Integration of biocompatible hydrogen evolution catalyst developed from metal-mix solutions with microbial electrosynthesis.

Microbial conversion of CO2 to multi-carbon compounds such as acetate and butyrate is a promising valorisation technique. For those reactions, the electrochemical supply of hydrogen to the biocatalyst is a viable approach. Earlier we have shown that trace metals from microbial growth media spontaneously form in situ electro-catalysts for hydrogen evolution. Here, we show biocompatibility with the successful integration of such metal mix-based HER catalyst for immediate start-up of microbial acetogenesis (CO2 to acetate). Also, n-butyrate formation started fast (after twenty days). Hydrogen was always produced in excess, although productivity decreased over the 36 to 50 days, possibly due to metal leaching from the cathode. The HER catalyst boosted microbial productivity in a two-step microbial community bioprocess: acetogenesis by a BRH-c20a strain and acetate elongation to n-butyrate by Clostridium sensu stricto 12 (related) species. These findings provide new routes to integrate electro-catalysts and micro-organisms showing respectively bio and electrochemical compatibility.

Cation exchange membrane behaviour of extracellular polymeric substances (EPS) in salt adapted granular sludge.

This paper aims to elucidate the role of extracellular polymeric substances (EPS) in regulating anion and cation concentrations and toxicity towards microorganisms in anaerobic granular sludges adapted to low (0.22 M of Na+) and high salinity (0.87 M of Na+). The ion exchange properties of EPS were studied with a novel approach, where EPS were entangled with an inert binder (PVDF-HFP) to form a membrane and characterized in an electrodialysis cell. With a mixture of NaCl and KCl salts the EPS membrane was shown to act as a cation exchange membrane (CEM) with a current efficiency of ∼80%, meaning that EPS do not behave as ideal CEM. Surprisingly, the membrane had selectivity for transport of K+ compared to Na+ with a separation factor ( [Formula: see text] ) of 1.3. These properties were compared to a layer prepared from a model compound of EPS (alginate) and a commercial CEM. The alginate layer had a similar current efficiency (∼80%.), but even higher [Formula: see text] of 1.9, while the commercial CEM did not show selectivity towards K+ or Na+, but exhibited the highest current efficiency of 92%. The selectivity of EPS and alginate towards K+ transport has interesting potential applications for ion separation from water streams and should be further investigated. The anion repelling and cation binding properties of EPS in hydrated and dehydrated granules were further confirmed with microscopy (SEM-EDX, epifluorescence) and ion chromatography (ICP-OES, IC) techniques. Results of specific methanogenic activity (SMA) tests conducted with 0.22 and 0.87 M Na+ adapted granular sludges and with various monovalent salts suggested that ions which are preferentially transported by EPS are also more toxic towards methanogenic cells.

The potential of osmolytes and their precursors to alleviate osmotic stress of anaerobic granular sludge.

Increasing amounts of saline (waste)water with high concentrations of organic pollutants are generated globally. In the anaerobic (waste)water treatment domain, high salt concentrations are repeatedly reported to inhibit methanogenic activity and strategies to overcome this toxicity are needed. Current research focuses on the use of potential osmolyte precursor compounds for osmotic stress alleviation in granular anaerobic sludges upon exposure to hypersalinity shocks. Glutamic acid, aspartic acid, lysine, potassium, gelatine, and tryptone were tested for their potential to alleviate osmotic stress in laboratory grown and full - scale granular sludge. The laboratory grown granular sludge was adapted to 5 (R5) and 20 (R20) g Na+/L. Full-scale granular sludge was obtained from internal circulation reactors treating tannery (waste)water with influent conductivity of 29.2 (Do) and 14.1 (Li) mS/cm. In batch experiments which focused on specific methanogenic activity (SMA), R5 granular sludge was exposed to a hypersalinity shock of 20 g Na+/L. The granular sludge of Do and Li was exposed to a hypersalinity shock of 10 g Na+/L with sodium acetate as the sole carbon source. The effects on R20 granular sludge were studied at the salinity level to which the sludge was already adapted, namely 20 g Na+/L. Dosing of glutamic acid, aspartic acid, gelatine, and tryptone resulted in increased SMA compared to only acetate fed batches. In batches with added glutamic acid, the SMA increased by 115% (Li), 35% (Do) and 9% (R20). With added aspartic acid, SMA increased by 72% (Li), 26% (Do), 12% (R5) and 7% (R20). The addition of tryptone resulted in SMA increases of 36% (R5), 17% (R20), 179% (Li), and 48% (Do), whereas added gelatine increased the SMA by 30% (R5), 14% (R20), 23% (Li), and 13% (Do). The addition of lysine, meanwhile, gave negative effects on SMA of all tested granular sludges. Potassium at sea water Na/K ratio (27.8 w/w) had a slight positive effect on SMA of Do (7.3%) and Li (10.1%), whereas at double the sea water ratio (13.9% w/w) had no pronounced positive effect. R20 granular sludge was also exposed to hyposalinity shock from 20 down to 5 g Na+/L. Glutamate and N-acetyl-ß-lysine were excreted by microbial consortium in anaerobic granular sludge adapted to 20 g Na+/L upon this exposure to hyposalinity. A potential consequence when applying these results is that saline streams containing specific and hydrolysable proteins can be anaerobically treated without additional dosing of osmolytes.

