Enhancing performance in anaerobic high-solids stratified bed digesters by straw bed implementation

Anaerobic high-solids single-stage stratified bed digesters have been found to be simple and flexible design candidates for small-scale reactors located in medium- to low-technology environments. In the present study, wheat straw was used as the starter material for the stratified bed. Upon green mass feeding, the anaerobically stabilised straw bed functioned both as a biofilm support and as a particulate filter. It enabled a direct onset of 7 kg VSm(-3) batch loads, added twice a week, and permitted a low but consistent bed permeability during feeding at an average superficial flow velocity of 1 m d(-1) to be achieved. Fed-batch tests with sugar beet tops in pilot- and laboratory-scale setups at an average loading rate of 2 kg VSm(-3) d(-1) resulted in average biogas production rates of 1.2-1.4 m3 m(-3) d(-1) and methane yields of 0.31-0.36 m3 kg(-1) VS(added). At the end of the laboratory-scale feeding trial, the 200 day old straw bed had compacted to 50% of its initial volume, without any negative effects on performance being detectable

Use of a capacitive affinity biosensor for sensitive and selective detection and quantification of DNA—A model study

AbstractA capacitive DNA-sensor model system was used to monitor the capture of complementary single-stranded DNAs. The sensor chip consisted of a gold electrode, which was carefully insulated with a polytyramine layer and covalently tagged with 25-mer oligo-C. As low as 10−11 moles per liter of target oligo-G could be detected by injecting 250μL of sample. Elevated temperature was used to reduce non-specific hybridization. Less than 10% of non-target 25-mer oligo-T interacted nonspecifically with the oligo-C probes when hybridization process was performed at 50°C. Studying the relationship of length of the analyte to the signal strength, the output from the capacitive DNA-sensor increased to almost the double; from 50 to 88-nFcm−2, when a 25-mer oligo-G was used instead of a 15-mer. By sandwich hybridization at room temperature, it was possible to further increase the signal, from 78-nFcm−2 for the target 50-mer oligo-G alone, to 114-nFcm−2

Chromato-panning: an efficient new mode of identifying suitable ligands from phage display libraries

<p>Abstract</p> <p>Background</p> <p>Phage Display technology is a well established technique for high throughput screening of affinity ligands. Here we describe a new compact chromato-panning procedure for selection of suitable binders from a phage peptide display library.</p> <p>Results</p> <p>Both phages and <it>E. coli </it>cells pass non-hindered through the interconnected pores of macroporous gel, so called <it>cryogel</it>. After coupling a ligand to a monolithic cryogel column, the phage library was applied on the column and non-bound phages were washed out. The selection of strong phage-binders was achieved already after the first panning cycle due to the efficient separation of phage-binders from phage-non-binders in chromatographic mode rather than in batch mode as in traditional biopanning procedures. <it>E. coli </it>cells were applied on the column for infection with the specifically bound phages.</p> <p>Conclusion</p> <p>Chromato-panning allows combining several steps of the panning procedure resulting in 4–8 fold decrease of total time needed for phage selection.</p

Park- och trädgårdsavfall

Park- och trädgårdsavfall hanteras i ansenliga mängder i Sverige, ca 450 000 ton per år. Normalt används den mer vedartade delen i (kraft)värmeverk och den resterande mängden komposteras. Den del som går till förbränning ger i dagsläget relativt god ekonomisk utdelning, om den är fri från föroreningar och har hög torrsubstanshalt. Den resterande mer lättnedbrytbara delen av avfallet borde dock kunna utnyttjas bättre, då kompostering leder till höga behandlingskostnader utan att någon energi kan tas tillvara. Här kan biogasproduktion vara en möjlighet. Detta projekt har bestått av tre delar där en framsiktad kompostråvara ur krossat park- och trädgårdsavfall har utvärderats utifrån möjligheten att använda en större andel av materialet som fastbränsle, dess biogaspotential och möjligheten att använda rötresten från denna biogasproduktion som biogödsel i jordbruket

Performance of biofilm carriers in anaerobic digestion of sisal leaf waste leachate

Three methanogenic biofilm bioreactors were studied to evaluate the performance of three types of carriers. The carrier material were consisted of sisal fibre waste, pumice stone and porous glass beads, and the bioprocess evaluated was the methanogenesis anaerobic digestion of sisal leaf waste leachate. Process performance was investigated by increasing the organic loading rate (OLR) step-wise. The best results were obtained from the bioreactor packed with sisal fibre waste. It had the highest chemical oxygen demand (COD) removal efficiencies in the range of 80-93% at OLRs in the range of 2.4-25 g COD L-1d-1. The degradation pattern of volatile fatty acids (VFAs) showed that the degradation of propionate was limiting at higher OLRs. The stable pH and higher partial alkalinity (PA) of the outflow illustrated that packed-bed bioreactors have a good ability to withstand the variations in load and volatile fatty acid concentrations that can occur in a two-stage anaerobic process. In conclusion, sisal fibre waste was shown to be a novel promising biofilm carrier and would work very well in methanogenic biofilm bioreactors treating sisal leaf tissue waste leachate. Furthermore both sisal wastes are available in the neighbourhood of sisal industries, which makes anaerobic digestion scale up at sisal factory level feasible and cost-effective

Effects of Bladder Training and/or Tolterodine in Female Patients with Overactive Bladder Syndrome: A Prospective, Randomized Study

We compared the effects of bladder training and/or tolterodine as first line treatment in female patients with overactive bladder (OAB). One hundred and thirty-nine female patients with OAB were randomized to treatment with bladder training (BT), tolterodine (To, 2 mg twice daily) or both (Co) for 12 weeks. Treatment efficacy was measured by micturition diary, urgency scores and patients' subjective assessment of their bladder condition. Mean frequency and nocturia significantly decreased in all treatment groups, declining 25.9% and 56.1%, respectively, in the BT group; 30.2% and 65.4%, respectively, in the To group; and 33.5% and 66.3%, respectively in the Co group (p<0.05 for each). The decrease in frequency was significantly greater in the Co group than in the BT group (p<0.05). Mean urgency score decreased by 44.8%, 62.2% and 60.2% in the BT, To, and Co groups, respectively, and the improvement was significantly greater in the To and Co groups than in the BT group (p<0.05 for each). Although BT, To and their combination were all effective in controlling OAB symptoms, combination therapy was more effective than either method alone. Tolterodine alone may be instituted as a first-line therapy, but may be more effective when combined with bladder training

Microclimatological consequences for plant and microbial composition in Sphagnum-dominated peatlands

In three Scandinavian peatlands we studied to what extent plant and microbial community compositions are governed by local-scale microhabitat, with a special interest in the effect of aspect (i.e. exposition of slopes). Despite differences in solar irradiance between the south- and north-facing slopes, maximum temperature was elevated in the south-facing slopes at the most northern site only. Pore-water nutrient concentrations were not affected by aspect, yet dissolved organic carbon concentrations were higher in the south-facing microhabitats. This was likely caused by higher vascular plant biomass. Plant and microbial community composition clearly differed among sites. In all three sites, microhabitat (i.e. prevailing water-table depth) affected the plant and microbial community compositions. Aspect, however, did not affect community composition, even though microclimate significantly differed between the south- and the north-facing aspects at the northernmost site. Our results highlight the complex link between plant community composition, microbial community and environmental conditions, which deserves much more attention than currently in order to fully understand the effects of climate change on peatland ecosystem function.I