Optimization of culture conditions for the direct regeneration of Kappaphycus alvarezii (Rhodophyta,Solieriaceae)

Cultivation of seaweeds on a commercial scale requires a large number of propagules with desirable phenotypic traits which include high growth rates and resistance to diseases. Seaweed micropropagation can be considered as one of the best methods to provide a large amount of seedlings for commercial cultivation. This study was carried out to optimize the parameters known to affect the growth of Kappaphycus alvarezii in vitro and subsequently improve the production of seedlings through micropropagation. Suitability of media, concentration of phytoregulators, types and concentration of fertilizers, culture density, light intensity, interval of aeration activity, salinity, and pH were found to be critical factors for the growth of K. alvarezii. The optimum condition for direct regeneration of K. alvarezii in a culture vessel was found to be cultivation of explants in Provasoli's enriched seawater (PES) media supplemented with 2.5 mg L^?1 6-benzylaminopurine (BAP), 1.0 mg L^?1 indole-3-acetic acid (IAA), and 3.0 mg L^?1 natural seaweed extract (NSE) with culture density of 0.4 %?w/v, under light intensity of 75 μmol photons m^?2 s^?1, continuous aeration of 30.0 L h^?1, salinity of 30.0 ppt, and pH 7.5. An airlift photobioreactor was constructed for the mass propagation of K. alvarezii explants with optimum culture conditions obtained from the study. The optimum growth rates of the K. alvarezii explants in culture vessels (5.5 % day^?1) and photobioreactor (6.5 % day^?1) were found to be higher than the growth rate observed in field trials in the open sea (3.5 % day^?1). The information compiled during the course of this study will be of utility to commercial seaweed cultivators.     

Artificial Seed Production and Cultivation of the Edible Brown Alga, Sargassum Fulvellum (Turner) C. Agardh: Developing a new Species for Seaweed Cultivation in Korea

Sargassum fulvellum is a brown alga recently introduced to the seaweed cultivation industry in Korea. There is current interest in the commercial scale of aquaculture of this species. For the artificial seeding and cultivation of this alga, growth and maturation were investigated from September 2002 to August 2003. Indoor culture experiments for maturation induction were also conducted at temperatures of 5, 10, 15, 20 and 25 ^∘C and irradiances of 20, 50, 80 and 100 μmol photons m⁻² s⁻¹ under 16:8 h (L:D) photoperiod. Within a given culture test range, higher temperature and irradiance levels favoured the maturation of receptacles in S. fulvellum. Using temperature and irradiance control for thalli, artificial seed production of this species could be done one month earlier than thalli matured in nature. Under natural condition, receptacle formation of the plants began in February, and the eggs were released from March to April. For mature thalli of 200 g wet wt., artificial seeding was complete enough for attachment on seed strings of 100 m. Mean production obtained from the artificial seeding technique in situ was 3.0 kg wet wt m⁻¹ of culture rope during the cultivation period.     

Compensatory abilities depending on seasonal timing of thallus excision of the kelp Undaria pinnatifida cultivated in Matsushima Bay, northern Japan

Improved cultivation technology for the kelp Undaria pinnatifida is greatly needed to increase production to meet increasing commercial demand. A previous cultivation trial indicated that the crop yield of U. pinnatifida sporophytes could be increased greatly by thallus excision in late February due to compensatory growth of the remaining tissues. To develop this potential new cultivation technology, it is essential to identify the time period during which this kelp can compensate and its physiological responses to thallus excision. In this study, U. pinnatifida sporophytes were excised at about 30 cm above the meristem at the beginning of January, February, March, and April, respectively. Morphological features, photosynthesis, nutrient uptake, and carbon and nitrogen contents of excised kelps were measured and compared with these parameters in control kelps grown without excision. Both experimental and control kelps were farmed together in Matsushima Bay, northern Japan. The kelps excised in January and February showed significant increases in the lengths and dry weights of the blade, photosynthetic rates, nutrient uptake rates, and carbon and nitrogen contents compared with the control kelps, and the growth phase was prolonged for at least 1 month. No significant increases were found in dry weights and carbon and nitrogen contents of sporophylls until early April, which indicated that the maturation period was delayed. At the end of this experiment, the nitrogen contents of sporophyll tissues formed after excisions were significantly lower than those of tissues formed before excisions. In contrast, the kelps excised in March and April showed no significant increases in morphological and physiological parameters compared with control kelps. These results suggest that U. pinnatifida sporophytes exhibited great compensation when excisions were conducted during the growing phase in January and February but not in March and April when the maturation phase had started. The regulation of resource allocation to growth and maturation after thallus excisions in January and February likely results in prolongation of the growth phase and maturation phase in excised kelps.     

