Effects of partial maize silage substitution with microalgae on viscosity and biogas yields in continuous AD trials.

The microalga Acutodesmus obliquus was investigated as a feedstock in semi-continuously fed anaerobic digestion trials, where A. obliquus was co-digested with pig slurry and maize silage. Maize silage was substituted by both 10% and 20% untreated, and 20% ultrasonicated microalgae biomass on a VS (volatile solids) basis. The substitution of maize silage with 20% of either ultrasonicated and untreated microalgae led to significantly lower biogas yields, i.e., 560 dm³ kg-1 VScorr in the reference compared to 516 and 509 dm³ kg-1VScorr for untreated and ultrasonicated microalgae substitution. Further, the viscosities in the different reactors were measured at an OLR of 3.5 g VS dm-3 d-1. However, all treatments with microalgae resulted in significantly lower viscosities. While the mean viscosity reached 0.503 Pa s in the reference reactor, mean viscosities were 53% lower in reactors where maize was substituted by 20% microalgae, i.e. 0.239 Pa s, at a constant rotation speed of 30 rpm. Reactors where maize was substituted by 20% ultrasonicated microalgae had a 32% lower viscosity, for 10% microalgae substitution a decrease of 8% was measured. Decreased viscosities have beneficial effect on the bioprocess and the economy in biogas plants. Nonetheless, with regard to other parameters, no positive effect on biogas yields by partial substitution with microalgae biomass was found. The application of microalgae may be an interesting option in anaerobic digestion when fibrous or lignocellulosic substances lead to high viscosities of the digested slurries. High production costs remain the bottleneck for making microalgae an interesting feedstock.

Behaviour of doxycycline, oxytetracycline, tetracycline and flumequine during manure up-cycling for fertilizer production.

The fate of four widely used veterinary antibiotics (doxycycline, flumequine, oxytetracycline and tetracycline) during manure upcycling was investigated at laboratory and pilot scale. The pilot was operated continuously, while the laboratory scale in batch mode. Both set-ups consisted of anaerobic digestion, ammonia stripping and a solid liquid separation step. A partial nitritation anammox process was used to treat the laboratory scale effluent. In the pilot installation, pig manure as feed, natural occurring antibiotics levels were reduced by 92% for doxycycline, 88% for flumequine, 95% for oxytetracycline and 100% for tetracycline. In the laboratory scale set-up, antibiotic free sludge was used and the four substances were spiked. The input antibiotics concentration was reduced by 85% for doxycycline, 46% for flumequine, 97% for oxytetracycline and 100% for tetracycline. In both set-ups the centrifuge cake was identified as the major emission pathway for residual antibiotics. Manure upcycling, while producing fertilizers, can be considered effective in reducing the residual antibiotic load.

Nitrous oxide emissions of a mesh separated single stage deammonification reactor.

It is widely accepted that partial nitrification by ANAMMOX has the potential to become one of the key processes in wastewater treatment. However, large greenhouse gas emissions have been panobserved in many cases. A novel mesh separated reactor, developed to allow continuous operation of deammonification at smaller scale without external biomass selection, was compared to a conventional single-chamber deammonification sequencing batch reactor (SBR), where both were equally-sized pilot-scale reactors. The mesh reactor consisted of an aerated and an anoxic zone separated by a mesh. The resulting differences in the structure of the microbial community were detected by next-generation sequencing. When both systems were operated in a sequencing batch mode, both systems had comparable nitrous oxide emission factors in the range of 4% to 5% of the influent nitrogen load. A significant decrease was observed after switching from sequencing batch mode to continuous operation.

Cyanobacteria Biorefinery - Production of poly(3-hydroxybutyrate) with Synechocystis salina and utilisation of residual biomass.

