Showing papers in "Journal of Applied Phycology in 2018"
TL;DR: This comprehensive review summarizes the most important and recent developments of microalgae use as supplement or feed additive to replace fishmeal and fish oil for use in aquaculture.
Abstract: Due to the rapid global expansion of the aquaculture industry, access to key feedstuffs (fishmeal and fish oil) is becoming increasingly limited because of the finite resources available for wild fish harvesting. This has resulted in other sources of feedstuffs being investigated, namely plant origin substitutes for fishmeal and fish oil for aquafeed. Conventional land-based crops have been favored for some applications as substitutes for a portion of the fishmeal, but they can result in changes in the nutritional quality of the fish produced. Microalgae can be regarded as a promising alternative that can replace fishmeal and fish oil and ensure sustainability standards in aquaculture. They have a potential for use in aquaculture as they are sources of protein, lipid, vitamins, minerals, pigments, etc. This comprehensive review summarizes the most important and recent developments of microalgae use as supplement or feed additive to replace fishmeal and fish oil for use in aquaculture. It also reflects the microalgal nutritional quality and digestibility of microalgae-based aquafeed. Simultaneously, safety and regulatory aspects of microalgae feed applications, major challenges on the use microalgae in aquafeed in commercial production, and future research and development perspective are also presented in a critical manner. This review will serve as a useful guide to present current status of knowledge and highlight key areas for future development of a microalgae-based aquafeed industry and overall development of a sustainable aquaculture industry.
261 citations
TL;DR: The potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress is shown and the possibility of their use as plant growth biostimulants under harsh environmental conditions is highlighted.
Abstract: Microalgal exopolysaccharides represent a potential sustainable alternative for the enhancement and protection of agricultural crops including management of both biotic and abiotic stress. In the present study, we investigated the potential of Dunaliella salina exopolysaccharides (PS) to attenuate the effect of salt stress on growth of Solanum lycopersicum, which was grown under different salinity levels (3 and 6 g L−1 NaCl). The effects of PS treatment on plant growth, osmoprotectant molecules, protein content, and antioxidant enzymes activities of tomato plants under salt stress were analyzed. A metabolomics study showed that the exopolysaccharides released by D. salina contained sulfated moiety along with carbohydrates and uronic acids. The application of sulfated exopolysaccharides on tomato plants alleviated the salt stress and mitigated the decrease in length and dry weight of the plant’s shoot and root systems, as well as that of potassium (K+), and K+/Na+ ratio. Furthermore, the increase in proline, phenolic compounds, Na+, and antioxidant enzymes (CAT, POD, SOD) activities caused by salt stress were attenuated after the exopolysaccharide treatment. GC-MS metabolomics analysis showed that PS treatment allowed the activation and/or inhibition of various metabolic pathways involved in the plant’s tolerance to stress such as jasmonic acid-dependent pathways. This study shows the potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress and highlights the possibility of their use as plant growth biostimulants under harsh environmental conditions.
97 citations
TL;DR: In this article, three different protein extraction methods were applied to three Swedish seaweeds (Porphyra umbilicalis, Ulva lactuca, and Saccharina latissima).
Abstract: The demand for vegetable proteins increases globally and seaweeds are considered novel and promising protein sources. However, the tough polysaccharide-rich cell walls and the abundance of polyphenols reduce the extractability and digestibility of seaweed proteins. Therefore, food grade, scalable, and environmentally friendly protein extraction techniques are required. To date, little work has been carried out on developing such methods taking into consideration the structural differences between seaweed species. In this work, three different protein extraction methods were applied to three Swedish seaweeds (Porphyra umbilicalis, Ulva lactuca, and Saccharina latissima). These methods included (I) a traditional method using sonication in water and subsequent ammonium sulfate-induced protein precipitation, (II) the pH-shift protein extraction method using alkaline protein solubilization followed by isoelectric precipitation, and (III) the accelerated solvent extraction (ASE®) method where proteins are extracted after pre-removal of lipids and phlorotannins. The highest protein yields were achieved using the pH-shift method applied to P. umbilicalis (22.6 ± 7.3%) and S. latissima (25.1 ± 0.9%). The traditional method resulted in the greatest protein yield when applied to U. lactuca (19.6 ± 0.8%). However, the protein concentration in the produced extracts was highest for all three species using the pH-shift method (71.0 ± 3.7%, 51.2 ± 2.1%, and 40.7 ± 0.5% for P. umbilicalis, U. lactuca, and S. latissima, respectively). In addition, the pH-shift method was found to concentrate the fatty acids in U. lactuca and S. latissima by 2.2 and 1.6 times, respectively. The pH-shift method can therefore be considered a promising strategy for producing seaweed protein ingredients for use in food and feed.
92 citations
TL;DR: In this article, the authors examined the sorption of fluorescent polystyrene (PS) microplastic particles to edible macroalga (seaweed) Fucus vesiculosus and investigated to what extent adsorbed PS particles could be washed off, using an industrial relevant method.
Abstract: Increased global demands for food have raised interest for seaweed as a healthy and sustainable food source. At the same time, the large amounts of microplastic in the oceans have raised concern in relation to pollution of seafood including sea vegetables. The aim of this study was to examine sorption of fluorescent polystyrene (PS) microplastic particles to edible macroalga (seaweed) Fucus vesiculosus, and to investigate to what extent adsorbed PS particles could be washed off, using an industrial relevant method. PS microplastic particles (diameter of 20 μm) were used in a concentration of 2.65 mg L−1 (corresponding to 597 particles per mL) in filtrated seawater (50 mL) to treat F. vesiculosus distal tips in blue cap flasks (100 mL) placed in a rotary box for 2 h. Results showed sorption of PS microplastic particles to F. vesiculosus analysed by microscopy and a significant reduction of 94.5% by washing. These results were based on high microplastic concentrations, not comparable to natural conditions/concentrations. Nonetheless, this study provides methodological and mechanistic insights into procedures for investigating the sorption of microplastics to seaweed, for which there is currently no established standardised method.
