91 results
Search Results
Now showing 1 - 10 of 91
- ItemAssessing the organic fraction of municipal solid wastes for the production of lactic acid(Amsterdam [u.a.] : Elsevier, 2019) López-Gómez, J. Pablo; Latorre-Sánchez, Marcos; Unger, Peter; Schneider, Roland; Coll Lozano, Caterina; Venus, JoachimWith an estimated yearly production of about 140 Mt in the EU, conventionally, the organic fraction of municipal solid wastes (OFMSW) has been disposed in landfills with negative environmental effects. Nonetheless, the chemical composition of this residue make it a substrate with great bioconversion potential. In this study, OFMSW from Spanish municipal treatment plants, were evaluated for the production of LA. Samples were identified according to the sorting mechanisms employed for their collection in: (A) separately collected, (B) non-separately collected and (C) separately collected+paper/cardboard. Enzymatic hydrolysis was used to produce hydrolysates A, B and C accordingly. Hydrolysate A showed the highest total sugars and glucose content with values of 70 and 55 g·L−1, respectively. Following the characterisation, a screening showed that growth of B. coagulans was possible in all three hydrolysates. Furthermore, lab scale fermentations showed that LA final concentrations could reach around 60 g·L−1, with yields from total sugars of above 0.60 g·g−1. A technical scale fermentation of the hydrolysate A resulted in a final LA concentration of 60.7 g·L−1, a yield of 0.71 g·g−1 with a productivity of 2.68 g·L−1·h−1. Overall, it was estimated that 0.23 g of LA could be produced from one g of dry OFMSW.
- ItemOpinion paper : Measuring livestock robustness and resilience : are we on the right track?(Amsterdam : Elsevier, 2019) Llonch, P.; Hoffmann, G.; Bodas, R.; Mirbach, D.; Verwer, C.; Haskell, M.J.[No abstract available]
- ItemEvaluating the potential of dietary crude protein manipulation in reducing ammonia emissions from cattle and pig manure: A meta-analysis(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2017-11-22) Sajeev, Erangu Purath Mohankumar; Amon, Barbara; Ammon, Christian; Zollitsch, Werner; Winiwarter, WilfriedDietary manipulation of animal diets by reducing crude protein (CP) intake is a strategic NH3 abatement option as it reduces the overall nitrogen input at the very beginning of the manure management chain. This study presents a comprehensive meta-analysis of scientific literature on NH3 reductions following a reduction of CP in cattle and pig diets. Results indicate higher mean NH3 reductions of 17 ± 6% per %-point CP reduction for cattle as compared to 11 ± 6% for pigs. Variability in NH3 emission reduction estimates reported for different manure management stages and pig categories did not indicate a significant influence. Statistically significant relationships exist between CP reduction, NH3 emissions and total ammoniacal nitrogen content in manure for both pigs and cattle, with cattle revealing higher NH3 reductions and a clearer trend in relationships. This is attributed to the greater attention given to feed optimization in pigs relative to cattle and also due to the specific physiology of ruminants to efficiently recycle nitrogen in situations of low protein intake. The higher NH3 reductions in cattle highlights the opportunity to extend concepts of feed optimization from pigs and poultry to cattle production systems to further reduce NH3 emissions from livestock manure. The results presented help to accurately quantify the effects of NH3 abatement following reduced CP levels in animal diets distinguishing between animal types and other physiological factors. This is useful in the development of emission factors associated with reduced CP as an NH3 abatement option. © 2017, The Author(s).
- ItemReducing conditions favor magnetosome production in magnetospirillum magneticum AMB-1(Lausanne : Frontiers Media, 2019) Olszewska-Widdrat, Agata; Schiro, Gabriele; Reichel, Victoria E.; Faivre, DamienMagnetotactic bacteria (MTB) are a heterogeneous group of Gram-negative prokaryotes, which all produce special magnetic organelles called magnetosomes. The magnetosome consists of a magnetic nanoparticle, either magnetite (Fe3O4) or greigite (Fe3S4), embedded in a membrane, which renders the systems colloidaly stable, a desirable property for biotechnological applications. Although these bacteria are able to regulate the formation of magnetosomes through a biologically-controlled mechanism, the environment in general and the physico-chemical conditions surrounding the cells in particular also influence biomineralization. This work thus aims at understanding how such external conditions, in particular the extracellular oxidation reduction potential, influence magnetite formation in the strain Magnetospirillum magneticum AMB-1. Controlled cultivation of the microorganisms was performed at different redox potential in a bioreactor and the formation of magnetosomes was assessed by microscopic and spectroscopic techniques. Our results show that the formation of magnetosomes is inhibited at the highest potential tested (0 mV), whereas biomineralization is facilitated under reduced conditions (-500 mV). This result improves the understanding of the biomineralization process in MTB and provides useful information in sight of a large scale production of magnetosomes for different applications. © 2019 Olszewska-Widdrat, Schiro, Reichel and Faivre.
- ItemSynergistic use of peat and charred material in growing media–an option to reduce the pressure on peatlands?(Vilnius : Technika, 2017) Kern, Jürgen; Tammeorg, Priit; Shanskiy, Merrit; Sakrabani, Ruben; Knicker, Heike; Kammann, Claudia; Tuhkanen, Eeva-Maria; Smidt, Geerd; Prasad, Munoo; Tiilikkala, Kari; Sohi, Saran; Gascó, Gabriel; Steiner, Christoph; Glaser, BrunoPeat is used as a high quality substrate for growing media in horticulture. However, unsustainable peat extraction damages peatland ecosystems, which disappeared to a large extent in Central and South Europe. Furthermore, disturbed peatlands are becoming a source of greenhouse gases due to drainage and excavation. This study is the result of a workshop within the EU COST Action TD1107 (Biochar as option for sustainable resource management), held in Tartu (Estonia) in 2015. The view of stakeholders were consulted on new biochar-based growing media and to what extent peat may be replaced in growing media by new compounds like carbonaceous materials from thermochemical conversion. First positive results from laboratory and greenhouse experiments have been reported with biochar content in growing media ranging up to 50%. Various companies have already started to use biochar as an additive in their growing media formulations. Biochar might play a more important role in replacing peat in growing media, when biochar is available, meets the quality requirements, and their use is economically feasible. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].
- ItemSensor-based detection of the severity of hyperkeratosis in the teats of dairy cows(Basel : MDPI AG, 2018) