Digital library

  • Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.

    Author(s): Mark L. Wells , Philippe Potin, James S. Craigie, John A. Raven, Sabeeha S. Merchant, Katherine E. Helliwell, Alison G. Smith, Mary Ellen Camire, Susan H. Brawley
  • The current review explores the potential application of algal biomass for the production of biofuels and bio-based products. The variety of processes and pathways through which bio-valorization of algal biomass can be performed are described in this review. Various lipid extraction techniques from algal biomass along with transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products are reviewed in detail. The biorefinery model and its collaborative approach with various processes are highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products. The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their own perspective regarding the processes involved in production and the feasibility to make algal research a reality for the production of biofuels and bio-based products in a sustainable manner.

    Author(s): Manish Kumar , Yuqing Sun, Rashmi Rathour, Ashok Pandey, Indu Shekhar Thakur, Daniel C.W. Tsang
  • A growing world population is causing hazardous compounds to form at an increasingly rapid rate, calling for ecological action. Wastewater management and treatment is an expensive process that requires appropriate integration technology to make it more feasible and cost-effective. Algae are of great interest as potential feedstocks for various applications, including environmental sustainability, biofuel production, and the manufacture of high-value bioproducts. Bioremediation with microalgae is a potential approach to reduce wastewater pollution. The need for effective nutrient recovery, greenhouse gas reduction, wastewater treatment, and biomass reuse has led to a wide interest in the use of microalgae for wastewater treatment. Furthermore, algae biomass can be used to produce bioenergy and high-value bioproducts. The use of microalgae as medicine (production of bioactive and medicinal compounds), biofuels, biofertilizers, and food additives has been explored by researchers around the world. Technological and economic barriers currently prevent the commercial use of algae, and optimal downstream processes are needed to reduce production costs. Therefore, the simultaneous use of microalgae for wastewater treatment and biofuel production could be an economical approach to address these issues. This article provides an overview of algae and their application in bioremediation, bioenergy production, and bioactive compound production. It also highlights the current problems and opportunities in the algae-based sector, which has recently become quite promising.

    Author(s): Ashfaq Ahmad, Fawzi Banat, Habiba Alsafar, Shadi W. Hasan
  • A PDF Power Point of "Algae Co-Products as Potential Alternative Ingredients for Sea Urchins".

    Author(s): Addison L. Lawrence, Stephen A. Watts, John M. Lawrence
  • In development since 1996, AlgaeBase (http://www.algaebase.org) is an on-line database providing free access to authoritative taxonomic, distributional and nomenclatural information of more than 135,000 names of species and infraspecific taxa of algae set in the context of a taxonomic hierarchy. The project was initially funded by the Higher Education Authority, Department of Education and Science (Ireland) and the European Union (the SeaweedAfrica Project), and more recently by an industry sponsor in Ireland (Ocean Harvest Technology) and various phycological societies and organisations. The database currently includes more than 50,000 bibliographic references and incorporates the entire contents of the main phycological journals in addition to taxonomic, ecological, physiological and biochemical references in current and classical works. Nearly 10,000 PDFs are included, many of them of 19th-century taxonomic works that are rare and difficult to obtain. The data are searchable at all taxonomic levels from kingdom to species (and infraspecific names), and AlgaeBase strives to provide citations of the original publications of all taxa. For any of the 145,000 taxa (names of genera and above included), all subordinate taxa at the next lowest rank are indicated along with the number of species for each. Within each genus the species and infraspecies taxa are listed along with the current taxonomic status of each name. Nearly 17,000 images are provided for downloading and use in teaching or research, with copyright and other rights being retained by the original contributors or by AlgaeBase. This database is being used by 2,000-3,000 individual visitors each day with nearly 100,000 requests a day and receives over 7 million “hits” each year, increasing at about 20% per annum. A brief description of other main on-line algal resources such as Index Nominum Algarum, the Catalogue of Diatoms Names, CyanoDB, and AlgaTerra is provided.

    Author(s): Michael D. GUIRY, Gwendoline M. GUIRY, Liam MORRISON, Fabio RINDI, Salvador VALENZUELA MIRANDA, Arthur C. MATHIESON, Bruce C. PARKER, Anders LANGANGEN, David M. JOHN, Ignacio BÁRBARA, Christopher F. CARTERi, Pier KUIPERS, David J. GARBARY
  • Land-based aquaculture produces suspended solids in culture pond and settlement pond waters that could be harvested as a bioresource. Suspended solids were quantified, characterised and harvested from these two sources to assess their suitability for conversion to bioproducts. The suspended solids of settlement ponds were less concentrated (87.6±24.7mgL(-1)) than those of culture ponds (131.8±8.8mgL(-1)), but had a higher concentration of microalgae (27.5±4.0%) and consequently higher particulate organic carbon (24.8±4.7%) and particulate nitrogen (4.0±0.8%). The microalgal community also differed between sources with a higher concentration of fatty acids in the biomass from settlement ponds. Consequently, biochar produced from biomass harvested from settlement ponds was higher in organic carbon and nitrogen, with a lower cation exchange capacity. In conclusion, we characterised a renewable and potentially valuable bioresource for algal bioproducts derived from suspended solids in intensive land-based aquaculture.