Efficacy of methanogenic biomass acclimation in mesophilic anaerobic digestion of ultrasound pretreated sludge.

Methanogenic biomass plays a key role with regard to methane production during anaerobic bioconversion of organic substrates. In this study, the effect of two different acclimated inocula on digestion performances was investigated by means of anaerobic batch tests on untreated and sonicated waste-activated sludge. Organics solubilization and removal kinetics, the abundance and physiological conditions of archaeal cells on ultimate methane yield were evaluated. The simultaneous presence of Methanosarcina and Methanosaeta in the archaeal biomass, the higher initial archaeal cells relative abundance and their occurrence in the aggregated forms were the main factors positively affecting the conversion into methane. The presence of the acclimated inoculum at the start-up influenced positively the methane improvement due to sonication, and the methane-specific production increased from 0.335 ± 0.03 to 0.420 ± 0.05 Nm3/kg VSfed. Moreover, the better physiological state of methanogens permitted to appreciate the effect of hydrolysis improvement by ultrasound pretreatment.

Fast anaerobic sludge granulation at elevated salinity.

It is commonly accepted that high salt concentrations negatively affect microbial activity in biological wastewater treatment reactors such as upflow anaerobic sludge blanket (UASB) reactors. Microbial aggregation in such reactors is equally important. It is well documented that anaerobic granules, when exposed to high salinity become weak and disintegrate, causing wash-out, operational problems and decreasing process performance. In this research, the possibility of microbial granule formation from dispersed biomass was investigated at salinity levels of 5 and 20 g Na+/L. High removal efficiencies of soluble influent organics were achieved at both salinity levels and this was accompanied by fast and robust formation of microbial granules. The process was found to be stable for the entire operational period of 217 days. As far as we know this is the first time it has been demonstrated that stable granule formation is possible at a salinity level as high as 20 g Na+/L. Methanosaeta was identified as the dominant methanogen at both salinity levels. Streptococcus spp. and bacteria belonging to the family Lachnospiraceae were identified as the dominant microbial population at 5 and 20 and g Na+/L, respectively.

Biofilm formation and granule properties in anaerobic digestion at high salinity.

For the anaerobic biological treatment of saline wastewater, Anaerobic Digestion (AD) is currently a possibility, even though elevated salt concentrations can be a major obstacle. Anaerobic consortia and especially methanogenic archaea are very sensitive to fluctuations in salinity. When working with Upflow Sludge Blanket Reactor (UASB) technology, in which the microorganisms are aggregated and retained in the system as a granular biofilm, high sodium concentration negatively affects aggregation and consequently process performances. In this research, we analysed the structure of the biofilm and granules formed during the anaerobic treatment of high salinity (at 10 and 20 g/L of sodium) synthetic wastewater at lab scale. The acclimated inoculum was able to accomplish high rates of organics removal at all the salinity levels tested. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses identified the acetoclastic Methanosaeta harundinacea as the key player involved acetate degradation and microbial attachment/granulation. When additional calcium (1 g/L) was added to overcome the negative effect of sodium on microbial aggregation, during the biofilm formation process microbial attachment and acetate degradation decreased. The same result was observed on granules formation: while calcium had a positive effect on granules strength when added to UASB reactors, Methanosaeta filaments were not present and the degradation of the partially acidified substrate was negatively influenced. This research demonstrated the possibility to get granulation at high salinity, bringing to the forefront the importance of a selection towards Methanosaeta cells growing in filamentous form to obtain strong and healthy granules.