This study evaluates a biorefinery concept for producing poly(3-hydroxybutyrate) (PHB) with the cyanobacterial strain Synechocystis salina. Due to this reason, pigment extraction and cell disruption were investigated as pre-treatment steps for the harvested cyanobacterial biomass. The results demonstrated that at least pigment removal was necessary to obtain PHB with processable quality (weight average molecular weight: 569-988kgmol-1, melting temperature: 177-182°C), which was comparable to heterotrophically produced PHB. The removed pigments could be utilised as additional by-products (chlorophylls 0.27-1.98mgg-1 TS, carotenoids 0.21-1.51mgg-1 TS, phycocyanin 0-127mgg-1 TS), whose concentration depended on the used nutrient source. Since the residual biomass still contained proteins (242mgg-1 TS), carbohydrates (6.1mgg-1 TS) and lipids (14mgg-1 TS), it could be used as animal feed or converted to biomethane (348 mn3 t-1VS) and fertiliser. The obtained results indicate that the combination of photoautotrophic PHB production with pigment extraction and utilisation of residual biomass offer the highest potential, since it contributes to decrease the environmental footprint of the process and because biomass could be used in a cascading way and the nutrient cycle could be closed.

New hybrid reactor concept incorporating a filter mesh for nitritation-anammox treatment of sludge return liquid.

A new approach to perform partial nitritation-anammox in a single tank was investigated. The tank incorporated a mesh (opening size 1.0 × 1.2 mm) as permeable barrier to create two distinct reaction zones (aerated and anoxic). The study reports on the operation and optimization of a 13 L laboratory scale reactor to treat sludge reject water with an NH4-N concentration of ∼750 mg·L-1. Performance throughout 250 days at increasing nitrogen loading rates is presented. The maximum loading rate applied was 1.5 kg NH4-N·m-3·d-1 at a hydraulic retention time of 12 h. Typical composition of the effluent was ∼50 mg·L-1 NH4-N; <5-10 mg·L-1 NO2-N and ∼60 mg·L-1 NO3-N. The corresponding average N removal rates were 85% for total nitrogen and 90% for NH4-N, respectively. Process control was very simple. It comprised only regulation of the aeration rate to maintain a pre-set pH (7.1) in the nitritation zone. Performance data clearly indicate that the investigated reactor configuration offers distinct advantages over currently installed processes. It demonstrated high robustness without the need for sophisticated process control. Apparently, the use of a permeable mesh to establish different reaction conditions in a single reactor provides new features of high potential.

Maximizing the production of butyric acid from food waste as a precursor for ABE-fermentation.

The current study reports on the maximization of butyric acid production from food waste using a mixed microbial fermentation. In semi-continuous fermentations the effect of three different pH values (5.5, 7.0 and 9.0), three different temperatures (37°C, 55°C and 70°C) and two levels of hydraulic retention time (HRT, 2days and 6days) on the formation of butyric acid as well as total volatile fatty acid production (tVFA) were investigated. Overall, pH5.5 provided the lowest butyric acid concentrations regardless of the temperature and the HRT. At mesophilic temperature (37°C) alkaline conditions (pH9.0) lead to a strong incline of tVFA as well as butyric acid concentration probably due to a decreased solubilization of the substrate. However, most efficient in terms of butyric acid production was the fermentation conducted at 55°C and pH7 where a butyric acid concentrations of 10.55g/L (HRT 2days) and 13.00g/L (HRT 6days) were achieved. Additional experiments at 70°C showed declining butyric acid production. Increase of the HRT from 2days to 6days provided an increment of butyric acid concentration throughout almost all experimental settings. However, regarding volumetric productivity the increase in concentration does not compensate for the bigger reactor volume required to establish a higher HRT. At pH7 and 55°C the resulting volumetric production rates were 5.27g/L∗d at a HRT 2days and only 2.17g/L∗d at a HRT of 6days.

Validation of a KHV antibody enzyme-linked immunosorbent assay (ELISA).

Koi herpesvirus (KHV) causes KHV disease (KHVD). The virus is highly contagious in carp or koi and can induce a high mortality. Latency and, in some cases, a lack of signs presents a challenge for virus detection. Appropriate immunological detection methods for anti-KHV antibodies have not yet been fully validated for KHV. Therefore, it was developed and validated an enzyme-linked immunosorbent assay (ELISA) to detect KHV antibodies. The assay was optimized with respect to plates, buffers, antigens and assay conditions. It demonstrated high diagnostic and analytical sensitivity and specificity and was particularly useful at the pond or farm levels. Considering the scale of the carp and koi industry worldwide, this assay represents an important practical tool for the indirect detection of KHV, also in the absence of clinical signs.