92 citations
TL;DR: In this article, the authors evaluated morphological and molecular responses induced by microalgae (Chlorella vulgaris and Scenedesmus quadricauda) extracts in Beta vulgaris L. seedlings.
Abstract: The characterization of nutrient and biostimulant effects in crops is complex and needs rigorous evaluations. In this study, we evaluated morphological and molecular responses induced by microalgae (Chlorella vulgaris and Scenedesmus quadricauda) extracts in Beta vulgaris L. The two microalgae extracts were firstly characterized by CNS, Fourier transform infrared spectroscopic analysis (FT-IR), and carbon-13 nuclear magnetic resonance (13C NMR). Seedlings were grown in Hoagland’s solution under controlled conditions. After 5 days of growth, 2 mL L−1 (1 mg Corg L−1) and 4 mL L−1 (2 mg Corg L−1) of the two microalgae extracts were added to the Hoagland solution. Roots were sampled 36 h after treatments. Inductively coupled plasma spectrometry (ICP-OES) and nanofluidic real-time PCR (OpenArray system) were used for sample profiling. Fifty-three sugar beet genes putatively involved in sulfate starvation were tested in treated and untreated samples. Root morphological traits were measured by means of a scanner-based image analysis system. Multivariate statistical analysis revealed no significant changes in the ionomic profile of Hoagland’s solutions treated with the two microalgae extracts with respect to that of the untreated solution. At the molecular level, microalgae extract supplies upregulated many of the evaluated genes. Functional categorization revealed these genes to be related to various biological pathways and processes including primary and secondary metabolism and intracellular transport. At the morphological level, the treated seedlings showed significantly higher values for root traits related to soil exploration and nutrient uptake, such as total root length, fine root length (diameter < 0.5 mm), and number of root tips, than the untreated plants. These data indicate that microalgae extracts have biostimulant effects on the expression of root traits and genes related to nutrient acquisition in sugar beet.
91 citations
TL;DR: The stress concept as it applies to algae, especially microalgae is reviewed and stress is defined as the disruption of homeostasis due to a stressor and the stress response represents the changes in cell metabolism during acclimation and the restoration ofHomeostasis.
Abstract: The term ‘stress’ is widely used in the algal literature, usually in the context of the response of algae to changed abiotic and biotic factors. ‘Stress’ is seen as the cause of changes in algal metabolism and composition and often as a factor inducing the overproduction of particular desirable secondary metabolites. However, ‘stress’ is used differently by different authors and is often ill-defined, with no clear separation of cause and effect. This lack of a defined stress concept leads to poor experimental design, miscommunication of results and potentially erroneous conclusions. This paper reviews the stress concept as it applies to algae, especially microalgae. Here, stress is defined as the disruption of homeostasis due to a stressor and the stress response represents the changes in cell metabolism during acclimation and the restoration of homeostasis. Once homeostasis is restored the cell is no longer stressed. The stages of the stress response, i.e. alarm, regulation, acclimation and adaptation, are described. The well-studied responses of the green halophilic alga Dunaliella to changes in salinity are used as an example to illustrate the stress response and acclimation to the changed salinity.
90 citations
TL;DR: The results of this assay show that foliar application of Scenedesmus accelerated plant development in terms of higher rates of root growth, leaf and shoot development, and earliness of flowering and that microalgae hydrolysate supply can improve the plant nutrient status.
Abstract: In horticultural practice accelerated plant development and particularly earlier flowering, has been reported with microalgae applications. Therefore, the objective of this work was to study the effects of foliar spraying with Scenedesmus sp. and Arthrospira platensis hydrolysates on Petunia x hybrida plant development and leaf nutrient status. Three treatments were tested: T1 (foliar application with water, the control), T2 (foliar application with Arthrospira), and T3 (foliar application with Scenedesmus). Foliar spraying was applied five times (0, 14, 28, 35, and 42 days after transplanting). The concentration of both microalgae was 10 g L−1. At the end of the trial biometric parameters and nutrient concentration in photosynthetic organs (the leaves) were measured. The results of this assay show that foliar application of Scenedesmus accelerated plant development in terms of higher rates of root growth, leaf and shoot development, and earliness of flowering. Arthrospira enhanced the root dry matter, the number of flowers per plant, and the water content. Nevertheless, a reduction was found in the conductive tissue (stem + petiole) dry weight with Arthrospira compared with Scenedesmus and the control. The results also show that microalgae hydrolysate supply can improve the plant nutrient status. Based on these results, it is advisable to use Scenedesmus hydrolysates in foliar applications to increase the blooming of Petunia x hybrida.
80 citations
TL;DR: Although Rygex and Super Fifty treatments did not significantly enhance plant growth and yield under salt treatment, they enhanced the accumulation of minerals, antioxidants, and essential amino acids in tomato fruits, with an overall improvement in nutritional value.