Effect of the commercial extract of the brown alga Ascophyllum nodosum Mont. on Kappaphycus alvarezii (Doty) Doty ex P.C. Silva in situ submitted to lethal temperatures

Kappaphycus alvarezii is being introduced in several countries and in some of them there is a need to adapt this cultivation to periods with lethal temperatures, such as the 16–18 °C that occurs in the winter in southern Brazil. Moreover, there is the need to maintain the seedlings during this lethal temperature period. Considering the promising results obtained with the commercial powder extract of Ascophyllum nodosum (Acadian marine plant extract powder—AMPEP) treatment in the cultivation of K. alvarezii in vitro and in the sea allowing more resistance to epiphytes and increasing the growth rate and carrageenan yield, it was hypothesized that seedlings previously subjected to an AMPEP treatment could be more resilient to lethal temperatures. The daily growth rate and carrageenan yield and gel quality (gel strength and gel viscosity) of K. alvarezii in vitro previously treated with AMPEP were analyzed under temperature stress. The daily growth rates and the gel strengths of the AMPEP-treated samples were increased. In spite of the lower carrageenan yield and lower gel viscosity, the values were within the ones accepted by the carrageenan industry. Thus, the treatment of the seedlings of the K. alvarezii with AMPEP solution can be used as an alternative to lower temperature effects on crops as a preventive action for the cultivation of the seedlings in tanks and in the sea in periods of low temperatures at sea.     

Ulva lactuca and U. flexuosa (Chlorophyta,Ulvophyceae) cultivation in Brazilian tropical waters: recruitment,growth, and ulvan yield

Ulva spp. are used in a wide range of commercial applications, including bioremediation, food, bioenergy, pharmaceuticals, and agriculture. The sulfated polysaccharide ulvan obtained from Ulva spp. is of interest for triggering plant defenses against disease. However, the cultivation of Ulva spp. is still in its infancy. This study verified the feasibility of cultivating Ulva lactuca and Ulva flexuosa at two sites on the tropical Brazilian coast. We investigated the following: (a) methods to induce sporulation, (b) comparison of seeding ropes inoculated in vitro versus seeding at sea over 40 days, (c) production and harvest cycles at 15 and 30 days, (d) growth productivity of U. flexuosa at sea and in outdoor tanks, and (e) comparison of ulvan yields from biomass cultivated in tanks and the sea. High nutrient treatment was the most efficient method to induce sporulation (7,540?±?3,133 spores m^?1). Sea-based cultivation of U. flexuosa was only successful at one site. Seeding of ropes in vitro was more efficient than seeding at sea (0.31?±?0.20 g m^?2 day^?1), and 15-day harvest cycles were most efficient (20.1?±?1.8 % day^?1; 0.46?±?0.11 g m^?2 day^?1). Despite differences in plant growth in tanks (27.9?±?4.4 % day^?1) and at sea (20.1?±?1.8 % day^?1), the dry biomass and ulvan yields (17.7?±?5.0 %) did not differ between these systems. Cultivation of U. flexuosa was feasible at sea using in vitro seeding with a production cycle of 15 days in Brazilian tropical waters and tanks with high irradiance and enriched seawater.     

Current status and future perspectives of Italian finfish aquaculture

Currently available data show that shellfish and finfish production in Italy, derived both from fisheries and aquaculture activities, is on the order of 474,000 tons, each activity representing 50 % of the total amount. In this context, the finfish aquaculture industry contributes on average 31 % to the national aquaculture production and on average 59 % of its value, giving a total amount of 72,000 tons and a value of around 351 million € (2010). According to FEAP statistics, Italy is the fourth largest finfish producer in EU27, after the UK, Greece, and Spain, while it is also one of the six largest finfish producers among the non-EU and EU member countries, together with Norway, UK, Greece, Turkey, and Spain. Presently, fish culture activities are mainly focused on rainbow trout (Oncorhynchus mykiss, 55.5 %), followed by European sea bass (Dicentrarchus labrax, 13.6 %), gilthead sea bream (Sparus aurata, 12.2 %), gray mullet (Mugil cephalus, 5.3 %), sturgeon (Acipenser spp., 2 %), and European eel (Anguilla anguilla, 1.7 %). Over the last 20 years, freshwater fish production and aquaculture (trout, carp, and eel) have decreased in Italy, with the exception of sturgeon. In contrast, marine fish production has significantly increased during the same period, and the two leading species, European sea bass and gilthead sea bream, presently contribute 25.8 % of the finfish production. From 1,900 tons in 1990, production reached 19,000 tons in 2010, with a 900 % increase, at an average percentage of 4.5 %. In addition, new marine fish species were successfully cultured over the same period. This review outlines the past and present situation of finfish culture in Italy and discusses future developments and priorities, with particular emphasis on new, emerging aquaculture species.     

Growth rate of the carrageenophyte Kappaphycus alvarezii (Rhodophyta, Gigartinales) introduced in subtropical waters of São Paulo State, Brazil

Twenty branches of Kappaphycus alvarezii (Doty) Doty ex P. Silva produced in unialgal culture and weighing about 3 g each were transferred into the sea monthly from October 1995 to October 1996 at Ubatuba Bay, São Paulo State, Brazil (23°26.9′S, 45°0.3′W), an area with mean monthly seawater temperature from 20.3 to 28.5°C (extremes: 17.0–31.0°C). All plants were harvested after the second month and a new series of growth experiments was performed using cuttings weighing from 100 to 150 g. The cultivation experiments were carried out using a floating system. Daily growth rates were calculated based on monthly weight measurements of each individual. Small branches produced in vitro showed high survival rates when introduced into the sea during all seasons. Growth rates observed for the transplanted branches during the first and second months in the sea were higher (6.5–10.7% day‐¹) than for subsequent cuttings produced in the sea (4.5–8.2% day‐¹). The latter values are in the range reported for other regions. Seasonal variation of growth rates was clearly related to seawater temperature. These results show that the commercial cultivation of K. alvarezii is technically feasible at Ubatuba Bay using a floating raft culture method.     

Empowerment of coastal communities in cultivation and processing of Kappaphycus alvarezii��a case study at Vizhinjam village, Kerala, India

The Science & Society Division of Department of Science & Technology, Government of India sanctioned a project in 2005 under the Woman Scientist Program (DST WOS-B) with an objective to develop technologies for the cultivation of high-value seaweeds widely used for industrial purposes/human consumption with empowerment of the coastal communities in Kerala. The project was divided into two phases: an experimental/investigational phase and an extension phase. In the experimental phase, pilot-scale culture experiments were conducted to evaluate the possibility and feasibility of the cultivation of the red alga, Kappaphycus alvarezii, in the southwest coast of Kerala. Pilot-scale studies of seaweed culture were conducted in the shallow subtidal waters on the Vizhinjam Harbor area in two bamboo rafts tied with seeds of K. alvarezii (100?±?1.20 g) following accepted culture and growth monitoring procedures. The first harvest was carried out after 45 days and the growth was nearly eight times the initial biomass (826?±?2.80 g). A group of local fishermen were trained in the fabrication of culture rafts, implanting seed material, rearing the seedlings with periodical monitoring, harvesting, and post-harvest technologies like drying, sorting, packing, etc. as part of the pilot-scale study. The pilot-scale efforts showed good scope for the further expansion of the large-scale cultivation of K. alvarezii in the southwest coast of Kerala by imparting training and adopting fishermen families for their additional employment/alternative livelihood. Success in the pilot-scale cultivation led to the second phase of the project, the extension phase, which fulfilled the main objectives of the DST WOS-B programme. Vizhinjam Gramapanchayat (village), where the pilot-scale cultivation was carried out successfully and headed by a woman president, came forward to pool resources of the project to be implemented as a Model Seaweed Cultivation Programme. A training/workshop on ??seaweed farming technology?? was conducted and nearly 60 people were trained. Mangalam purusha sahaya sangham, a registered self-help group (SHG) of Vizhinjam, came forward to start the culture operations at Vizhinjam with technical backup from the DST-WOS-B Programme. Some seaweed entrepreneurs from inside and outside Kerala also came forward with a 100% buyback guarantee for the produce. Nationalised banks like the State Bank of India offered loans to trained SHGs for starting seaweed cultivation at commercial scale.     

Effects of deep seawater medium on growth and amino acid profile of a sterile Ulva pertusa Kjellman (Ulvaceae, Chlorophyta)

The potential use of deep seawater (DSW) for the cultivation of macroalgae was evaluated by analysis of the growth rate of thalli (by surface area), photosynthetic pigment content, and total free amino acid content of sterile Ulva pertusa cultured in the control medium (one-fifth strength Provasoli’s enriched seawater (PES) medium), surface seawater (SSW) medium and also seawater medium collected from 400 m depth (400-DSW) and 1,200 m depth (1,200-DSW). The growth rate of the sterile U. pertusa grown in 400-DSW and 1,200-DSW was similar to that of thalli cultured in the one-fifth strength PES medium that had previously been shown to be the optimum concentration for the cultivation of Ulva. Photosynthetic pigment content in the control medium, 400-DSW- and 1,200-DSW-cultured thalli was 1.7–2.0 times higher than that of the SSW-cultured thalli. The total free amino acids content of the control medium and SSW-cultivated thalli was 264?±?64 and 120?±?39 mg per 100 g dry weight, whereas the 400-DSW- and 1,200-DSW-cultivated thalli had significantly more amino acids (342?±?69–327?±?64 mg per 100 g dry weight). The results of this study indicate that DSW has a high potential for cultivation of edible macroalgae without any supply of extra nutrient until it grows to harvest size.     

Isolation of potential fungal pathogens in gorgonian corals at the Tropical Eastern Pacific

A major environmental problem in the ocean is the alarming increase in diseases affecting diverse marine organisms including corals. Environmental factors such as the rising seawater temperatures and terrestrial microbial input to the ocean have contributed to the increase in diseased organisms. We isolated and identified the fungal agents that may be leading to a disease in the Pacific sea fan Pacifigorgia eximia (Gorgoniidae, Octocorallia) in the Tropical Eastern Pacific. We isolated thirteen fungal genera in healthy and diseased colonies including Aspergillus sydowii. Aspergillus has been previously identified as responsible for the mortality of gorgonian corals in the Caribbean. This disease was observed in the Eastern Pacific affecting a completely different set of species nearly 30 years after the Caribbean outbreak, which concur with rising seawater temperatures and thermal anomalies that have been observed in the last 4 years.     

Seasonal variation in growth and carrageenan yield in cultivated Kappaphycus alvarezii (Doty) Doty on the coastal waters of Ramanathapuram district,Tamil Nadu

Kappaphycus alvarezii, a kappa carrageenan yielding red seaweed, was cultivated in Indian subtropical waters on the Palk Bay side of Bay of Bengal in Ramanathapuram district, Tamil Nadu, at three different sites: Vedalai, Munaikadu, and Thonithurai, for 1 year from April 2011 to March 2012. The maximum crop yields of 416 ± 51 and 550 ± 41 FW raft^?1 were recorded at Vedalai and Munaikadu, respectively, in December 2011, whereas a maximum of 326 ± 49 FW raft^?1 was recorded at Thonithurai in April 2011. Similarly, the maximum daily growth rates (DGRs) of 4.30 ± 0.51 % and 4.92 ± 0.40 % were obtained at Vedalai and Munaikadu, respectively, in December 2011, and 3.76 ± 0.48 % was recorded at Thonithurai in April 2011. Variations in environmental parameters like seawater temperature, salinity, nitrate, and phosphate were found to influence the growth of the seaweed. The maximum carrageenan content as a percentage of dry weight was 29.30 ± 0.61 % (Vedalai), 31.00 ± 0.71 % (Munaikadu), and 29.10 ± 1.12 % (Thonithurai) in March 2012. The data on moisture content (%), clean anhydrous weed/salt ratio, and carrageenan yield obtained in this study fulfilled those of international standards. Further, the results indicated that large-scale cultivation by either NGOs or self-help groups (SHGs) may be taken up along the coastal waters for the benefit of the poverty-stricken coastal people as their livelihood, as the growth rate obtained in this study compared well with that recommended for commercial cultivation elsewhere.     

An 800 year record of mangrove dynamics and human activities in the upper Gulf of Thailand

A multiproxy record comprising pollen, charcoal, loss on ignition and particle size analyses from two radiocarbon dated sediment cores from Klong Kone subdistrict on the western coast of the Gulf of Thailand provides insights on mangrove dynamics, environmental changes and human activities during the last 800 years. The mangroves were dominated by Rhizophora which indicates that the area has been influenced by the sea level from at least 820 cal bp until 720 cal bp. An intertidal area may have formed that supported mangrove development as part of an old shoreline during 820–720 cal bp. After 720 cal bp, mangroves decreased and were replaced by grasses, suggesting that a lower sea level caused the mangroves to grow closer to the sea until around 140 cal bp. Cereal pollen increased from 720 cal bp suggesting probable use of the shoreline for intensive cultivation. The mangroves were characterised by Avicennia, which increased toward the top of the 2 cores, suggesting that the mangroves then grew further inland, probably due to recent sea-level rise. Intensive human activity is recorded during the 20th century, as indicated by increased particle size, charcoal and carbonate content. At present, human activity in the area includes dams and construction as well as aquaculture.     

Cultivation of a brown alga, <Emphasis Type="Italic">Undariopsis peterseniana</Emphasis> (Kjellman) Miyabe and Okamura,as a warm-temperature species by artificial seed production in Korea

Undariopsis peterseniana is an endangered annual brown alga in Udo, Jeju Island, Korea. There is current interest in the commercial-scale aquaculture of this species for warm-water species development in Korea. Growth and maturation were investigated from January to December 2007 in their natural habitat. Zoospores were transplanted into an intensive seaweed culture ground in Wando, southern coast of Korea, for the mass cultivation of this species. Indoor and outdoor cultivation were conducted from June 2007 to May 2008. Mean production obtained from the zoospore seeding was 31.1 ± 1.5 kg wet wt. m⁻¹ of culture rope during the cultivation period in situ. Transplanted F₁ thalli in Wando had a length 1.7 times longer than their parents in Udo, and their maximal growth period changed from June (at 19.9°C in Udo of natural habitat) to April (at 14.0°C in Wando of culture ground). The relationship between optimal water depth for culture and underwater irradiance during the U. peterseniana cultivation was defined as: y = - 0.78 ×+ 7.67( r² = 0.92 ) y = - 0.78 \times + 7.67\left( {{r^2} = 0.92} \right) . This study indicates that U. peterseniana could be successfully transferred to the northern coast beyond the original habitat in Jeju Island.     

Influence of germination date on Dioon edule (Zamiaceae) seedling tolerance to water stress

Dioon edule seedling mortality is mostly attributed to dehydration by prolonged drought, even when they present xeromorphic characteristics like the adult plants. The effect of germination date (GD) and soil water deficit on seedling tolerance to water stress was assessed. The seedlings germinated and grown from mature seeds every month from December to April GD were selected to evaluate the leaf area, photosynthetic pigment content, crassulacean acid metabolism (CAM) activity, stomatal conductance (gs) and leaflet anatomy at soil water potential (Ψs) of 0.0 MPa (day 1), ?0.1 MPa (day 40), ?1.0 MPa (day 90), ?1.5 MPa (day 130), and a control (0.0 MPa at day 130) to recognize differences due to leaf development. The seedlings shifted from C₃ to CAM cycling when exposed to water stress at Ψs of ?1.0 MPa, like adult plants. The March–April GD seedlings with undeveloped sclerified hypodermis and stomata, presented reduced leaf area, lower Chlorophyll a/b ratio, higher CAM activity and midday partial stomatal closure when reached Ψs of ?1.0 MPa. These have higher probability of dehydration during severe drought (February–April) than those of the December–February GD with similar Ψs. Plants used for restoration purposes must have full leaf development to increase the survival.     

The effect of gradual increase in salinity on the biomass productivity and biochemical composition of several marine,halotolerant<Emphasis Type="Bold">,</Emphasis> and halophilic microalgae