    Author(s): Sarah A. Castine, Nicholas A. Paul, Marie Magnusson, Michael I. Bird, Rocky de Nys
  • In recent years, ever-increasing socio-economic awareness, and negative impact of excessive petro consumption have redirected the research interests towards bio-resources such as algal-based biomass. In order to meet current bio-economy challenges to produce high-value multiple products at a time, new integrated processes in research and development are necessary. Though various strategies have been posited for conversion of algal- based biomass to fuel and fine chemicals, none of them has been proved as economically viable and energetically feasible. Therefore, a range of other bio-products needs to be pursued. In this context, the algal bio-refinery concept has appeared with notable solution to recover multiple products from a single operation process. Herein, an algal-based bio-refinery platform for fuel, food, and pharmaceuticals considering Bio-refinery Complexity Index (BCI) has been evaluated, as an indicator of techno-economic risks. This review presents recent devel- opments on algal-biomass utilization for various value-added products as part of an integrated bio-refinery.

    Author(s): Rashmi Chandra, Hafiz M.N. Iqbal, Garima Vishal, Hyung-Sool Lee, Sunil Nagra
  • The optimised reduction of dissolved nutrient loads in aquaculture effluents through bioremediation requires selection of appropriate algal species and strains. The objective of the current study was to identify target species and strains from the macroalgal genus Ulva for bioremediation of land-based aquaculture facilities in Eastern Australia. We surveyed land-based aquaculture facilities and natural coastal environments across three geographic locations in Eastern Australia to determine which species of Ulva occur naturally in this region and conducted growth trials at three temperature treatments on a subset of samples from each location to determine whether local strains had superior performance under local environmental conditions. DNA barcoding using the markers ITS and tufA identified six species of Ulva, with U. ohnoi being the most common blade species and U. sp. 3 the most common filamentous species. Both species occurred at multiple land- based aquaculture facilities in Townsville and Brisbane and multiple strains of each species grew well in culture. Specific growth rates of U. ohnoi and U. sp. 3 were high (over 9% and 15% day21 respectively) across temperature treatments. Within species, strains of U. ohnoi had higher growth in temperatures corresponding to local conditions, suggesting that strains may be locally adapted. However, across all temperature treatments Townsville strains had the highest growth rates (11.2– 20.4% day21) and Sydney strains had the lowest growth rates (2.5–8.3% day21). We also found significant differences in growth between strains of U. ohnoi collected from the same geographic location, highlighting the potential to isolate and cultivate fast growing strains. In contrast, there was no clearly identifiable competitive strain of filamentous Ulva, with multiple species and strains having variable performance. The fast growth rates and broad geographical distribution of U. ohnoi make this an ideal species to target for bioremediation activities at land-based aquaculture facilities in Eastern Australia.

    Author(s): Rebecca J. Lawton, Leonardo Mata, Rocky de Nys, Nicholas A. Paul
  • The word weed, which carries often a derogative sense, means an economically useless plant (now animal too!) growing wild at the expense or to the detriment of a useful one that is or has been under cultivation. In this sense, the weed is worth only to be weeded out.

    Author(s): CMFRI, Kochi
  • Background: Azoxymethane (AOM) is a potent carcinogenic agent commonly used to induce colon cancer in rats; the cytotoxicity of AOM is considered to mediate oxidative stress. This study investigated the chemopreventive effect of three natural extracts [pomegranate peel extract (PomPE), papaya peel extract (PapPE) and seaweed extract (SE)] against AOM-induced oxidative stress and carcinogenesis in rat colon.

    Methods: Eighty Sprague-Dawley rats (aged 4 weeks) were randomly divided into 8 groups (10 rats/group). Control group was fed a basal diet; AOM-treated group was fed a basal diet and received AOM intraperitonial injections for two weeks at a dose of 15 mg/kg bodyweight, whereas the other six groups were received oral supplementation of PomPE, PapPE or SE, in the presence or absence of AOM injection. All animals were continuously fed ad-libitum until aged 16 weeks, then all rats were sacrificed and the colon tissues were examined microscopically for pathological changes and aberrant crypt foci (ACF) development, genotoxicity (induced micronuclei (MN) cells enumeration), and glutathione and lipid peroxidation.

    Results: Our results showed that AOM-induced ACF development and pathological changes in the colonic mucosal tissues, increased bone marrow MN cells and oxidative stress (glutathione depletion, lipid peroxidation) in rat colonic cells. The concomitant treatment of AOM with PomPE, PapPE or SE significantly ameliorated the cytotoxic effects of AOM.

    Conclusions: The results of this study provide in-vivo evidence that PomPE, PapPE and SE reduced the AOM-induced colon cancer in rats, through their potent anti-oxidant activities.

    Author(s): Mohammad S Rahman, Ahmed Al-Alawi, Sardar A Farooq, Halima K Al-Issaei, Mohamed A Al-Kindi, Marwa Al Riyami, Amani S Al-Rawahi, Mostafa I Waly

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