Abstract: Seaweed extracts (SWE) are widely used to improve plant growth, fruit quality, and stress tolerance. However, the functional link between the complex composition of algal-based products and their mechanisms of action has been only marginally addressed. A greenhouse experiment was performed on Microtom tomato plants in order to evaluate the effect of two Ascophyllum nodosum-based algal derivatives, Rygex (R) and Super Fifty (SF), on a tomato exposed to salinity (0, 42.5, and 85 mM NaCl) and normal and reduced nutrient availability (100 and 70% of the standard regimen). Bioactive compounds, with possible beneficial effects on growth and stress adaptation, were characterized via gas chromatography-mass spectrometry analysis (GC-MS). Enhanced growth of 13% was observed with Super Fifty treatment under a full-strength nutritional regimen, independent of the salinity treatment. Although Rygex and Super Fifty treatments did not significantly enhance plant growth and yield under salt treatment, they enhanced the accumulation of minerals, antioxidants, and essential amino acids in tomato fruits, with an overall improvement in nutritional value. Overall, SWE may affect and ameliorate different aspects of nutrition and stress tolerance and thus contribute to the sustainability of agricultural systems. Elucidating the link between bioactive compounds in SWE and plant responses will be critical to characterizing the mechanism of action of SWE.
71 citations
TL;DR: Chaetoceros sp.
Abstract: Cultivation temperature is one of the major factors affecting the growth and lipid accumulation of microalgae. In this study, the effects of temperature on the growth, lipid content, fatty acid composition and biodiesel properties of the marine microalgae Chaetoceros sp. FIKU035, Tetraselmis suecica FIKU032 and Nannochloropsis sp. FIKU036 were investigated. These species were cultured at different temperatures (25, 30, 35 and 40 °C). The results showed that the specific growth rate, biomass and lipid content of all microalgae decreased with increasing temperature. With regards to fatty acids, the presence of saturated fatty acids (SFAs) in T. suecica FIKU032 and Nannochloropsis sp. FIKU036 decreased with increasing temperature, in contrast with polyunsaturated fatty acids (PUFAs). Moreover, Chaetoceros sp. FIKU035 was the only species that could grow at 40 °C. The highest lipid productivity was observed in Chaetoceros sp. FIKU035 when cultivated at 25 °C (66.73 ± 1.34 mg L−1 day−1) and 30 °C (61.35 ± 2.89 mg L−1 day−1). Moreover, the biodiesel properties (cetane number, cold filter plugging point, kinematic viscosity and density) of the lipids obtained from this species were in accordance with biodiesel standards. This study indicated that Chaetoceros sp. FIKU035 can be considered as a suitable species for biodiesel production in outdoor cultivation.
68 citations
TL;DR: The present report integrates existing information on the red algae lectins, their carbohydrate specificity, and characteristics of purified lectins into their anti-viral activity against various enveloped viruses such as HIV, hepatitis, influenza, encephalitis, coronavirus and herpes simplex virus.
Abstract: Lectins are unique proteins or glycoproteins of non-immune origin that bind specifically to carbohydrates. They recognise and interact reversibly to either free carbohydrates or glycoconjugates, without modifying their structure. Lectins are highly diverse and widely distributed in nature and have been extensively reported from various red algae species. Numerous red algae species have been reported to possess lectins having carbohydrate specificity towards complex glycoproteins or high-mannose N-glycans. These lectin-glycan interactions further trigger many biochemical responses which lead to their extensive use as valuable tools in biomedical research. Thus, owing to their exceptional glycan recognition property, red algae lectins are potential candidate for inhibition of various viral diseases. Hence, the present report integrates existing information on the red algae lectins, their carbohydrate specificity, and characteristics of purified lectins. Further, the review also reports the current state of research into their anti-viral activity against various enveloped viruses such as HIV, hepatitis, influenza, encephalitis, coronavirus and herpes simplex virus and other biomedical activities such as anti-cancer, anti-microbial, anti-inflammatory, anti-nociceptive and acaricidal activities.
64 citations
TL;DR: This study reported the highest protein and carbohydrate yields of the four technologies using high shear homogenization and an energy reduction up to 86% was achieved by applying a novel two-phase (macrostructure size reduction and cell disintegration) technique.
Abstract: The effect of osmotic shock, enzymatic incubation, pulsed electric field, and high shear homogenization on the release of water-soluble proteins and carbohydrates from the green alga Ulva lactuca was investigated in this screening study. For osmotic shock, both temperature and incubation time had a significant influence on the release with an optimum at 30 °C for 24 h of incubation. For enzymatic incubation, pectinase demonstrated being the most promising enzyme for both protein and carbohydrate release. Pulsed electric field treatment was most optimal at an electric field strength of 7.5 kV cm−1 with 0.05 ms pulses and a specific energy input relative to the released protein as low as 6.6 kWh kgprot
−1. Regarding literature, this study reported the highest protein (~ 39%) and carbohydrate (~ 51%) yields of the four technologies using high shear homogenization. Additionally, an energy reduction up to 86% was achieved by applying a novel two-phase (macrostructure size reduction and cell disintegration) technique.
TL;DR: It was concluded that Sph4 is a natural plant growth promoter that can be used as a raw material for biostimulants, and spermine could be an active compound and a metabolic indicator of Sph4 bioactivity.