Open ponds are the preferred cultivation system for large-scale microalgal biomass production. To be more sustainable, commercial scale biomass production should rely on seawater, as freshwater is a limiting resource, especially in places with high irradiance. If seawater is used for both pond fill and evaporative volume makeup, salinity of the growth media will rise over time. It is not possible for any species to achieve optimum growth over the whole saline spectrum (from seawater salinity level up to salt saturation state). In this study, we investigated the effects of gradual salinity increase (between 35 and 233 ppt) on biomass productivity and biochemical composition (lipid and carbohydrate) of six marine, two halotolerant, and a halophilic microalgae. A gradual and slow stepped salinity increase was found to expand the salinity tolerance range of tested species. A gradual reduction in biomass productivity and maximum photochemical efficiency was observed as a consequence of increased salinity in all tested species. Among the marine microalgae, Tetraselmis showed highest biomass productivity (32 mg L^?1 day^?1) with widest salinity tolerance range (35 to 109 ppt). Halotolerant Amphora and Navicula were able to grow from 35 ppt to 129 ppt salinity. Halophilic Dunaliella was the only species capable of growing between 35 and 233 ppt and showed highest lipid content (56.2%) among all tested species. This study showed that it should be possible to maintain high biomass in open outdoor cultivation utilizing seawater by growing Tetraselmis, Amphora, and Dunaliella one after another as salinity increases in the cultivation system.     

Strain selection and initiation timing influence the cultivation period of <Emphasis Type="Italic">Saccharina japonica</Emphasis> and their impact on the abalone feed industry in Korea

Cultivations of the brown seaweed, Saccharina japonica, was developed, promoted, and industrialized in the 1970s and is highly valued in Korea both for human consumption and as a feed for the rapidly developing abalone farming industry. Production has continually increased, and approximately 442,637 tonnes wet weight was harvested in Korea in 2015. Abalone is a highly sought-after delicacy in Korea, and the abalone farming industry has been developed based on a stable production of seaweed. Korean abalone farmers prefer to feed their stock on locally cultured S. japonica; however, between August and November, the supply of farmed S. japonica declines because higher seawater temperatures reduce S. japonica productivity. In an attempt to overcome this temperature-induced period of low production, cultivation trials with a strain of S. japonica selected to withstand higher cultivation temperatures were undertaken. Strain selection involved using individual parent thalli that were found to remain productive under high seawater temperature (26 °C) at Wando. Male and female gametophytes were isolated through 3 cycles of free-living gametophyte culture to produce the F₃ strain used in the production trials. Production trials using the selected strain were initiated every month between December 2014 and March 2015. This delayed the initiation of culture beyond the latest initiation time currently used by farmers (December). Delaying initiation of cultivation resulted in delayed maximum growth compared to the control. Growth of the F₃ strain continued for up to 3 months longer than normally achieved on farms for non-selected thalli. The mean length, growth rate, and biomass were also greater than those achieved by the control strain. The use of the F₃ strain of S. japonica coupled with delayed initiation of culture can therefore be used to help to ensure a stable year round algal feed supply for abalone industry in Korea.     

Differential response of varying salinity and temperature on zoospore induction, regeneration and daily growth rate in Ulva fasciata (Chlorophyta, Ulvales)

Seaweed cultivation is imperative to augment increasing industrial demand. Ulva fasciata Delile is a potential seaweed for cultivation with applications in food industries. There is a renewed interest in large-scale aquaculture of this species in India due to its envisaged demand in snack food products. In the present study, we have successfully demonstrated the possibility of inducing zoospores in vegetative tissue, effective regeneration and improved growth in this seaweed by manipulating salinity (from 15 to 30 psu) and temperature (from 15 to 35°C). The optimum salinity and temperature requirement for zoospores induction were found to be 15 psu and 25°C, respectively. The quadriflagellate zoospores showed negative phototaxis and the settlement and germination pattern similar to several other green seaweeds. The optimum regeneration (78.53?±?10.05%) was recorded at 25°C and 30 psu salinity. The maximum daily growth rate (16.1?±?0.28%) was at 25°C and 30 psu salinity which corresponded to the field conditions. This method could be further refined at nursery culture to achieve artificial seeding essential for the success of commercial cultivation of this seaweed.     

Cost-effective IMTA: a comparison of the production efficiencies of mussels and seaweed

