The world diet in 2062 or 2112 will be as unfamiliar to most people today as our own cosmopolitan diet of fast food and ethnic cuisines would be to our great grandparents in 1912. The new foods will be the result of fierce demand and resource pressures on food worldwide, astonishing new technologies, and emerging trends in diet, farming, healthcare and sustainability.
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Conventional off-shore and on-shore cultivation methods for marine macroalgae are both inadequate to pitch macroalgae as scalable renewable feedstock that can be grown across all coastal locations. With on-shore cultivation likely to be sustainable and preferred over eco-damaging open seas cultivation, new reactor systems need to be developed for on-shore cultivation of seaweeds at scale. The present work is an attempt to use the indigenously designed vertical multi-tubular air-lift photobioreactor system to grow Ulva lactuca through the entire year under natural conditions. Optimized operation of the 1000 L photobioreactor assembly demonstrated a year-round averaged productivity of 0.87 kg m−2.d−1 (fresh weight) implying 1800 ton.ha−1.y−1 feedstock production. Carbon dioxide supplementation (5%), optimized circulation velocity (0.25–0.35 m/s), and managing nitrogen supply (17 ppm), under natural light intensities (500–1400 μmol m−2.s−1) provided a year-round sustained and continuous production of Ulva lactuca biomass. The photobioreactor system designed as a modular, linearly scalable, and resilient system operates with low land and water footprints, and gives a multi-fold increase in renewable feedstock production compared to the conventional sea-based and other on-shore tank-based practices.
For the video summary of this article, see the file in the supplemental data.
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Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated l-fucose. Heterofucan SF-1.5v was extracted from the brown seaweed Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. This fucan showed antiproliferative activity on Hela cells and induced apoptosis. However, SF-1.5v was not able to activate caspases. Moreover, SF-1.5v induced glycogen synthase kinase (GSK) activation, but this protein is not involved in the heterofucan SF-1.5v induced apoptosis mechanism. In addition, ERK, p38, p53, pAKT and NFκB were not affected by the presence of SF-1.5v. We determined that SF-1.5v induces apoptosis in HeLa mainly by mitochondrial release of apoptosis-inducing factor (AIF) into cytosol. In addition, SF-1.5v decreases the expression of anti-apoptotic protein Bcl-2 and increased expression of apoptogenic protein Bax. These results are significant in that they provide a mechanistic framework for further exploring the use of SF-1.5v as a novel chemotherapeutics against human cervical cancer.
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In recent times, marine macroalgae (commonly known as seaweeds) drawing considerable attention globally as a renewable feed stock for various industrial applications. Commercial harvesting of seaweeds has reached new milestone with 27 million tones year-1 production (95% accounts to farming) with a market value of over US$ 4.8 billion (FAO, 2016). CSIR-Central Salt and Marine Chemicals Research Institute has been actively pursuing the seaweed research for nearly half a century. This institute takes pride in being first for pioneering seaweed cultivation, heralding an era of commercial seaweed farming in India. The production of Kappaphycus alvarezii has been substantially increased from 21 dry tonnes in 2001 to 1490 dry tonnes in 2013 with concomitant purchase value of < ₹ 4.5 to 35 ₹ kg−1 (dry). However, Indian seaweed industry is still depending on natural harvest for agrophytes specifically species of Gracilaria, Gelidium and Gelidiella. The continuous harvesting of natural stocks has been a growing concern for the long-term sustainability of the resource. In order to mitigate the over exploitation pressure on natural stocks, CSIR-CSMCRI developed sustainable cultivation methods of some of these species. Recently, Gracilaria dura from Indian waters has been reported to yield quality agarose as high as 20-25% on dry wt. basis with a gelling temperature 350C and gel strength of 1% gel > 1900 g. cm-2 this has attracted industrial attention. The fast expanding biotechnology and pharmaceutical sector in India is registering steady demand for agar, underpinning the need to initiate large scale farming of this alga. Thus successful aquaculture practise has been developed for ascertaining a continuous and reliable supply of quality raw material giving impetus to commercial operations especially in Gujarat coast – of which this alga is native. Among the hydrocolloids, agar is the second most prized product after agarose. According to a recent report, the wholesale price of agar has sharply increased to an all time high of USD 35-45 per kg due to scarcity of raw materials in response to resent regulations imposed by Moroccan government on natural harvest. The ongoing global supply chain crisis of agarophytes can be capitalized by India by spear heading the farming activity. This provides a scope and immense opportunity for India to emerge as a global producer as well as exporter of agarophytes. CSIR-CSMCRI in association with National Fisheries Development Board (NFDB), Hyderabad is trying to promote young fishermen as an entrepreneur from coastal villages across the country through successfully organizing trainings. The large-scale farming of this alga needs to be further strengthened and promoted by looking at potential socio-economic implication it offers for the inclusive economic growth in rural coastal settings. It would also help in the realization of the goal of doubling farmers' income by the year 2022. I sincerely believe that this manual will help new participants to practice seaweed cultivation more effectively. On behalf of CSIR and our Institute, I convey our best wishes for the successful implementation of the project.
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Seasonal aspects of growth. reproduction and spore output in G. pusillum growing (Sept. I 976-Feb. 1979) at Visakhapatnam coast were described. Plants occurred throughout the year with maximum growth in Sept. and Oct. and minimum between Jan. and April. Tetrasporophytes were predominant over the cystocarpic plants and seasonality was not observed in the abundance of these fruiting plants. Under laboratory conditions tetraspore and carpospore shedding was maximum on the 1st d and spore output gradually decreased from 2nd d onwards. Seasonal variations were not observed in the formation of sori and discharge of spores.