Abstract: Developing new and natural sources of plant growth promotors is essential to ensure the safe and sustainable production of vegetables for human consumption. In recent years, the potential of microalgae as plant biostimulants has been investigated. Arthrospira platensis (Spirulina platensis) biomass is a recognized protein source and its enzymatic hydrolysis contains molecules such as polyamines with potential to promote plant growth. Therefore, the aim of the present study was to investigate the biostimulant properties of hydrolyzed biomass of A. platensis. Bioassays were performed to determine auxin-like and cytokinin-like bioactivity of the hydrolysates. In addition, its effect on lettuce seedling growth was investigated and an organic system field trail performed where yield and free polyamine levels in leaves quantified. The hydrolysates had a cytokinin-like effect in the bioassay. Foliar applications promoted the growth of lettuce seedlings with the 4-h reaction hydrolysate (Sph4) being the most effective at promoting growth and increasing the spermine content by 64% in the lettuce leaves. The polyamine concentration was also compared in non-hydrolyzed A. platensis and Sph4. Hydrolysis resulted in a 34% increase in spermine content. It was concluded that Sph4 is a natural plant growth promoter that can be used as a raw material for biostimulants, and spermine could be an active compound and a metabolic indicator of Sph4 bioactivity.
TL;DR: Using a half dose of chemical fertilizer with cyanobacteria is suggested to decrease rice production cost of farmers without any effects on rice quantity and quality.
Abstract: The effects of cyanobacteria and chemical fertilizer on growths and yields of rice (Oryza sativa L.) cv. Pathum Thani 1 were studied in pot trials. Nine treatments were set up without cyanobacteria and fertilizer (control), inoculated with cyanobacteria Nostoc carneum TUBT04 (T1), inoculated with Nostoc commune TUBT05 (T2), and inoculated with combination of N. carneum TUBT04 and N. commune TUBT05 (T3), full dose of recommended use of fertilizer (T4), half dose of recommended use of the fertilizer (T5), half dose of fertilizer combined with N. carneum TUBT04 (T6), half dose of fertilizer combined with N. commune TUBT05 (T7), and half dose of fertilizer combined with N. carneum TUBT04 plus N. commune TUBT05 (T8). Each treatment divides into five replications. Growth parameters including length and fresh and dry weights of shoot and root were measured in the seedlings. The number of spikes per plant and the amount and weight of rice grains per spike were measured after harvesting. The supplement with cyanobacteria promoted rice seedling growth and yield compared to the control treatment. Inoculation with cyanobacteria showed significant increase in root length (p = 0.41). In addition, the combined biofertilizer with a half of the recommended dose of chemical fertilizer significantly enhanced rice production including total number and weight of grain per spike and a total weight of 100 grains (p < 0.001). Therefore, using a half dose of chemical fertilizer with cyanobacteria is suggested to decrease rice production cost of farmers without any effects on rice quantity and quality.
TL;DR: Foliar application of 10% K or G sap along with 100% RDF is a recommendable option for improving yield and quality of rice and sustaining soil fertility in eastern Himalayas and similar agroecosystems elsewhere.
Abstract: Enhancing productivity through integrated nutrient management is pertinent to sustainable intensification of agricultural ecosystems. Field experiments were conducted during 2012 and 2013 in Eastern Himalayas with extracts from Kappaphycus alvarezii (K sap) and Gracilaria edulis (G sap) to assess growth, productivity and quality enhancement of rice (Oryza sativa). A Petri dish experiment was also conducted to assess the efficacy of saps in improving germination percentage and seedling vigour of rice seedlings. Field experiment included foliar spray of K and G saps (2.5, 5, 10 and 15% concentrations) with 100% recommended dose of fertilizers (RDF) along with water spray + 100% RDF (control). The rice seeds soaked with lower concentrations (2.5 and 5%) of K and G saps recorded higher germination percentage, root and shoot length and seedling vigour index as compared to water soaking. Whilst soaking in higher concentrations (7.5% and above) reduced the germination percentage and seedling vigour index. Foliar spray of K or G sap at 5% and above concentrations + 100% RDF significantly increased plant height, dry matter accumulation, chlorophyll index, crop growth rate, yield attributes and yield of rice (5.4 to 18.4% higher) as compared to control. Application of K or G sap at 10% concentrations + 100% RDF also increased micro-nutrient (Fe, Cu, Zn and Mn) and protein concentration in rice grains. Thus, foliar application of 10% K or G sap along with 100% RDF is a recommendable option for improving yield and quality of rice and sustaining soil fertility in eastern Himalayas and similar agroecosystems elsewhere.
TL;DR: Subcritical water extraction of fucoidan from Saccharina japonica was investigated in this paper, where a Box-Behnken design (BBD) was used to study the influences of temperature [100 − 180 −°C], pressure [20 − 80 −bar], solid to liquid (S/L) ratio [0.04 − 0.09 − g mL−1], agitation speed (AS) [100 -300 −rpm], and reaction time (RT) [5 − 15 −min].
Abstract: Subcritical water extraction (SWE) of fucoidan from Saccharina japonica was investigated. To optimize, a Box-Behnken design (BBD) was used to study the influences of temperature [100–180 °C], pressure [20–80 bar], solid to liquid (S/L) ratio [0.04–0.09 g mL−1], agitation speed (AS) [100–300 rpm], and reaction time (RT) [5–15 min]. By unraveling the regression equations, the optimal conditions were 127.01 °C, 80 bar, S/L ratio of 0.04 g mL−1, AS of 300 rpm, and RT of 11.98 min. Under these conditions, the crude fucoidan (CF) yield was 13.56%. FT-IR, monosaccharides, TGA and UV–Vis confirmed that the extracted polysaccharides had features of fucoidan. CF showed good antioxidant activities, while anti-proliferative activity showed a moderate cell proliferation for few cell lines. In conclusion, a high yield of CF with good functional activity obtained from SWE might be the favored method for industrial scale production of fucoidan.
TL;DR: In this article, the ability of the fast growing Chlorella vulgaris strain IPPAS C1 to accumulate phosphorus (P) was probed in V-shaped plastic foil photobioreactors.