Processing recommendations for using low-solids digestate as nutrient solution for poly-ß-hydroxybutyrate production with Synechocystis salina.

Within the last decades, environmental pollution with persistent plastics steadily increased; therefore the production of biodegradable materials like poly-ß-hydroxybutyrate (PHB) is essential. Currently, PHB is produced with heterotrophic bacteria from crops. This leads to competition with food and feed production, which can be avoided by using photoautotrophic cyanobacteria, as Synechocystis salina, synthesizing PHB from CO2 at nutrient limitation. This study aims to increase the economic efficiency of PHB production with cyanobacteria by using nutrients from anaerobic digestate. First, growth and PHB production of S. salina in digestate fractions (supernatant and permeate, with/without precipitating agents) and dilutions thereof and then the scale-up (photobioreactor, 200 L working volume) were evaluated. With precipitated and centrifuged digestate diluted 1/3 the highest biomass (1.55gL-1) and PHB concentrations (95.4mgL-1), being 78% of those in mineral media, were achieved. In the photobioreactor-experiments biomass (1.63gL-1) and PHB concentrations (88.7mgL-1), being 79% and 72% of those in mineral medium, were reached, but in a cultivation time 10days longer than in mineral medium. The possibility to use digestate as sustainable and low cost nutrient solution for microalgae cultivation and photoautotrophic PHB production, instead of applying it on fields or processing it to achieve discharge limits, makes this application a highly valid option.

The amino-terminal domain of ORF149 of koi herpesvirus is preferentially targeted by IgM from carp populations surviving infection.

Recombinantly expressed fragments of the protein encoded by ORF149 (pORF149), a structural protein from the common- and koi-carp-infecting cyprinid herpesvirus-3 (CyHV-3) that was previously shown to be antigenic, were used to obtain evidence that its amino-terminal part contains immunodominant epitopes in fish populations that survived the infection. To obtain such evidence, nonspecific binding of carp serum tetrameric IgM had to be overcome by a novel ELISA protocol (rec2-ELISA). Rec2-ELISA involved pre-adsorption of carp sera with a heterologous recombinant fragment before incubation with pORF149 fragments and detection with anti-carp IgM monoclonal antibodies. Only in this way was it possible to distinguish between sera from uninfected and survivor carp populations. Although IgM from survivors recognised pORF149 fragments to a lesser degree than whole virus, specificity was confirmed by correlation of rec2- and CyHV-3-ELISAs, inhibition of rec2-ELISA by an excess of frgIIORF149, ELISA using IgM-capture, Western blotting, and reduction of reactivity in CyHV-3-ELISA by pre-adsorption of sera with frgIIORF149. The similarity of IgM-binding profiles between frgIORF149 (amino acid residues 42-629) and frgIIORF149 (42-159) and their reactivities with previously described anti-CyHV-3 monoclonal antibodies confirmed that most pORF149 epitopes were localised in its amino-terminal part.

The male ScreenING Study: prevalence of HPV-related genital and anal lesions in an urban cohort of HIV-positive men in Germany.

BACKGROUND: Human papillomaviruses (HPV) induce condylomata, anogenital cancers and their precursor lesions as anal or penile intraepithelial neoplasia (AIN/PIN). HIV-positive individuals have an increased risk for the development of anogenital HPV-induced lesions. OBJECTIVE: Estimation of the prevalence of HPV-related anogenital benign and malignant lesions in HIV-infected men attending a screening programme. METHODS: Four hundred HIV-positive men [98% men who have sex with men (MSM)] were enrolled in this prospective study from 2008 to 2011. All patients received an inspection of the anogenital region, digital rectal examination, high-resolution anoscopy (HRA), anal cytology, anal/penile histology if required, and HPV-typing of anal and penile swabs. RESULTS: At baseline, 75% (n = 302) of the men had abnormal anal cytological/histological results. 41% presented with low-grade (n = 164), 24% with high-grade anal dysplasia (n = 95) and two men with invasive anal cancer. 2.3% had PIN (n = 9) and one patient had penile cancer at baseline. Throughout the study period, 75% had anal dysplasia (low-grade n = 177, high-grade n = 125), 3.3% (n = 13) had PIN and two further patients developed anal cancer. Within the study period, 52.8% (n = 211) had condylomata (49% anal, 15% penile, 11% anal plus penile condylomata). At baseline, 88.5% of anal and 39.3% of penile swabs were HPV-DNA positive, and 77.8% of anal and 26.5% of penile swabs carried high-risk HPV-types. HPV16 was the most frequent HPV-type. CONCLUSION: HIV-positive MSM have a high risk for HPV-induced condylomata, (pre)malignant anogenital lesions and anogenital cancers. Screening for HPV-induced dysplasia is crucial to avoid progression to invasive carcinomas. Additionally, HPV-vaccination recommendations should be extended to high-risk populations.

Occurrence of human-associated Bacteroidetes genetic source tracking markers in raw and treated wastewater of municipal and domestic origin and comparison to standard and alternative indicators of faecal pollution.

This was a detailed investigation of the seasonal occurrence, dynamics, removal and resistance of human-associated genetic Bacteroidetes faecal markers (GeBaM) compared with ISO-based standard faecal indicator bacteria (SFIB), human-specific viral faecal markers and one human-associated Bacteroidetes phage in raw and treated wastewater of municipal and domestic origin. Characteristics of the selected activated sludge wastewater treatment plants (WWTPs) from Austria and Germany were studied in detail (WWTPs, n = 13, connected populations from 3 to 49000 individuals), supported by volume-proportional automated 24-h sampling and chemical water quality analysis. GeBaM were consistently detected in high concentrations in raw (median log10 8.6 marker equivalents (ME) 100 ml(-1)) and biologically treated wastewater samples (median log10 6.2-6.5 ME 100 ml(-1)), irrespective of plant size, type and time of the season (n = 53-65). GeBaM, Escherichia coli, and enterococci concentrations revealed the same range of statistical variability for raw (multiplicative standard deviations s* = 2.3-3.0) and treated wastewater (s* = 3.7-4.5), with increased variability after treatment. Clostridium perfringens spores revealed the lowest variability for raw wastewater (s* = 1.5). In raw wastewater correlations among microbiological parameters were only detectable between GeBaM, C. perfringens and JC polyomaviruses. Statistical associations amongst microbial parameters increased during wastewater treatment. Two plants with advanced treatment were also investigated, revealing a minimum log10 5.0 (10th percentile) reduction of GeBaM in the activated sludge membrane bioreactor, but no reduction of the genetic markers during UV irradiation (254 nm). This study highlights the potential of human-associated GeBaM to complement wastewater impact monitoring based on the determination of SFIB. In addition, human-specific JC polyomaviruses and adenoviruses seem to be a valuable support if highly specific markers are needed.

Influence of the gas composition on the efficiency of ammonia stripping of biogas digestate.

Impact of strip gas composition on side stream ammonia stripping, a technology aiming at the reduction of high ammonia levels in anaerobic reactors, was investigated. Evaluation of the effect of oxygen contact during air stripping showed a distinct, though lower than perceived, inhibition of anaerobic microflora. To circumvent, the feasibility and possible constraints of biogas and flue gas as alternatives in side stream stripping were studied. Experiments, with ammonia bicarbonate model solution and digestate, were conducted. It was demonstrated that the stripping performance is negatively correlated to the CO2 level in the strip gas with a progressive performance loss towards higher concentrations. In contrast to biogas with its high CO2 content, the efficiency reduction observed for flue gas was significantly less pronounced. The later provides the additional benefit that its high thermal energy can be re-utilized in the stripping unit and it is therefore considered a viable alternative for air.

