Macroalgal blooms are ecological responses to nutrient enrichment in shallow seagrass-dominated estuaries. For decades the Indian River Lagoon (IRL) a biodiverse estuary in east-central Florida, has experienced persistent blooms of red drift macroalgae, including Gracilaria and Hypnea spp. Since 2013, extensive blooms of green macroalgae, such as Chaetomorpha and Ulva spp., have developed. To better understand IRL nutrient effects on bloom-forming macroalgae, field and laboratory studies (2012) assessed nitrogen (N) versus phosphorus (P) limitation and morphological/physiological characteristics in relatively urbanized (Titusville, FL) versus rural (Fort Pierce, FL) IRL segments. Field studies indicated Ulva lactuca, Hypnea musciformis, and Gracilaria tikvahiae all grew fastest in Titusville (average ± SD; 0.49 ± 0.07, 0.35 ± 0.03, and 0.14 ± 0.05 doublings d−1, respectively). However, U. lactuca had the most rapid biomass doubling time (2 days). Laboratory nutrient en- richment assays revealed 3-fold increases in rapid light curve (RLC) maximum values and 2-fold faster growth at high concentrations of N and P for U. lactuca. This superior growth and photosynthesis was attributed to higher surface area:volume ratios averaging (± coefficients of variation, %) 565.2 ± 2.15 cm2 g dry wt.− 1 compared to lower ratios for H. musciformis (110.7 ± 3.97 cm2 g dry wt.−1) and G. tikvahiae (91.1 ± 1.81 cm2 g dry wt.−1). Finely- and coarsely-branched H. musciformis and G. tikvahiae were similar photosynthetically but not morpho- logically based on a functional/form model. These data provide a physiological basis explaining bloom distribu- tions and the recent success of green macroalgae in the increasingly eutrophic IRL.
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Laminaran, porphyran, and ulvan are major seaweed polysaccharides in brown, red, and green algae, respec- tively. We compared their prebiotic effects using individual microbial fermentability test and in vitro fecal fer- mentation. The fermentability test showed that these polysaccharides were selectively utilized by Bifidobacteria, Lactobacilli, and Bacteroides (ΔOD580 nm, 0.2–1.0), while no growth of harmful bacteria was observed. In vitro fecal fermentation for 24h showed growth stimulation effect of laminaran on Bifidobacteria (Δ8.3%/total bacteria) and Bacteroides (Δ13.8%/total bacteria) promoting the production of acetate and propionate. Ulvan exhibited same result on Bifidobacteria (Δ8.5%/total bacteria) and Lactobacillus (Δ6.8%/total bacteria) pro- moting the production of lactate and acetate; however, porphyran showed little prebiotic effect. Laminaran was fermented slowly compared to fructooligosaccharides and this may permit production of short-chain fatty acids in distal colon. This in vitro study demonstrates that the seaweed polysaccharides tested, particularly laminaran and ulvan, have prebiotic effects on microbiota in human colon.
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Agar is produced on commercial scale from August, 1999 onwards in the Agar Plant at Re,gional Centre of Central Marine Fisheries Research Institute, Mandapam C;unp using the red seaweed Graci/aria edulis (Kanji Pasi) as raw material. Agar is manufactured in sheet fonn by washing the dried seaweed in the ~gitator tank, treating with Hc1, cooking in the digester by passing steam, collecting the agar gel in aluminium trays, freezing the gel in freezing unit, thawing, bleaching and sun-drying of agar sheets. The yield of agar is found to be 6 to 8%. The gel strength, gelling and melting temperature of 1.5% agar ranged from 74 to 122 gicm', 44 to 46"C and 95 to 97"C respectively. The bleacbed agar sheets are marketed by packing them in polythene bags. The methods for improving the yield and quality of agar are suggested.
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The development of an integrated biorefinery process capable of producing multiple products is crucial for commercialization of microalgal biofuel production. Dilute acid pretreatment has been demonstrated as an effi- cient approach to utilize algal biomass more fully, by hydrolyzing microalgal carbohydrates into fermentable sugars, while making the lipids more extractable, and a protein fraction available for other products. Previously, we have shown that sugar-rich liquor could be separated from solid residue by solid–liquid separation (SLS) to produce ethanol via fermentation. However, process modeling has revealed that approximately 37% of the solu- ble sugars were lost in the solid cake after the SLS. Herein, a Combined Algal Processing (CAP) approach with a simplified configuration has been developed to improve the total energy yield. In CAP, whole algal slurry after acid pretreatment is directly used for ethanol fermentation. The ethanol and microalgal lipids can be sequentially recovered from the fermentation broth by thermal treatment and solvent extraction. Almost all the monomeric fermentable sugars can be utilized for ethanol production without compromising the lipid recovery. The techno- economic analysis (TEA) indicates that the CAP can reduce microalgal biofuel cost by $0.95 per gallon gasoline equivalent (GGE), which is a 9% reduction compared to the previous biorefinery scenario.
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Biochar properties are significantly influenced and controlled by biomass feedstock type and pyrolysis operating conditions, and the development of multiple biochar properties for various applications has necessitated the need for blending different feedstocks together. Co-pyrolysis as a potential technology has been proposed to improve the overall performance of biomass pyrolysis and has proved effective in improving biochar properties. Consequently, the combination of lignocellulosic and macroalgae biomasses has been targeted for biochar production and improvement of biochar properties through co-pyrolysis. This paper therefore presents a critical review of biochar production from co-pyrolysis of lignocellulosic and macroalgae biomass (CLMB). It discusses the biomass feedstock selection, characterization, pre-processing and suitability for thermal processing; and analyzes biochar production, characterization and reactor technologies for CLMB. Furthermore, the potential and economic viability of biochar production system from CLMB are highlighted; and finally, the current state and future directions of biochar production from CLMB are extensively discussed.