Abstract: Algae are capable of accumulating nutrients from aqueous waste, which makes them a potential fertilizer. The ability of the fast growing Chlorella vulgaris strain IPPAS C1 to accumulate phosphorus (P) was probed in V-shaped plastic foil photobioreactors. The P uptake was 0.13–0.53 g(P)·m−2·day−1 when the algal culture densities were kept between 0.1 and 1.0 g(DW)·L−1 in a typical summer irradiance of Central Europe. The algal biomass can be effectively utilized for soil fertilization only if the algal cells release nutrients into the soil in a form that would be available to roots and at a rate sufficient to support plant growth. To examine this, we compared the growth of wheat, Triticum aestivum L., in two nutrient-deficient substrates: “Null Erde” and sand, with and without fertilization by wet and spray-dried algae. Plants grown in the two nutrient-deficient substrates supplemented by mineral fertilizer served as a control representing optimal nutrient supply. Plants grown in a high-nutrient substrate (SoMi 513) were used as an additional reference representing the maximum growth potential of wheat. Wheat growth was monitored for 8 weeks and measured, including the increase of the leaf area as well as shoot and root dry weight in 10 randomized replicates for each substrate and fertilization variant. After harvest, the biomass and N, P, and C contents of the plant shoots and roots were recorded. Algae fertilization of “Null Erde” led to wheat growth, including root hair production, which was similar to mineral-fertilized “Null Erde” and only slightly less vigorous than in the nutrient-rich SoMi 513 substrate. The plants grown in sand were smaller than the plants in “Null Erde” but fertilization by algae nevertheless led to growth that was comparable to mineral fertilizer. These results unambiguously demonstrate that algal biomass is a viable option for delivering nutrients to support agriculture on marginal soils.
TL;DR: Although all the strains demonstrated the ability to recover from different stress levels, the tropical strain was able to recover most rapidly while the Antarctic strain had the slowest recovery.
Abstract: The increased frequency of heat waves due to climate change poses a threat to all organisms. Microalgae are the basis of aquatic food webs, and high temperatures have significant impacts on their adaptation and survival rates. Algae respond to environmental changes by modulating their photosynthetic rates and biochemical composition. This study aims to examine the effect of elevated temperature on similar taxa of marine Chlorella originating from different latitudes. Strains from the Antarctic, temperate zone, and the tropics were grown at various temperatures, ranging from 4 to 38, 18 to 38, and 28 to 40 °C, respectively. A pulse-amplitude modulated (PAM) fluorometer was used to assess their photosynthetic responses. Parameters including maximum quantum efficiency (F
v/F
m), relative electron transport rate (rETR), and light harvesting efficiency (α) were determined from the rapid light curves (RLCs). In addition, the composition of fatty acids was compared to evaluate changes induced by the temperature treatments. Increasing the temperature from 35 to 38 °C for both Antarctic and temperate strains and from 38 to 40 °C for the tropical strain resulted in severe inhibition of photosynthesis and suppressed growth. Although all the strains demonstrated the ability to recover from different stress levels, the tropical strain was able to recover most rapidly while the Antarctic strain had the slowest recovery. The results underline that the thermal threshold for the analysed Chlorella strains temperature ranges between 38 and 40 °C. Furthermore, the analysed strains exhibited different trends in their response to elevated temperatures and recovery capabilities.
TL;DR: In this article, a cost-effective strategy was designed to purify fucoidans from the untapped brown algae Chnoospora minima (CMF) and Sargassum polycystum (SPF) harvested in Sri Lanka and to evaluate their cosmetizing properties.
Abstract: Over the years, bioactive and biocompatible natural products have received increased attention as ingredients of cosmeceutical formulations owing to their robust properties compared to many of the synthetic chemicals in use. Many natural products derived from algae have shown promising cosmetizing properties. Seaweed polysaccharides, in particular, have received increased attention for their biofunctional and physicochemical characteristics. This study aimed to design a cost-effective strategy to purify fucoidans from the untapped brown algae Chnoospora minima (CMF) and Sargassum polycystum (SPF) harvested in Sri Lanka and to evaluate their cosmetizing properties. Based on Fourier transform infrared (FTIR) spectroscopy and monosaccharide composition analysis, the purified polysaccharides were rich in fucoidan. Relatively high sulfate content was detected in both fucoidans. Experiments were carried out to evaluate antioxidant, UV-protective, anti-inflammatory, antiwrinkling, and skin-whitening effects. Both CMF and SPF showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) and alkyl radical-scavenging activities, anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, considerable collagenase and elastase inhibitory properties and skin-whitening effects via direct inhibition of tyrosinase, and intracellular melanin synthesis indicating promising cosmetizing effects.
TL;DR: In this paper, the effects of convective air-drying at 25, 40, and 70°C on the quality of the edible kelp Saccharina latissima to be used for food were investigated.
Abstract: The effects of convective air-drying at 25, 40, and 70 °C and freeze-drying on the quality of the edible kelp Saccharina latissima to be used for food were investigated. Based on the analysis of the carbohydrate and amino acid profiles, as well as polyphenol, fucoxanthin, and ash contents, no significant differences were detected among sample groups, and air-drying up to 70 °C results in equally nutritious products at shorter processing times. Only the iodine content was found lower in freeze-dried compared to air-dried samples. The swelling capacity of the air-dried samples was significantly lower than in freeze-dried samples, particularly at high temperatures (40 and 70 °C), reflecting alteration of the physico-chemical properties of the seaweed during air-drying (attributed to product shrinkage) and reduced capacity of the final product to rehydrate. Structural differences between air-dried products at 25 and 70 °C may explain the differences in mouthfeel perception (dissolving rate) among the two sample groups observed during a sensory evaluation. Overall, the drying temperature within this range did not alter neither the aroma (i.e. odor) nor the flavor intensity of the product. In food applications where the product’s mechanical properties (e.g. porosity) are essential, freeze-drying, and to a lesser extent, air-drying at low temperatures, will result in higher quality products than air-drying at higher temperatures.