This paper compares the biofilter capacity and cost-effectiveness of blue mussels (Mytilus edulis) and seaweed for use in integrated multi-trophic aquaculture (IMTA) based on experiences in Ireland and Denmark. This comparison shows that weight for weight, mussels are a better biofilter than seaweed with regard to the amount of nitrogen assimilated. Furthermore, in optimized systems, areal requirement for mussels is similar to the cultivation of the same tonnage (1,000 t) of seaweed (approximately 8 ha). The cost-effectiveness of a mussel biofilter is €11–30 kg^?1 nitrogen (N) removed based on various examples compared to production costs of €209–672 removed and €1,013 kg^?1 N removed, respectively, for Laminaria digitata and Alaria esculenta from extrapolated laboratory and field trials. However, commercial seaweed (Saccharina latissima) producers claim that production costs are less than €10–38 kg^?1 N removed. These up-scaled and commercial figures make the seaweed cost competitive to mussels for removal of nitrogen. Disadvantages such as predators (e.g. eider ducks) and biofouling should also be taken into account before choice of biofilter is made. These drawbacks can reduce overall biofilter capacity and biomass value as a consequence of biomass spoilage or loss. However, disadvantages may be mitigated by seasonal choice of cultivation and harvest times. Cultivation technologies and harvesting methods may be improved together with breeding to improve the cost-efficiency of the biofilter, especially in the newer European seaweed cultivation. Furthermore, upscaling of IMTA to commercial proportions, other than the Danish example, would allow more real data on production costs and revenues.     

Production of Mycosporine-Like Amino Acids from <Emphasis Type="Italic">Gracilaria vermiculophylla</Emphasis> (Rhodophyta) Cultured Through One Year in an Integrated Multi-trophic Aquaculture (IMTA) System

This study evaluates the production of biomass and mycosporine-like amino acids (MAAs) throughout the year in Gracilaria vermiculophylla (Rhodophyta) collected in Ria de Aveiro (Portugal). The algae were grown in outdoor tanks in seawater with the addition of fishpond effluents under two different water flows (100 and 200 L h^?1) in an integrated multi-trophic aquaculture (IMTA) system (tanks 1200 L; 1.5 m²) and different algal densities (3, 5, and 7 kg m^?2). MAA content in IMTA seaweeds was significantly affected by the interaction of time and stocking density, but not by the water flow. The highest MAA content was observed in April (about 3.13 mg g^?1 DW) followed by May (1.79 mg g^?1 DW). Seaweed biomass productivity was higher in May (372.06 g DW m^?2 week^?1) than in April (353.40 g DW m^?2 week^?1). Four MAAs were identified by HPLC and electrospray ionization mass spectrometry (ESI-MS) in G. vermiculophylla: Porphyra-334, Shinorine, Palythine and Asterina-330. The highest levels of Porphyra-334 and Shinorine were reached from November to January and the Palythine + Asterina-330 from April to August. Taking into account the average biomass and MAA production of G. vermiculophylla growing in this IMTA system (8.56 g of MAA in 18 m² culture along 8 months; 35.5% produced in April), a total amount of 71.33 g MAA year^?1 could be produced in this system by scaling up to 100 m². MAAs could be further used as photoprotector and antioxidant compounds in cosmetic products.     

Production of flavonoids and polysaccharide by adding elicitor in different cellular cultivation processes of Glycyrrhiza uralensis Fisch

In this study, callus and cell suspension were induced from seedlings of licorice (G. uralensis). In addition, it was revealed that the appropriate concentration of sucrose could promote the callus growth and increase the content of polysaccharide. The methyl jasmonate (MJ) and phenylalanine (PHE) could enhance the callus growth and content of flavonoids for G. uralensis. For producing more flavonoids and polysaccharide, two-stage cultivation was performed. In the first step, 30 g L^?1 sucrose was fed into a 5-L balloon-type bubble bioreactor on 8th day of culture to enhance cell production and metabolite production. In a two-stage cultivation process, PHE (2 mM) and MJ (5 mg L^?1) were added into a 5-L balloon-type bubble bioreactor after 10 days of culture. Using a fed-batch cultivation strategy (30 g L^?1 sucrose was fed into a 5-L balloon-type bubble bioreactor on 8th day), polysaccharide production was enhanced to 1.19 g L^?1, which was 2.12-fold greater than that in batch cultivation. The flavonoids yield (55.42 mg L^?1) which was about 22 % higher than that in batch cultivation was obtained on 21st day. In a two-stage cultivation process, the polysaccharide content was increased by 1.14- and 2.12-fold compared with fed-batch cultivation and batch cultivation on 15th day. Meanwhile, total flavonoids yield (132.36 mg L^?1) on 15th day, was increased by 2.26- and 2.67-fold compared with fed-batch cultivation and batch cultivation. In conclusion, two-stage cultivation process combined with the sucrose and elicitor treatment could promote both the callus growth and the secondary metabolites accumulation.