\u3cem\u3eLaunching through the Surf\u3c/em\u3e Traveling Exhibit Panel 10: Fiberglassing and Painting a Dory

Panel 10 documents the process of fiberglassing and painting (gelcoating) a new wooden dory. During the spring of 2012, project collaborator Tyrone Marshall photographed Pacific City glasser Jim Allen as he fiberglassed dory number 82, the Rehab.https://digitalcommons.linfield.edu/dory_exhibit/1009/thumbnail.jp

A turn propensity scale for transmembrane helices.

Using a model protein with a 40 residue hydrophobic transmembrane segment, we have measured the ability of all the 20 naturally occurring amino acids to form a tight turn when placed in the middle of the hydrophobic segment. Turn propensities in a transmembrane helix are found to be markedly different from those of globular proteins, and in most cases correlate closely with the hydrophobicity of the residue. The turn propensity scale may be used to improve current methods for membrane protein topology prediction

Turns in transmembrane helices – determination of the minimal length of a “helical hairpin” and derivation of a fine-grained turn propensity scale

We have recently reported a first experimental turn propensity scale for transmembrane helices. This scale was derived from measurements of how efficiently a given residue placed in the middle of a 40 residue poly(Leu) stretch induces the formation of a "helical hairpin" with two rather than one transmembrane segment. We have now extended these studies, and have determined the minimum length of a poly(Leu) stretch compatible with the formation of a helical hairpin. We have also derived a more fine-grained turn propensity scale by (i) introducing each of the 20 amino acid residues into the middle of the shortest poly(Leu) stretch compatible with helical hairpin formation, and (ii) introducing pairs of residues in the middle of the 40 residue poly(Leu) stretch. The new turn propensities are consistent with the amino acid frequencies found in short hairpin loops in membrane proteins of known 3D structure

Membrane topology of the 60 kDa Oxa1p-homologue from Escherichia coli

We have characterized the membrane topology of a 60-kDa inner membrane protein from Escherichia coli that is homologous to the recently identified Oxa1p protein in Saccharomyces cerevisiae mitochondria implicated in the assembly of mitochondrial inner membrane proteins. Hydrophobicity and alkaline phosphatase fusion analyses suggest a membrane topology with six transmembrane segments, including an N-terminal signal-anchor sequence not present in mitochondrial Oxa1p. In contrast to partial N-terminal fusion protein constructs, the full-length protein folds into a protease-resistant conformation, suggesting that important folding determinants are present in the C-terminal part of the molecule

Carbon nanomaterials for electrode modification in CH4-producing bioelectrochemical systems

Introduction: Unprecedented environmental phenomena have led to emerging and challenging plans to tackle global threats for the humanity namely intensive use of fossil resources and global warming. CO2 emission to the atmosphere is one of the major driver of global climate change. In this context, the development of alternative technologies for carbon capture and utilization has attracting more and more attention. Electrochemically assisted CO2 conversion in bioelectrochemical systems (BESs) for CH4 production is a new and emerging technology. This innovative approach allows the storage of electrical renewable energy in the form of CH4 that can, when needed, be reconverted, but also the simultaneous CO2 capture contributing to mitigate the climate change and the global warming. However, this technology has limitations mainly related to the electrons transference between the electrode and the biocatalysts. Previous results, obtained within the research group, demonstrated that it is possible to increase the efficiency of the process by improving the electrode surface area which, in turn, improved the microbial attachment. Methodology: This work aimed to investigate the effect of the presence of carbon nanomaterials (carbon nanotubes (CNTs)) at the cathode, on the CH4 production via CO2 reduction. It was hypothesized that the presence of carbon nanomaterials will improve the electrode surface area, thus increasing the electron transfer between the electrode and the biocatalysts. The production of CH4 was analyzed in two BESs, one working with a modified electrode (BES-CNT) and another one that works as a control with a non-modified electrode (BES-CTRL). The potential of CNTs to improve CH4 production was investigated under different electrochemical control modes, potentiostatic and galvanostatic. In addition, the microbial community developed at the biocathode was also investigated. Results: The results demonstrated that for both electrochemical control modes, the production of CH4 was higher in the presence of CNTs compared to the control assay. The study of the microbial community developed at the biocathode under galvanostatic control demonstrated a clear enrichment of methanogens compared to the initial inoculum, however no significant differences were observed between both BES. Conclusions: In conclusion, this work contributed with preliminary insights on the effect of carbon nanomaterials, namely CNTs, to improve the biocathode performance on BESs for CH4 production from CO2.This study was supported by the Portuguese Foundation for Science and Technology(FCT) under the scope of the strategic funding of UIDB/04469/2020 unit.info:eu-repo/semantics/publishedVersio

