Growth of microalgae on undiluted anaerobic digestate of piggery effluent with high ammonium concentrations

Anaerobic digestate of piggery effluent (ADPE) is extremely high in ammonia toxic to many microorganisms. Bioprospecting and nutrient enrichment of several freshwater and wastewater samples combined and further acclimation resulted in a mixed culture containing at least three microalgae species capable of growing on undiluted ADPE. Outdoor growth of the mixed culture using raceway ponds showed potential for up to 63.7 ± 12.1 mg N-NH4 + L −1 d −1 ammonium removal from the ADPE. The microalgal consortium was dominated by Chlorella sp. and was stable at between 800 and 1600 mg N-NH4 + L −1. Regulation of CO2 addition to the ponds to maintain a pH of 8 increased chlorophyll content of the microalgal consortium. Average microalgal biomass productivity of 800 mg N-NH4 + L −1 culture conditions during five weeks semicontinuous growth was 18.5 mg ash-free dry weight L −1 d −1. Doubling the ammonium concentration from 800 to 1600 mg N-NH4 + L −1 resulted in a 21% reduction of productivity, however the culture grown at 1600 mg N-NH4 + L −1 with the addition of CO2 by keeping pH at pH = 8 led to a 17% increase in biomass productivity

Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degree. Due to the large exposure of about 150 m2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 GeV and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003 (stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure

Calculation of the Flux of Atmospheric Neutrinos

Atmospheric neutrino-fluxes are calculated over the wide energy range from 30 MeV to 3,000 GeV for the study of neutrino-physics using the data from underground neutrino-detectors. The atmospheric muon-flux at high altitude and at sea level is studied to calibrate the neutrino-fluxes at low energies and high energies respectively. The agreement of our calculation with observations is satisfactory. The uncertainty of atmospheric neutrino-fluxes is also studied.Comment: 51 page

Growth comparison of microalgae in tubular photobioreactor and open pond for treating anaerobic digestion piggery effluent

The overwhelming interest in the use of microalgae to handle associated nutrient surge from anaerobic digestion technologies for the treatment of wastewater, is driven by the need for efficient nutrient recovery, greenhouse gas mitigation, wastewater treatment and biomass reuse. Here, the feasibility of growth and ammonium nitrogen removal rate of semi-continuous mixed microalgae culture in paddle wheel-driven raceway pond and helical tubular closed photobioreactor (Biocoil) for treating sand-filtered, undiluted anaerobic digestion piggery effluent (ADPE) was compared under outdoor climatic conditions between June and September 2015 austral winter season. Two Biocoils, (airlift and submersible centrifugal pump driven) were tested. Despite several attempts in using airlift-driven Biocoil (e.g. modification of the sparger design), no net microalgae growth was observed due to intense foaming and loss of culture. Initial ammonium nitrogen concentration in the Biocoil and pond was 893.03 ± 17.0 mg NH4 +-N L-1. Overall, similar average ammonium nitrogen removal rate in Biocoil (24.6 ± 7.18 mg NH4 +-N L-1 day-1) and raceway pond (25.9 ± 8.6 mg NH4 +-N L-1 day-1) was achieved. The average volumetric biomass productivity of microalgae grown in the Biocoil (25.03 ± 0.24 mg AFDW L-1 day-1) was 2.1 times higher than in raceway pond. While no significant differences were detected between the cultivation systems, the overall carbohydrate, lipid and protein contents of the consortium averaged 29.17 ± 3.22, 32.79 ± 3.26 and 23.29 ± 2.15% AFDW respectively, revealing its suitability as animal feed or potential biofuel feedstock. The consortium could be maintained in semi-continuous culture for more than three months without changes in the algal composition. Results indicated that microalgae consortium is suitable for simultaneous nutrient removal and biomass production from piggery effluent

Batch cultivation of microalgae in anaerobic digestate exhibits functional changes in bacterial communities impacting nitrogen removal and wastewater treatment