Liquid chromatography coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry and post-column addition of metal salt solutions as a powerful tool for the metabolic profiling of Fusarium oxysporum.

Fusarium oxysporum L11 is a non-pathogenic soil-borne fungal strain that yielded an extract that showed antifungal activity against phytopathogens. In this study, reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry (API-QTOF-MS) was applied for the comprehensive profiling of the metabolites from the extract. The employed sources were electrospray (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). Post-column addition of metal solutions of Ca, Cu and Zn(II) was also tested using ESI. A total of 137 compounds were identified or tentatively identified by matching their accurate mass signals, suggested molecular formulae and MS/MS analysis with previously reported data. Some compounds were isolated and identified by NMR. The extract was rich in cyclic peptides like cyclosporins, diketopiperazines and sansalvamides, most of which were new, and are reported here for the first time. The use of post-column addition of metals resulted in a useful strategy for the discrimination of compound classes since specific adducts were observed for the different compound families. This technique also allowed the screening for compounds with metal binding properties. Thus, the applied methodology is a useful choice for the metabolic profiling of extracts and also for the selection of metabolites with potential biological activities related to interactions with metal ions.

[What is new in 2014 for the specialist in hospital internal medicine? The point of view of university hospital chief residents]. / L'année 2014 mise en perspective par les internistes hospitaliers.

The year 2014 was rich in significant advances in all areas of internal medicine. Many of them have an impact on our daily practice and on the way we manage one problem or another. From the use of the ultrasound for the diagnosis of pneumonia to the choice of the site of venous access and the type of line, and the increasing complexity of choosing an oral anticoagulant agent, this selection offers to the readers a brief overview of the major advances. The chief residents in the Service of internal medicine of the Lausanne University hospital are pleased to share their readings.

Ecology and biotechnological potential of the thermophilic fermentative Coprothermobacter spp.

Thermophilic bacteria have been isolated from several terrestrial, marine and industrial environments. Anaerobic digesters treating organic wastes are often an important source of these microorganisms, which catalyze a wide array of metabolic processes. Moreover, organic wastes are primarily composed of proteins, whose degradation is often incomplete. Coprothermobacter spp. are proteolytic anaerobic thermophilic microbes identified in several studies focused on the analysis of the microbial community structure in anaerobic thermophilic reactors. They are currently classified in the phylum Firmicutes; nevertheless, several authors showed that the Coprothermobacter group is most closely related to the phyla Dictyoglomi and Thermotoga. Since only a few proteolytic anaerobic thermophiles have been characterized so far, this microorganism has attracted the attention of researchers for its potential applications with high-temperature environments. In addition to proteolysis, Coprothermobacter spp. showed several metabolic abilities and may have a biotechnological application either as source of thermostable enzymes or as inoculum in anaerobic processes. Moreover, they can improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea. To gain a better understanding of the phylogenesis, metabolic capabilities and adaptations of these microorganisms, it is of importance to better define the role in thermophilic environments and to disclose properties not yet investigated.

Thermophilic anaerobic digestion of thermal pretreated sludge: role of microbial community structure and correlation with process performances.

Thermal hydrolysis pretreatment coupled with Thermophilic Anaerobic Digestion (TAD) for Waste Activated Sludge (WAS) treatment is a promising combination to improve biodegradation kinetics during stabilization. However, to date there is a limited knowledge of the anaerobic biomass composition and its impact on TAD process performances. In this study, the structure and dynamics of the microbial communities selected in two semi-continuous anaerobic digesters, fed with untreated and thermal pretreated sludge, were investigated. The systems were operated for 250 days at different organic loading rate. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses allowed us to identify the majority of bacterial and archaeal populations. Proteolytic Coprothermobacter spp. and hydrogenotrophic Methanothermobacter spp. living in strict syntrophic association were found to dominate in TAD process. The establishment of a syntrophic proteolytic pathway was favoured by the high temperature of the process and enhanced by the thermal pretreatment of the feeding sludge. Proteolytic activity, alone or with thermal pretreatment, occurred during TAD as proven by increasing concentration of soluble ammonia and soluble COD (sCOD) during the process. However, the availability of a readily biodegradable substrate due to pretreatment allowed to significant sCOD removals (more than 55%) corresponding to higher biogas production in the reactor fed with thermal pretreated sludge. Microbial population dynamics analysed by FISH showed that Coprothermobacter and Methanothermobacter immediately established a stable syntrophic association in the reactor fed with pretreated sludge in line with the overall improved TAD performances observed under these conditions.