Asymptomatic anal sexually transmitted infections in HIV-positive men attending anal cancer screening.

BACKGROUND: HIV-positive men who have sex with men (HIV+MSM) have an increased risk for anal dysplasia and for sexually transmitted infections (STIs). OBJECTIVES: We determined the positivity rates of Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), Mycoplasma genitalium (MG) and syphilis in HIV+MSM participating in an anal cancer screening programme. METHODS: In total, 852 intra-anal swabs were collected from 503 HIV+MSM between 2012 and 2014. Anal cytology and polymerase chain reaction assays for human papillomavirus (HPV), CT, NG and MG detection were performed. The syphilis status was determined serologically. Risk factors for STIs were explored by multiple logistic regression analysis. RESULTS: In total 20·7% (104 of 503) of the patients had an STI other than HPV within the study period. The most common was CT, found in 10·9%, followed by NG (8·9%) and MG (4·2%). Early syphilis was detected in 4·6% and past syphilis in 44·5% of the HIV+MSM. Eighteen patients (3·6%) had more than one STI episode, and 90·6% of the 127 cases of STIs were asymptomatic. Age, anal HPV infection, abnormal anal cytology and previous syphilis were risk factors for STI. CONCLUSIONS: Anal STIs are frequent and mostly asymptomatic in HIV+MSM participating in anal cancer screening. STI screening should be incorporated into anal cancer screening programmes for HIV+MSM.

Codeine Ultra-rapid Metabolizers: Age Appears to be a Key Factor in Adverse Effects of Codeine.

Codeine is widely used as an analgesic drug. Taking into account the high consumption of codeine, only few fatal adverse events have been published. A number of reports, where neonates and children showed serious or fatal adverse reactions, led to a restriction of the use of codeine in this patient group. Therefore, we reviewed the safety of codeine in adults. PubMed was systematically searched for clinical studies and case reports, with a special focus on CYP2D6, the enzyme that converts codeine to morphine and exhibits genetic polymorphism.181 cases were identified in adults in conjunction with serious or lethal effects of codeine. In the vast majority of cases, codeine was used in combination with other drugs by drug-dependent individuals or with a suicidal intent. Only 2 cases were found where ultra-rapid metabolizers experienced severe non-lethal adverse events. This is far less than would be predicted from the number of cases reported in children. The discrepancy may be explained by developmental changes in the disposition of codeine.The strategy of regulatory authorities to restrict access to codeine for infants and young children, the apparent highest risk group, has a factual and pharmacological rationale. By the same standards, there is no need for restrictions for adult use of codeine.

Improvement of anaerobic digestion performance by continuous nitrogen removal with a membrane contactor treating a substrate rich in ammonia and sulfide.

The effect of reduced ammonia levels on anaerobic digestion was investigated. Two reactors were fed with slaughterhouse waste, one with a hollow fiber membrane contractor for ammonia removal and one without. Different organic loading rates (OLR) and free ammonia and sulfide concentrations were investigated. In the reactor with the membrane contactor, the NH4-N concentration was reduced threefold. At a moderate OLR (3.1 kg chemical oxygen demand - COD/m(3)/d), this reactor performed significantly better than the reference reactor. At high OLR (4.2 kg COD/m(3)/d), the reference reactor almost stopped producing methane (0.01 Nl/gCOD). The membrane reactor also showed a stable process with a methane yield of 0.23 Nl/g COD was achieved. Both reactors had predominantly a hydrogenotrophic microbial consortium, however in the membrane reactor the genus Methanosaeta (acetoclastic) was also detected. In general, all relevant parameters and the methanogenic consortium indicated improved anaerobic digestion of the reactor with the membrane.

Assessment of the state of the art of technologies for the processing of digestate residue from anaerobic digesters.