Within the biorefinery concept, microalgal cultivation has potential as one component of the wastewater treatment toolkit for anaerobic digestates. Recovering nutrients from digestate such as anaerobic digestate of piggery effluent, has been well demonstrated with Scenedesmus sp. and Chlorella sp. in mixed cultures. Less understood during microalgae cultivation, is the participation of bacterial communities as they play a fundamental role in biological nutrient cycling processes with potential to optimise algal productivity and nutrient recovery. To this end, we batch cultivated microalgae on increasing concentrations of digestate (250, 500 and 890 mg N NH4+ L−1), took samples under time series and quantified culture conditions including water chemistry properties with a focus on nitrogen values during treatment. Chlorophyll and dry weight were measured to provide reasonable estimates of the health of the microalgal culture. We additionally characterised the bacterial community using next generation 16S rRNA sequencing on the ION torrent, followed by an in-silico analysis of functional nitrogen and carbon cycling genes using PICRUSt. Our data suggest the microalgae form symbiotic relationships with a number of bacterial groups including Bacteriodetes, Cyanobacteria, nitrifying and N-fixing bacteria. These microalgae-microbial consortia favour NH4+ and NO2− removal possibly via nitrification and nitrifier denitrification pathways while accumulating NO3− in the inoculated diluted digestate treatment systems. In the absence of inoculation and at high ammonium concentrations in the digestate, almost all NH4+, NO2− and NO3− are driven from the system, largely due to stripping and are unable to be captured for any further use. Thus, a microalgae-microbial consortia-driven digestate treatment system offers the potential to recapture and recover N, enabling production of N fertiliser. These data demonstrate the integral role of syntrophic relationships for microalgae and bacteria in third generation biorefinery concepts

Nutritional profile and in vitro digestibility of microalgae grown in anaerobically digested piggery effluent

Microalgal biomass grown in wastewater can be a sustainable source of animal feedstock. We have previously shown the feasibility of mass algal cultivation on undiluted anaerobic digested piggery effluent (ADPE). In this study, we evaluated the nutritional value, pathogen load, in vitro digestibility and potential physiological energy (PPE) of ADPE-grown microalgae as a potential feedstock for pigs. Pathogen load of ADPE-grown microalgae was within regulatory limits. Crude protein of ADPE-grown microalgae was higher than full fat soybeans but was much lower than conventional soybean meals (SBM) currently employed as a source of protein in pig feeds. The essential amino acid content of the microalgae was also lower than SBM. Fatty acid composition of the microalgae was favourable with an omega-3:omega 6 ratio of ~1.9, which may offer potential for value-adding use in some diets. In vitro digestibilities were higher in faeces than at the ileum and were lower for the defatted microalgal biomass. The (theoretical) net energy values of ground and bead-milled algae samples were found to be comparable to that of deshelled sunflower meal used as a feeding ingredient for pigs, but were lower than SBM

Dose-dependent effects of flumazenil on cognition, mood, and cardio-respiratory physiology in healthy volunteers

Objectives: To assess the possible effects of flumazenil on cognitive processing, physiology, and mood. Design: A double-blind, placebo controlled, four-way cross-over study, using healthy volunteers. Methods: On each of 4 separate visits, 16 participants received 0.5mg, 2.5mg, 5.0mg of flumazenil, or normal saline. They then performed a computerised test battery assessing cognitive function. Measures of pulse rate, arterial oxygen saturation and mean arterial pressure were also taken. Finally, participants completed visual analogue scales assessing their subjective mood state. Results: The majority of cognitive tasks showed dose-dependent declines in performance. Mean arterial pressure was significantly reduced, as was pulse rate. Subjective alertness showed a similar decline. Conclusions: Flumazenil has been clinically described as an agent with few intrinsic properties, whose primary effect lies in its ability to reverse benzodiazepine-induced states. This study has shown that flumazenil does possess intrinsic activity which have a significant effect on cognition, cardiovascular physiology and mood. Clinicians need to be aware of these effects

A molecular perspective of the genetic relationships of G-protein coupled melatonin receptor subtypes

Successful cloning of melatonin receptors from various target tissues in the past few years has increased our understanding of the molecular signal transduction mechanisms of G-protein coupled melatonin receptors, of which three subtypes (MEL-1A, MEL-1B, and MEL-1C) have been reported in different vertebrates. Based upon melatonin receptor sequences available in the Genbank database, we have performed phylogenetic analyses of the nucleotide and encoded amino acid sequences of G-protein-coupled melatonin receptors, and determined the range of amino acid identities between melatonin receptors of the same and different subtypes. Besides the three well-known subtypes, a potential novel subtype of MEL-1D, as exemplified by unique separation of Xenopus X2.0 sequence (Genbank accession No. U31826) from the others in the protein phylogenetic tree, possibly exists. In addition, one of the chicken brain melatonin receptor sequences has been identified as belonging to the MEL-1B subtype. Our analyses showed that melatonin receptors of the same subtype and different subtypes are likely to share ≥75% and <65% amino acid identities, respectively. Phylogenetic analysis based on amino acid comparisons will be needed to determine the subtype status of any pair of melatonin receptor sequences that exhibit ≥65% to <75% amino acid identity. Despite the usefulness of genetic relatedness in the subtype classification of G-protein-coupled melatonin receptors, functional correlation of molecular structure may ultimately prove the most comprehensive approach in melatonin receptor classification. © Munksgaard.link_to_subscribed_fulltex