Microbial diversity in innovative mesophilic/thermophilic temperature-phased anaerobic digestion of sludge.

Anaerobic digestion (AD) is one of the few sustainable technologies that both produce energy and treat waste streams. Driven by a complex and diverse community of microbes, AD may be affected by different factors, many of which also influence the composition and activity of the microbial community. In this study, the biodiversity of microbial populations in innovative mesophilic/thermophilic temperature-phased AD of sludge was evaluated by means of fluorescence in situ hybridization (FISH). The increase of digestion temperature drastically affected the microbial composition and selected specialized biomass. Hydrogenotrophic Methanobacteriales and the protein fermentative bacterium Coprothermobacter spp. were identified in the thermophilic anaerobic biomass. Shannon-Weaver diversity (H') and evenness (E) indices were calculated using FISH data. Species richness was lower under thermophilic conditions compared with the values estimated in mesophilic samples, and it was flanked by similar trend of the evenness indicating that thermophilic communities may be therefore more susceptible to sudden changes and less prompt to adapting to operative variations.

Advanced anaerobic processes to enhance waste activated sludge stabilization.

The requirement for enhanced stabilization processes to obtain a more stable, pathogen-free sludge for agricultural use is an increasing challenge to comply with in the waste hierarchy. With this in mind, the Routes European project ('Novel processing routes for effective sewage sludge management') is addressed to assess innovative solutions with the aim of maximizing sludge quality and biological stability. In order to increase anaerobic stabilization performances, the sequential anerobic/aerobic process and the thermophilic digestion process, with or without integration of the thermal hydrolysis pre-treatment, were investigated as regards the effect on sludge stabilization, dewaterability and digestion performances. Thermal pre-treatment improved anaerobic digestion in terms of volatile solids reduction and biogas production, but digestate dewaterability worsened. Fluorescence in situ hybridization (FISH) quantification showed an increase of methanogens consistent with the increase of biogas produced. The aerobic post-treatment after mesophilic digestion had a beneficial effect on dewaterability and stability of the digested sludge even if was with a reduction of the potential energy recovery.

Hyaluronic acid scaffold for skin defects in congenital syndactyly release surgery: a novel technique based on the regenerative model.

Syndactyly release may require skin grafting to fill the skin defects, which might lead to complications or poor cosmetic outcomes. A simple graftless technique for syndactyly release with a hyaluronic acid (HA) scaffold used to cover the bare areas is described. Between 2008 and 2011, release of 26 webs in 23 patients was performed. All skin defects were covered with Hyalomatrix(®) PA. One patient was excluded due to early post-operative infection that required HA scaffold removal before its integration. Web creep, secondary deformities, scar quality, and patient and parental satisfaction were assessed. Mean follow-up of the group of 22 patients was 24 months. There were no secondary deformities and minimal degree of web creep. All patients had close to normal pigmentation and good pliability at the sites of scaffold application. The results confirm the use of a HA scaffold as a promising alternative to skin grafting in syndactyly release surgery.

Potential of high-frequency ultrasounds to improve sludge anaerobic conversion and surfactants removal at different food/inoculum ratio.

High-frequency ultrasounds have recently gained interest as oxidative technique for sonochemical degradation of organic contaminants in water. In this study an innovative approach applying 200 kHz ultrasounds to improve both sludge anaerobic biodegradability and decontamination is proposed. Digestion tests were performed on batch reactors fed either with untreated or sonicated sludge, at different food/inoculum (F/I) ratio, in the range 0.3-0.9. First order kinetic highlighted a decreasing trend of the hydrolysis rate by increasing F/I, both for untreated and sonicated sludge. Positive effect of ultrasounds on specific biogas production was evident, but the conversion rate for pretreated sludge was strongly affected by F/I, and decreased by increasing F/I. Anionic surfactants anaerobic removal occurred in all tests, but the effect of ultrasounds was significant only at F/I=0.3. By pretreating sludge with high frequency ultrasounds, low F/I was the ideal ratio improving both sludge anaerobic digestion and decontamination.