Anaerobic digestion is widely used as an important source of renewable energy. With the increasing number and capacity of biogas plants also, adequate treatment technologies for whole digestate - the residue from anaerobic digestion - are gaining attention. In this study the state of the art of digestate processing is analysed, and currently used treatment schemes and the various technological processes involved are evaluated. The study combines data and experiences from existing large-scale digestate processing facilities in Austria, Germany, Switzerland and Italy, as well as know-how from technology providers and relevant research projects. However, the field of digestate processing is still quite new and little detailed information about the performance of different technologies at industrial scale is available. Digestate processing is gaining importance since digestate utilisation can become an important bottleneck when increasing biogas production. In addition, the production of renewable fertiliser from digestate is increasingly of interest to replace fossil fertilisers. This study is the first profound attempt to establish an assessment of the state-of-the-art technologies in use.

Anaerobic digestion of stillage fractions - estimation of the potential for energy recovery in bioethanol plants.

Stillage processing can require more than one third of the thermal energy demand of a dry-grind bioethanol production plant. Therefore, for every stillage fraction occurring in stillage processing the potential of energy recovery by anaerobic digestion (AD) was estimated. In the case of whole stillage up to 128% of the thermal energy demand in the process can be provided, so even an energetically self-sufficient bioethanol production process is possible. For wet cake the recovery potential of thermal energy is 57%, for thin stillage 41%, for syrup 40% and for the evaporation condensate 2.5%. Specific issues for establishing AD of stillage fractions are evaluated in detail; these are high nitrogen concentrations, digestate treatment and trace element supply. If animal feed is co-produced at the bioethanol plant and digestate fractions are to be reused as process water, a sufficient quality is necessary. Most interesting stillage fractions as substrates for AD are whole stillage, thin stillage and the evaporation condensate. For these fractions process details are presented.

Counteracting ammonia inhibition in anaerobic digestion by removal with a hollow fiber membrane contactor.

The aim of the current study was to investigate the feasibility of membrane contactors for continuous ammonia (NH3-N) removal in an anaerobic digestion process and to counteract ammonia inhibition. Two laboratory anaerobic digesters were fed slaughterhouse wastes with ammonium (NH4⁺) concentrations ranging from 6 to 7.4 g/L. One reactor was used as reference reactor without any ammonia removal. In the second reactor, a hollow fiber membrane contactor module was used for continuous ammonia removal. The hollow fiber membranes were directly submerged into the digestate of the anaerobic reactor. Sulfuric acid was circulated in the lumen as an adsorbent solution. Using this set up, the NH4⁺-N concentration in the membrane reactor was significantly reduced. Moreover the extraction of ammonia lowered the pH by 0.2 units. In combination that led to a lowering of the free NH3-N concentration by about 70%. Ammonia inhibition in the reference reactor was observed when the concentration exceeded 6 g/L NH4⁺-N or 1-1.2 g/L NH3-N. In contrast, in the membrane reactor the volatile fatty acid concentration, an indicator for process stability, was much lower and a higher gas yield and better degradation was observed. The chosen approach offers an appealing technology to remove ammonia directly from media having high concentrations of solids and it can help to improve process efficiency in anaerobic digestion of ammonia rich substrates.

Effects of pioglitazone versus simvastatin on biomarkers of inflammation in patients on high cardiovascular risk.

High levels of fetuin-A has been linked to cardiovascular disease, possibly via modulating low-grade systemic inflammation. We performed a subanalysis from the PIOSTAT study to investigate a possible link between fetuin-A and the inflammatory biomarker hs-CRP. 66 nondiabetic individuals at cardiovascular risk were randomized to either pioglitazone, simvastatin, or the combination of both, and followed for 12 weeks. At study endpoint, correlations between serum fetuin-A, hs-CRP, blood lipids, PAI-1, MMP-9, HOMA-IR, and liver transaminases were investigated by Spearman rank correlation. Changes in fetuin-A concentration did not correlate to changes in hs-CRP (r=0.19, p=0.16). A positive correlation was found for change of HOMA-IR value (r=0.33, p=0.01) and for the AST/ALT ratio (p<0.05). Our data suggest that the previously observed correlation between elevated circulating fetuin-A and hs-CRP in epidemiological studies may not reflect a causal relationship in nondiabetic patients on high cardiovascular risk.