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PDF on final report of 'Preliminary Study - Chinese Market for Seaweed and Carrageenan Industry'.
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e investigated the effects of halogenated furanones from the red alga Delisea pulchra on colonisation of surfaces by marine bacteria. Bacterial abundance on the surface of D. pulchra, assessed using scanning electron microscopy (SEM),was significantly lower than on the surfaces of 3 co-occur- ring algal species, all of which lack furanones.There was also a strong inverse correlation between bac- terial abundance and furanone content (previously determined) for different sections of the thallus of D. pulchra, consistent with inhibition of bacteria by furanones. Based on these observations we experi- mentally investigated inhibition of marine bacteria by furanones, initially testing the effects of crude extract of D. pulchra (about 5 0 % of which is furanones) on the growth of 144 strains of bacteria isolated from the surfaces of D.pulchra, nearby rocks, or a CO-occurringalga (Sargassum vestjtum) This crude extract did not strongly inhibit growth of these bacteria; 79% of the strains grew at 50 pg ml-' of crude extract, and 63% grew at 500 pg ml-'. Inhibition of growth that did occur was strongly source depen- dent, with bacteria isolated from rocks the least affected, and strains from D. pulchra the most. As inhi- bition of growth did not provide an adequate explanation for the inverse relationship between levels of furanones and bacteria abundance on D.pulchra, we proceeded to investigate the effects of these metabolites on other bacterial characteristics relevant to colonisation-attachment, swarming, and swimming. lndividual furanones or crude extract at natural concentrations strongly inhibited bacterial attachment in the laboratory and in the field. In laboratory assays, attachment of 3 strains isolated from rocks was much more strongly affected than that of 3 isolates from D. pulchra, in contrast to the pattern for growth inhibition. We also tested individual furanones against swimming and swarming of the same 6 bacterial isolates (3 from rocks, 3 from D. pulchra) used in the attachment assays. At least some fura- nones inhibited swarming or sulmming at non-growth-inhibitory concentrations for all isolates, again indicating specific effects against bacterial characteristics. As for attachment, there were significant dif- ferences in the responses of different isolates to furanones. We also found that the ability to swarm was widespread among these surface associated marine bacteria, suggesting that swarming may be ecolog- ically important in these systems. Overall, we found that the effects of furanones on bacteria varied a m o n g ( 1 ) f u r a n o n e s , ( 2 ) b a c t e r i a l p h e n o t y p e s , ( 3 ) d i f f e r e n t i s o l a t e s a n d ( 4 ) d i f f e r e n t s o u r c e s of i s o l a t i o n (e.g. rocks or algae). This differential inhibition of different bacterial isolates or phenotypes by fura- nones, as well as affecting overall bacterial abundance on the alga, should have strong effects on the species composition of the bacterial community on the alga's surface. The effects of furanones on spe- cific bacterial colonisation traits are discussed in the light of recent evidence demonstrating that fura- nones interfere with bacterial acylated homoserine lactone regulatory systems.
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Although numerous algal products have antimicrobial activity, limited knowledge of metabolite localisation and presentation in algae has meant that ecological roles of algal natural products are not well understood. In this study, extracts of Asparagopsis armata had antibacterial activity against marine (Vibrio spp.) and biomedical (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus spp.) strains. The major natural products in both life-history stages of A. armata (as determined by gas chromatography-mass spectrometry analysis [GC-MS]) were bromoform (0.58 to 4.3% of dry weight [DW]) and dibromoacetic acid [DBA] (0.02 to 2.6% DW), and each compound was active against these same bacteria. To resolve whether this antibiotic activity was ecologically rele- vant, we examined the localisation of metabolites in the specialised cells of A. armata and observed a delivery mechanism for the release of metabolites to the surface. Bromoform and DBA were sub- sequently quantified in the surrounding medium of laboratory cultures, establishing their release from the alga. In a novel ecological test of algal natural products, halogenated metabolites in A. armata were manipulated by omitting bromine from an artificial seawater medium. Significantly higher densities of epiphytic bacteria occurred on algae that no longer produced halogenated metabolites. Both bromoform and DBA were more active against bacteria isolated from algae lacking brominated metabolites than algae producing normal amounts of these compounds. Taken together, these results indicate that halogenated metabolites of A. armata may be important in reducing epiphytic bacterial densities.
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Results obtained on seasonal growth, yield and physical properties of agar in Gelidiella acerosa and Gracilaria edulis for a period of one year are presented. Vegetation of these two species occurred throughout the year with two peak growth periods.
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2What is HTL and why do we care?Hydrothermal liquefaction (HTL) is...the thermochemical conversion of biomass in a hot, pressurized water environment to break downsolid biopolymer structures to predominantly liquid componentsIt stands out among thermal conversion processes because...•HTL is a conceptually simple (i.e., heated pipe), scalable, and robust continuous process that canaccept a diverse range ofwet feedstocks(no drying!)•HTL results inhigh carbon yieldsto liquid hydrocarbons (up to 60%)•HTL produces a gravity-separable biocrude with low oxygen content (5–15 %) that can beupgraded in a single stage hydrotreater
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
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