the merits of the enzyme immobilization approach, and why the concept of exploitation of polysaccharides with enzyme immobilization is grabbing a lot of attention from researchers nowadays. 

    Author(s): Archita Sharma, Karan Singh Thatai, Tanya Kuthiala, Gursharan Singh, Shailendra Kumar Arya

  • Employment potential of fisherwomen in the collection and post harvest operations of seaweeds in India

    Seaweeds are the renewable marine resources and they form the primary raw material for the agar and algin industries. They are mostly exploited from the south east coast of Tamil Nadu from Mandapam to Kanyakumari, Gujarat Coast, Lakshadweep islands and the Andaman and Nicobar islands. Even though substantial resources are available in our coastal waters, it is neither harvested to its fullest extent nor much efforts have been put forth. Seaweed collection renders extensive employment to the coastal fisher folk. The estimation of seaweed resources indicate that only a negligible quantity is harvested.

    At present nearly 5000 women depend on the seaweed industries for their livelihood. If the available resources are harvested to its optimal level, it can provide employment to another 20,000 coastal fisher folk in harvesting sector and an equal number in post harvest activities. Since the domain of seaweed collecting industry is mainly dominated by women, special efforts should be taken for its optimum exploitation and market expansion through diversified product development and their popularization. This paper deals with the employment potential offisherwomen in seaweed industries, problems and prospects in the collection and processing segments of seaweeds.

    Author(s): Immanuel, Sheela, Sathiadhas, R

  • Empowering blue economy: From underrated ecosystem to sustainable industry

    With increasing demand for resources to achieve global food-water-energy nexus and rapid decline in land-based sources, oceans represent both solution and boost to sustainable environment and economy. In addition to fundamental part of earth’s ecosystem for uncatalogued diversity of life, oceans are undervalued economy powerhouse with gross marine product value. With sustainable management of existing assets including ship- ping, transportation, manufacturing, fisheries, tourism and exploration of new business like marine biotech- nology and renewable energy, the ocean or blue economy has potential to fulfill sustainable development goals (SDG). In spite of recognition of blue economy as a new economic frontier, investments by existing industries and emergence of new ones are limited and less known, hence require more in depth attention and scientific un- derstanding. In the present study, authors present a systematic comparative assessment of blue economy sectors with distinct challenges and strategies to be further explored and implemented for industrial deployment. The conceptualization of integrated routes of bio(economy) by the current study can act as gateway for key stake- holders, i.e. governance, bluepreneurs (scientists and industries) to prioritize technologies for sustainable ap- plications of marine resources. 

    Author(s): Poonam Choudhary , Venkata Subhash G, Monika Khade, Sandip Savant, Amar Musale, Raja Krishna Kumar G, Meenakshi Sundaram Chelliah, Santanu Dasgupta

  • Endemic Pyropia species (Bangiales, Rhodophyta) from the Gulf of California, Mexico

    The evaluation of geographic distribution of Pyropia along the Gulf of California, Mexico, was realized using molecular data from two loci, the plastid rbcL gene and the partial 18S ribosomal DNA (rDNA), in conjunction with morphological observations. Dawson described two endemic species for the genus Pyropia (Pyropia hollenbergii and Pyropia pendula) in the Gulf of California based on taxonomic characteristics. In this study, we collected 130 samples from 13 locations from February 1998 to April 2008. Samples showed similar morphologies and growth habits and share a very similar type descriptions and habitat records. Using morphological and anatomical characteristics, we identify individuals as P. hollenbergii and P. pendula. However, using the molecular data, we identified five identities, which we have classified as P. hollenbergii, P. pendula, Pyropia sp. Gulf of California I (GCI), Pyropia sp. GCII, and Pyropia sp. GCIII. Phylogenetic trees based on partial 18S rDNA and rbcL sequence data showed a deep division in the genus that is not obviously correlated with existing morphological characteristics and indicate that representatives of the Gulf of California flora have undergone long reproductive isolation.

    Author(s): Yarish, Charles Isaí Pacheco-Ruíz, Rafael Riosmena-Rodríguez, Raquel Muñiz-Salazar, Juan Manuel López-Vivas

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