TL;DR: It is exposed that LEGE CC strains have the potential or actual capacity to produce a variety of biotechnologically interesting compounds, including common cyanotoxins or unprecedented bioactive molecules.
Abstract: Cyanobacteria are a well-known source of bioproducts which renders culturable strains a valuable resource for biotechnology purposes. We describe here the establishment of a cyanobacterial culture collection (CC) and present the first version of the strain catalog and its online database (http://lege.ciimar.up.pt/). The LEGE CC holds 386 strains, mainly collected in coastal (48%), estuarine (11%), and fresh (34%) water bodies, for the most part from Portugal (84%). By following the most recent taxonomic classification, LEGE CC strains were classified into at least 46 genera from six orders (41% belong to the Synechococcales), several of them are unique among the phylogenetic diversity of the cyanobacteria. For all strains, primary data were obtained and secondary data were surveyed and reviewed, which can be reached through the strain sheets either in the catalog or in the online database. An overview on the notable biodiversity of LEGE CC strains is showcased, including a searchable phylogenetic tree and images for all strains. With this work, 80% of the LEGE CC strains have now their 16S rRNA gene sequences deposited in GenBank. Also, based in primary data, it is demonstrated that several LEGE CC strains are a promising source of extracellular polymeric substances (EPS). Through a review of previously published data, it is exposed that LEGE CC strains have the potential or actual capacity to produce a variety of biotechnologically interesting compounds, including common cyanotoxins or unprecedented bioactive molecules. Phylogenetic diversity of LEGE CC strains does not entirely reflect chemodiversity. Further bioprospecting should, therefore, account for strain specificity of the valuable cyanobacterial holdings of LEGE CC.
TL;DR: Results showed that Phormidium sp.
Abstract: Phycobiliproteins, light-harvesting pigments found in cyanobacteria and in some eukaryotic algae, have numerous commercial applications in food, cosmetic, and pharmaceutical industries. Colorant production from cyanobacteria offers advantages over their production from higher plants, as cyanobacteria have fast growth rate and high photosynthetic efficiency and require less space. In this study, three cyanobacteria strains were studied for phycobiliprotein production and the influence of sodium nitrate, potassium nitrate and ammonium chloride on the growth and phycobiliprotein composition of the strains were evaluated. In the batch culture period of 12 days, Phormidium sp. and Pseudoscillatoria sp. were able to utilize all tested nitrogen sources; however, ammonium chloride was the best nitrogen source for both strains to achieve maximum growth rate μ = 0.284 ± 0.03 and μ = 0.274 ± 0.13 day−1, chlorophyll a 16.2 ± 0.5 and 12.2 ± 0.2 mg L−1, and phycobiliprotein contents 19.38 ± 0.09 and 19.99 ± 0.14% of dry weight, whereas, for Arthrospira platensis, the highest growth rate of μ = 0.304 ± 0.0 day−1, chlorophyll a 19.1 ± 0.5 mg L−1, and phycobiliprotein content of 22.27 ± 0.21% of dry weight were achieved with sodium nitrate. The phycocyanin from the lyophilized cyanobacterial biomass was extracted using calcium chloride and food grade purity (A620/A280 ratio > 0.7) was achieved. Furthermore, phycocyanin was purified using two-step chromatographic method and the analytical grade purity (A620/A280 ratio > 4) was attained. SDS-PAGE demonstrated the purity and presence of two bands corresponding to α- and β-subunits of the C-phycocyanin. The results showed that Phormidium sp. and Pseudoscillatoria sp. could be good candidates for phycocyanin production.
TL;DR: 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.
Abstract: 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.
TL;DR: C-phycocyanin (C-PC) is a blue pigment often found in cyanobacteria that has commercial and biotechnological value as a nutraceutical for pharmaceutical and biomedical research, as well as a natural colorant for the cosmetic industry.
Abstract: C-phycocyanin (C-PC) is a blue pigment often found in cyanobacteria. It has commercial and biotechnological value as a nutraceutical for pharmaceutical and biomedical research, as well as a natural colorant for the cosmetic industry. Cyanobacteria from the Arthrospira (Spirulina) genus are one of the major sources of C-phycocyanin with up to 20% protein fraction. The biomass-solvent ratio, buffer concentration, temperature, and time regarding C-phycocyanin concentration, extract purity, and yield of C-phycocyanin were evaluated. The optimum extraction conditions for Arthrospira platensis were determined as a biomass-solvent ratio of 0.06 g mL−1 at 25 °C for 24 to 48 h. Temperature is an important factor in C-phycocyanin degradation. Citric acid was added as an edible preservative to increase the thermal stability of C-phycocyanin extracted from A. platensis, followed by incubation at 80 °C for 1 h. The initial concentration of C-phycocyanin with citric acid was reduced from 65 to 19% within 1 h; in contrast, the remaining C-phycocyanin concentration without citric acid reduced from 51 to 11%. The use of citric acid as an edible preservative increased the stability of C-phycocyanin in high thermal processing applications and extraction.
TL;DR: A new regular 1 → 3;1 → 4-α-L-fucan was obtained and showed anticancer activity in vitro towards human colon carcinoma cells comparable to the total fraction F1.