The concept of self and emotional involvement in living kidney donation: a psychometric investigation.

OBJECTIVE: The aim of our study was to analyze, from a psychological point of view, living kidney donor personality, examining a sample of 18 living kidney donors. PATIENTS AND METHODS: The personality study was performed using The Millon Clinical Multiaxial Inventory-III in 18 potential kidney donors, 6 of whom were genetically and 12 emotionally related individuals. RESULTS: Our study showed the presence of narcissistic, histrionic, and obsessive-compulsive personality traits in living kidney donors. CONCLUSIONS: It is necessary to explore the development of motivation for living donation in order to achieve and maintain a harmonious relationship with the recipient while respecting their individuality.

The study of personality in renal transplant patients: possible predictor of an adequate social adaptation?

BACKGROUND: This study explored the personality characteristic traits within a sample of renal transplant patients, seeking to obtain predictive index for likely clinical impacts. PATIENTS AND METHODS: The personality study was performed using the Structured Clinical Interview Axis II Personality Disorders for Diagnostic and Statistical Manual of Mental Disorders fourth edition, text revision in 60 recipients of kidney transplantations from deceased donors. RESULTS: The personality trait that prevailed in the female gender was borderline, while in the male gender it appeared to be predominantly obsessive-compulsive personality trait. CONCLUSIONS: The personality study proved to be a good index to predict effects on the level of social adjustment. In this way, patients who have shown pathologic personality traits can be identified early to provide adequate psychologic-psychiatric support and follow-up.

[What is new in 2012 for the specialist in hospital internal medicine?]. / L'année 2012 de la perspective de l'interniste hospitalier.

The knowledge in internal medicine is constantly and so rapidly evolving that practices have to be updated and adjusted to recent scientific rules, in order to improve quality and efficiency in the day to day activities. Residents in the Service of internal medicine of the Lausanne University present several relevant papers published in 2012, whose results are susceptible to change the daily hospital practices. From modest impacts to real revolution, a variety of subjects are discussed in the perspective of evidence based medicine.

Estrogens need insulin-like growth factor I cooperation to exert their neuroprotective effects in post-menopausal women.

BACKGROUND: The abrupt fall in estrogens levels during the menopausal transition may connote an hormonal state predisposing to neurodegenerative disorders, e.g. Alzheimer's disease (AD). Reportedly, the neurotrophic activity of estrogen involves an interaction with IGF-I. AIM: To evaluate the leukocyte gene expression of progesterone receptor (PR-A/B) and interleukin 6 (IL-6), two parameters under the control of estrogens and involved in the pathogenesis of AD. SUBJECTS: The study was conducted in non-demented women divided into two groups according to their pre- or post-menopausal state; each group being further divided into two subgroups based on their circulating levels of IGF-I (normal or low). An additional sample of AD-affected women served as a comparison group. RESULTS: Estrogens maintained their full activity only when IGF-I levels were in the range of normalcy. On the contrary, if the concentrations of one or both hormones were reduced, estrogens were not anymore capable to control the gene expression of PR-A/B or IL-6. CONCLUSIONS: Before administering hormone-based replacement therapy, characterization of the somatotropic function should be performed in the early phase of the menopause.

[Hospital-based internal medicine: year 2011 in chief resident's perspective]. / Médecine interne générale en pratique hospitalière: l'année 2011 mise en perspective par les chefs de clinique.

The year 2011 was full of significant advances in all areas of medicine. Whether small or large issues, they all have an impact on daily practice in general internal medicine. For example, intravenous administration of diuretics in heart failure shows no benefit. But double dose may improve symptoms faster. Direct Xa inhibitors are emerging as alternative to anti-vitamin K. beta-blockers reduce overall mortality in COPD and do not worsen lung function significantly. Each year, the chief residents from the Department of internal medicine at the University hospital of Lausanne meet to share their readings. Twelve new therapeutic considerations of 2011 are reviewed here.