Comparison of various microbial inocula for the efficient anaerobic digestion of Laminaria hyperborea

Background: The hydrolysis of seaweed polysaccharides is the rate limiting step in anaerobic digestion (AD) of seaweeds. Seven different microbial inocula and a mixture of these (inoculum 8) were therefore compared in triplicate, each grown over four weeks in static culture for the ability to degrade Laminaria hyperborea seaweed and produce methane through AD. Results: All the inocula could degrade L. hyperborea and produce methane to some extent. However, an inoculum of slurry from a human sewage anaerobic digester, one of rumen contents from seaweed-eating North Ronaldsay sheep and inoculum 8 used most seaweed volatile solids (VS) (means ranged between 59 and 68% used), suggesting that these each had efficient seaweed polysaccharide digesting bacteria. The human sewage inoculum, an inoculum of anaerobic marine mud mixed with rotting seaweed and inoculum 8 all developed to give higher volumes of methane (means between 41 and 62.5 ml g-1 of seaweed VS by week four) ,compared to other inocula (means between 3.5 and 27.5 ml g-1 VS). Inoculum 8 also gave the highest acetate production (6.5 mmol g-1 VS) in a single-stage fermenter AD system and produced most methane (8.4 mL mmol acetate-1) in phase II of a two-stage AD system. Conclusions: Overall inoculum 8 was found to be the most efficient inoculum for AD of seaweed. The study therefore showed that selection and inclusion of efficient polysaccharide hydrolysing bacteria and methanogenic archaea in an inoculum offer increased methane productivity in AD of L. hyperborea. This inoculum will now being tested in larger scale (10L) continuously stirred reactors optimised for feed rate and retention time to determine maximum methane production under single-stage and two-stage AD systems.Marie Curie Senior Researcher Fellowship (SEAWEED AD

Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships

Due to the geographical location and paleobiogeography of the Canary Islands, the seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These are Bryopsidella neglecta (Berthotd) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck, Hincksia onslowensis (Amsler et Kapraun)P.C. Silva, Syringoderma floridana Henry, Peyssonnelia harveyana J. Agardh, Cryptonemia seminervis(C. Agardh) J. Agardh, Botryodadia wynnei Ballantine, Gloiocladia blomquistii (Searles) R. E.Norris, PIahchrysis peltata (W. R. Taylor) P. Huv4 et H. Huv4, Leptofauchea brasiliensis Joly, and Sarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae,support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions

Uptake of inorganic nitrogen and seaweed surface area: Volume ratios

Surge uptake of ammonium and nitrate by four intertidal seaweed species was examined under standard conditions (16.5 or 20[deg]C, 72 [mu]E m-2 s-1), at both subsaturating and saturating initial nutrient concentrations. Uptake rates were positively correlated with the surface area: volume (SA:V) ratio of the thallus: Ulva curvata (Kutzing) DeToni > Fucus evanescens C. Agardh [approximate] Gracilaria tikvahiae McLachlan > Codium decorticatum (Woodward) Howe. A positive correlation was also found for the relationship between SA:V and the initial slope of the curves of uptake rate vs. external concentration. These results support the predictions of an earlier funtional-form model, and suggest the usefulness of the SA:V ratio as a comparative index of nutrient uptake capability in co-occurring seaweeds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24729/1/0000151.pd

Experimental evidences for the use of two macroalgal species, Ascophyllum nodosum and Fucus vesiculosus as biomonitors of N sources

Proyecto ANILE (CTM2009-08396, CTM2010-08804-E) Plan Nacional de I+D+i y Proyecto RADIALES (IEO)Postprint2,263

Physiological responses and productivity of the seaweed Ulva ohnoi (Chlorophyta) under changing cultivation conditions in pilot large land-based ponds

Land based intensive cultivation systems have been proposed as an ideal option for the commercial production of high value products from seaweeds. However, many cultures on Ulva and other seaweeds are based on relatively small-scale facilities. The high variability of culture conditions can strongly affect the physiological performance of seaweeds, but few studies examine their phenotypic plasticity by integrating critical biological descriptors, e.g. photobiology, oxidative stress, nutrient acquisition. The purpose of this study was to determine the physiological plasticity and growth of Ulva ohnoi during its cultivation in land-based 40 m3 ponds. Through an entire culti-vation cycle (four-weeks), photosynthesis, respiration, pigments, antioxidant capacity and nutrient content were measured. Light, temperature, pH, and dissolved inorganic nitrogen (DIN) were simultaneously monitored in seawater. Additionally, the N-uptake kinetics of U. ohnoi were examined in the laboratory in order to explain the efficiency of the seaweed biomass for DIN-incorporation in the ponds after fertilization. Generally, the gradual increase in seaweed density throughout the cultivation period was directly associated to a drop in light avail-ability and dissolved inorganic carbon (i.e. higher pH) within the ponds. These changes in cultivation conditions were related to a reduction of photosynthetic capacities, nutrient content and growth of U. ohnoi. N-uptake kinetics of U. ohnoi and the behavior of DIN within the ponds after fertilization, indicated that U. ohnoi was able to incorporate ammonium more efficiently than nitrate, and the presence of the former likely inhibits nitrate acquisition. The understanding of the capacity of U. ohnoi to acclimate to the extreme changing culture condi-tions, could be applied to improve its productivity and chemical composition.En prens