Microbial acclimation to concentrated human urine in Bio-electrochemical system

The aim of this study is to promote the gradual acclimation of bioelectroactive microorganisms in BES to concentrated human urine, and to assess different anode potentials and carbon materials in Microbial Electrolysis Cells (MEC). Human urine is highly concentrated in nutrients, representing more than 80% of the total N load and around 45% of the total P load in municipal wastewater. Separation of urine from other wastewater streams is an interesting option to keep these valuable nutrients concentrated, in order to develop a suitable nutrient recovery concept. This work is integrated in the Value from Urine (VFU) concept, where phosphate is recovered from source segregated human urine through struvite precipitation and ammonia is recovered in a Bio-electrochemical System (BES). Enrichment of an anaerobic sludge community in urine-degrading-electroactive microorganisms was promoted in an Microbial Fuel Cell (MFC) operated with increasing concentrations of real human urine (after phosphorous removal, as struvite). This acclimated electroactive biofilm was used to inoculate the anode of MECs, aiming at H2 and ammonia production in the cathode compartment. Different carbon modified anodes and defined anode potentials were assessed in terms of performance and microbial diversity of the developed electroactive biofilms

Bioelectrochemically-assisted recovery of valuable resources from urine

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Source separated urine is highly concentrated in nutrients and biodegradable compounds. This work explores the potential of combining nutrient recovery from urine with simultaneous energy production in bioelectrochemical systems (BES), under the FP7 project "ValueFromUrine". Non-spontaneous phosphorus (P) recovery by struvite precipitation was analysed by adding three different magnesium (Mg) sources (magnesium chloride (MgCl2), magnesium hydroxide (Mg(OH)2) and magnesium oxide (MgO)). A statistical design of experiments was used to evaluate the effect of Mg:P molar ratio (1:1, 1.5:1 and 2:1) combined with stirring speed (30, 45 and 60 rpm) for each Mg source tested. MgO at 2:1 molar ratio and a stirring speed of 30 rpm allowed to achieve the highest P recovery efficiency (99 %) with struvite crystals size of 50 to 100 μm [1]. Urine obtained after P recovery, showed high concentration of biodegradable compounds being subsequently fed as substrate in a microbial fuel cell (MFC). Microbial acclimation to urine was performed in a MFC resulting in an anaerobic community successfully enriched in “urine-degrading” electroactive microorganisms. When compared to the control assay operated without preliminary microbial enrichment (81±9 mA m-2), the acclimation method achieved significantly higher current density (455 mA m-2) (p<0.05). Tissierella and Paenibacillus were the dominant genus identified in the adapted microbial community. Tissierella can convert creatinine to acetate, whereas bacterial species belonging to the Paenibacillus genus are known to function as exoelectrogens. Corynebacterium that comprise urea-hydrolysing bacteria was also detected in the developed biofilms. [...]info:eu-repo/semantics/publishedVersio

An innovative bioelectrochemical system for the recovery of phosphorus, ammonia and electricity from urine

Ammonium and phosphate fertilizers are needed in agriculture to ensure a sufficient food production. The recovery of valuable nutrients (ammonium and phosphate) from waste(water) streams will help to overcome future shortages and reduce the need for phosphorous ore imports and energy intensive ammonia production. One person produces on average 1.5 L of urine per day, which contains about 9.1 g N /L and 1 g P /L. Urine contributes about 80% of the N load and 50% of the P load in conventional domestic wastewaters. These high nutrient concentrations in urine make it possible to develop more effective and energy efficient recovery technologies. In the ValueFromUrine project the phosphorus recovery will be performed by struvite precipitation from hydrolyzed urine and the resulting effluent will be used for ammonium recovery and simultaneously electricity generation in Bioelectrochemical systems. Bioelectrochemical systems (ie Microbial Fuel Cells) are engineered systems in which bacteria catalyze the oxidation of organic substrates and transfer electrons to anode and at the cathode oxygen is reduced. The aim of our project is to develop, demonstrate and evaluate an effective energy-efficient system for the recovery of nutrients from urine. Our treatment system will be able to recover >95% of the phosphorous (as struvite) and nitrogen (as struvite and ammonia / ammonium sulphate) while producing energy. These products can substitute salts used by the chemical industry, the artificial fertilizer industry and the agricultural sector which are currently obtained in a non-renewable and unsustainable wa