Abstract: The application of an ultrasound-assisted extraction method, combined with ion-exchange chromatography, has allowed separation of the total fucoidan fraction (F1) from the brown alga Fucus evanescens into two fractions, F2 and F3, in the ratio 1:0.2. The traditionally extracted F1 differs from F3 only by the acetate groups at C3 being somewhat predominant. F2 is described as having acetate groups located chaotically, and contains galactose and xylose residues, in addition to fucose. F3 consists of fucose residues acetylated almost exclusively at C3. Therefore, with ultrasound-assisted extraction from the brown alga Fucus evanescens, a new regular 1 → 3;1 → 4-α-L-fucan was obtained. It is sulphated at C2 and acetylated at C3 of the fucose residue and showed anticancer activity in vitro towards human colon carcinoma cells comparable to the total fraction F1.
TL;DR: In this article, the effects of eight plant growth regulators (PGRs), namely, salicylic acid (SA); 1-naphthaleneacetic acid (NAA); gibberellin (GA3); 6-benzylaminopurine (6-BA); 2,4-epibrassinolide (EBR); abscisic acid (ABA); ethephon (ETH); and spermidine (SPD) on the induction of lipids, proteins, carotenoids, and unsaturated fatty acids
Abstract: Microalgae are photosynthetic organisms with the ability to produce a variety of high-value compounds such as polyunsaturated fatty acids (PUFAs), proteins, pigments, and lipids. The high cost of microalgae production is one of the biggest obstacles for their commercialization. Plant growth regulators might be an ideal choice since they could potentially induce microalgae to produce lipids and other high-value secondary metabolites thereby reducing production cost. This study investigated the effects of eight plant growth regulators (PGRs), namely, salicylic acid (SA); 1-naphthaleneacetic acid (NAA); gibberellin (GA3); 6-benzylaminopurine (6-BA); 2,4-epibrassinolide (EBR); abscisic acid (ABA); ethephon (ETH); and spermidine (SPD) on the induction of lipids, proteins, carotenoids, and unsaturated fatty acids (UFAs) in Chlorella vulgaris. Moreover, the expression profiles of seven fatty acid biosynthethis genes were studied in the PGR-treated biomass. All PGRs used in the study caused significant increases in total lipid contents in non-dose-dependent manners when compared to control. However, lipid productivities were increased due to four of the eight PGRs (ABA, 6-BA, NAA, and ETH). Similar to lipids, total carotenoid contents were significantly higher in all of the PGR-treated microalgal biomass except ABA. However, soluble protein contents were not affected by the PGR treatments except SA at 10 mg L−1. Furthermore, 6-BA, NAA, ABA, and ETH treatments resulted in significant increases in UFAs especially DHA, linolenic acid, arachidonic acid, and EPA which were confirmed by the upregulation of fatty acid biosynthesis genes including stearoyl-ACP-desaturase, ω-3 fatty acid desaturase, biotin carboxylase, and acyl-acyl carrier protein. Our findings, therefore, indicate that the treatment with PGR used in this study could be a useful tool to produce biodiesel and other high-value metabolites from microalgal biomass.
TL;DR: Findings show that marine and freshwater macroalgae, as a raw material, have the optimal biologically active compounds composition for cosmetics.
Abstract: The biologically active compounds (fatty acids, pigments, phenolics, and flavonoid content) were studied in supercritical fluid extracts from the biomass of marine (Ulva clathrata, Cladophora glomerata, Polysiphonia fucoides, and their multi-species mixture) and freshwater (C. glomerata) macroalgae. Different extraction techniques were used in order to compare differences in the biologically active compound composition of the macroalgal extracts. The results indicated that the saturated and unsaturated fatty acids ranged from C9:0 to C22:0. The analysis of differences in the composition of unsaturated to saturated fatty acids in extracts showed that palmitic acid (C16:0) and oleic acid (C18:1, n-9) reached the highest value not only in marine monospecies and multi-species biomass but also in the freshwater macroalga C. glomerata. When comparing the similarity between the concentration of fatty acids and the ratio of the concentration of unsaturated fatty acids to saturated in macroalgal extracts, we found small but not statistically significant variations in values between years (up to 10%). This is acceptable for applications as a stable raw material for industrial purposes. Significantly higher values of fatty acids, carotenoids, and chlorophylls were obtained in the case of SC-CO2 extraction. The active ingredients of polyphenols, possessing antioxidant activity ranged from approximately 2-4%. Moreover, flavonoids represented less than 10% of the total content of polyphenolic compounds. The extraction efficiency of polyphenols was higher from a mixture of marine algae for the ultrasound-assisted extraction compared to freshwater. All these findings show that marine and freshwater macroalgae, as a raw material, have the optimal biologically active compounds composition for cosmetics.
TL;DR: For most of the targeted health outcomes in the selected clinical trials, daily consumption of Arthrospira biomass provided considerable benefits, however, more extensive studies that meet higher quality criteria are needed to confirm the reported results before any validated and absolute health claims can be made for this microorganism.
Abstract: Arthrospira (known commercially as Spirulina) is an edible cyanobacterium traditionally used for centuries as human food by various cultures. Its biochemical profile includes many bioactive molecules with enormous potential in human health. The aim of this paper is to systematically review the scientific evidence about the effects of dietary Arthrospira biomass consumption on a range of health outcomes. A search was made in PubMed and the Cochrane Library for randomised controlled clinical trials in which Arthrospira was used as a dietary supplement. An additional search was conducted for studies on rodents. Studies were organised by health outcomes. A total of 25 randomised clinical trials were included in the study. Four analysed the role of Arthrospira in dyslipidaemia, four in diabetes, one in hypertension, two in exercise, two in immune response, four in inflammation and precancerous lesions, and two in allergic rhinitis. Three studies analysed the antiviral effect of Arthrospira and a further three assessed its effect on nutritional status. For most of the targeted health outcomes in the selected clinical trials, daily consumption of Arthrospira biomass provided considerable benefits. However, more extensive studies that meet higher quality criteria are needed to confirm the reported results before any validated and absolute health claims can be made for this microorganism.