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Observations made for one year on the seasonal changes in growth, reproduction and spore output of Gracilaria foliifem and Gracilariopsis sjoestedtii are given. These red algae occurred only a few months during the year in the area of study. Maximum growth of G. foliifera was during April and of G. sjoestedtii was during September and January-March. Tetrasporophytes were more abundant than carposporophytes in G. foliifera, whereas in G. sjoestedtii carposporophytes occurred more. Maximum outputs of tetraspores and carpospores were recorded on the tirst day, and the period of peak shedding of spores coincided with the peak growth period of these seaweeds. There was, however, no definite rhythm of diurnal spore output.
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To examine the effects of two endophytic algae, Mikrosyphar zosterae (brown alga) and Ulvella ramosa (green alga), on the host Chondrus ocellatus (red alga), culture experiments were conducted. Four treatments were made: endophytefree (Chondrus only), endophyte-M (Chondrus + Mikrosyphar), endophyte-U (Chondrus + Ulvella), and endophytes-M·U (Chondrus + Mikrosyphar + Ulvella). After 3 weeks, the relative growth rates (RGRs) of frond lengths and the number of newly formed bladelets were examined. M. zosterae formed wart-like dots on C. ocellatus fronds, whereas U. ramosa made dark spots. The RGRs of frond lengths of C. ocellatus were significantly greater in the endophyte-free and endophyte-M treatment groups than in the endophyte-U and endophytes-M·U treatment groups, indicating that the growth of host C.ocellatus was inhibited more by the green endophyte U. ramosa than the brown endophyte M. zosterae. The number of newly produced bladelets was greater in the endophyte-U and endophytes-M·U groups than in the endophyte-free and endophyte-M treatment groups. These results indicate that the two endophytes inhibit growth of the host C. ocellatus. The negative effects of U. ramosa on C. ocellatus growth were more severe than those caused by M. zosterae. Furthermore, U. ramosa destroyed the apical meristems of C. ocellatus, whereas M. zosterae did not. On the other hand, C. ocellatus showed compensatory growth in the form of lateral branch production as U. ramosa attacked its apical meristems.
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Palmaria palmata was integrated with Atlantic halibut Hippoglossus hippoglossus on a commercial farm for one year starting in November, with a temperature range of 0.4 to 19.1°C. The seaweed was grown in nine plastic mesh cages (each 1.25 m3 volume) suspended in a concrete sump tank (46 m3) in each of three recirculating systems. Two tanks received effluent water from tanks stocked with halibut, and the third received ambient seawater serving as a control. Thalli were tumbled by continuous aeration, and held under a constant photoperiod of 16 : 8 (L : D). Palmaria stocking density was 2.95 kg m-3 initially, increasing to 9.85 kg m-3 after a year. Specific growth rate was highest from April to June (8.0 to 9.0°C),1.1% d-1 in the halibut effluent and 0.8% d-1 in the control, but declined to zero or less than zero above 14°C. Total tissue nitrogen of Palmaria in effluent water was 4.2 to 4.4% DW from January to October, whereas tissue N in the control system declined to 3.0-3.6% DW from April to October. Tissue carbon was independent of seawater source at 39.9% DW. Estimated tank space required by Palmaria for 50% removal of the nitrogen excreted by 100 t of halibut during winter is about 29,000 to 38,000 m2, ten times the area required for halibut culture. Fifty percent removal of carbon from the same system requires 7,200 to 9,800 m2 cultivation area. Integration of P. palmata with Atlantic halibut is feasible below 10°C, but is impractical during summer months due to disintegration of thalli associated with reproductive maturation.
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Marine biorefineries, based on macroalgal (seaweed) feedstocks, could provide sustainable alternative sources of food, energy, and materials. Green macroalgae, with their unique chemical composition, can contribute to marine biorefinery systems associated with a wide range of potential products. This review discusses the challenge of developing industrially relevant and environmentally-friendly green seaweed biorefineries. First, we review potential products from green seaweeds and their co-production, the key element in an integrated biorefinery. Second, we discuss large-scale cultivation, hydrothermal treatments, fermentation, anaerobic digestion, and emerging green solvents, pulsed electric field, microwave, and ultrasound processing technologies. Finally, we analyse the main polysaccharides in green seaweeds: sulfated polysaccharides, starch, and cellulose, as products of a cascading biorefinery, with emphasis on applications and technological challenges. We provide a comprehensive state-of-the-art review of green seaweed as feedstock for the biorefinery, analysing opportunities and challenges in the field.
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The rapidly increasing interest in utilizing seaweeds as sustainable raw material from which multiple high-value bioactive compounds can be recovered, has necessitated the development of new processing methods to achieve this. Brown seaweeds contain a range of bioactive compounds that are of commercial interest, including hydrocolloid and non-hydrocolloid polysaccharides, antioxidant polyphenols and unique pigments. Traditional polysaccharide extraction from brown seaweeds has relied on methods that require harsh chemical processing and sometimes also large amounts of energy and organic solvents. Commercial operation requires high recovery of the targeted compounds on the one hand, but simultaneously also the preservation of biological activity of the products on the other, an objective that is difficult to achieve using conventional methods. In order to address this shortcoming and to move toward more environmentally friendly processing in general, several greener extraction methods are being developed which have lower environmental footprint and sometimes also greater process efficiency, including enzymatic, sub and supercritical fluid, ultrasonic and microwave extraction techniques. This chapter explores these extraction techniques within the context of particularly brown seaweeds and provides an overview of potential advantages compared to conventional technologies. The work further elucidates how certain physiological characteristics of brown seaweeds can impact the processing thereof and looks toward possible future developments within the field of brown seaweed processing.
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