TL;DR: The contribution of A. esculenta to dietary cadmium intake does not appear to pose a threat to the consumer while the daily consumption of S. latissima leads to excessive iodine intakes, so the moderate consumption of these kelps will improve the iodine status in iodine-deficient populations.
Abstract: Samples of cultivated edible kelps Alaria esculenta and Saccharina latissima were analysed for their cadmium, iodine and inorganic arsenic contents. The inorganic arsenic levels were low in both species but samples of A. esculenta had relatively high cadmium contents (up to 2.01 mg kg−1 dry weight (DW)), and iodine levels were high in S. latissima samples (up to 6568 mg kg−1 DW), exceeding the limits established by the French food safety authority for both elements. Simple soaking treatments in warm fresh water (32 °C) reduced the iodine in S. latissima and treatment of A. esculenta in hypersaline solution (2.0 M NaCl) reduced the relative cadmium content. However, both treatments affected the nutrient content of the biomass, illustrated by considerable variations in DW and the content of bioactive compounds (e.g. minerals, polyphenols, fucoxanthin). Health risks associated with the consumption of these seaweed species were estimated using risk factors based on established tolerable intake levels. The contribution of A. esculenta to dietary cadmium intake does not appear to pose a threat to the consumer while the daily consumption of S. latissima leads to excessive iodine intakes. The moderate consumption of these kelps will, on the other hand, improve the iodine status in iodine-deficient populations.
TL;DR: Hydlysis with xylanase is a feasible choice to extract proteins of good quality from P. palmata with the method described within this study but might be an optimal method to examine the bioactivity by extracting the protein hydrolysates.
Abstract: The red seaweed Palmaria palmata has previously been reported to have high protein content high in essential amino acids. To extract the proteins a rigid cell wall consisting mainly of β-(1→4)/β-(1→3)-D-xylans must be disrupted. Different methods have been used to overcome this problem along with various methods used for protein evaluation. In this study, the effect of enzymatic pre-treatment on protein extraction was examined. Both enzymatic hydrolysis with xylanase and protease were tested. The amino acid content of the fractions was examined after extraction. The amino acid composition was similar to what has previously been reported; P. palmata was high in essential amino acids. Accordingly, a nitrogen-to-protein conversion factor was calculated for each fraction individually and protein results were compared with calculation using the proximate 6.25 conversion factor. The nitrogen-to-protein conversion factor varied between fractions but all factors were significantly lower than the popularly used 6.25 indicating that this conversion factor for processed P. palmata is effectively and considerably overestimating the protein content. Enzymatic pre-treatment with xylanase resulted in enhanced amino acid content and successful protein extraction. Enzymatic hydrolysis using protease resulted in higher protein content in the liquid extract compared to hydrolysis with xylanase, due to the release of proteins, peptides, and amino acids. Therefore, hydrolysis with protease is not suitable to extract proteins from P. palmata with the method described within this study but might be an optimal method to examine the bioactivity by extracting the protein hydrolysates. However, the result from this study confirm that hydrolysis with xylanase is a feasible choice to extract proteins of good quality from P. palmata.
TL;DR: The results suggest that the use of water-soluble polysaccharides from U. rigida at 10 mg kg−1 dose improve growth, immune responses, and antioxidant activity in M. cephalus in a dose-dependent manner after challenge with P. damselae.
Abstract: This study was carried out to investigate and compare the effect of water-soluble polysaccharides extract of the green alga, Ulva rigida (WPU), as a dietary supplement on growth performance, antioxidant enzyme activity, non-specific immune responses, and disease resistance of juvenile grey mullet, Mugil cephalus, subjected to bacterial infection with Photobacterium damselae. Three replicate groups of fish (initial mean weight, 15 ± 0.1 g) were fed with four isonitrogenous and isolipidic diets containing four levels, 0 or control, 5, 10, and 15 mg kg−1 of WPU (WPU0 or control, WPU5, WPU10, and WPU15) for 8 weeks over the growth trial. Thereafter, ten fish from each dietary treatment were infected with bacteria P. damselae to evaluate disease resistance of infected fish. Feeding grey mullet at 10 mg kg−1 WPU level (WPU10 diets) produced higher weight gain (211.36 ± 6%), specific growth rate (1.88 ± 0.03%) and protein efficiency ratio (4.26 ± 0.1%) compare to the control group. The diets supplemented with three levels of WPU-stimulated lysozyme, phagocytic, and respiratory burst activity of fish, but, the stimulatory capacities of the extracts varied greatly, depending on the concentrations used and diet; WPU10 was higher than WPU 5 and WPU15 diets. The best responses in antioxidant enzyme activities of superoxide dismutase (4.8 U mL−1), glutathione (3.6 U mL−1), and malondialdehyde (25.0 U mL−1) were induced by the extracts obtained from WPU10 diet. In addition, using WPU extract in all diets decreased mortality in M. cephalus in a dose-dependent manner after challenge with P. damselae. These results suggest that the use of water-soluble polysaccharides from U. rigida at 10 mg kg−1 dose improve growth, immune responses, and antioxidant activity in M. cephalus.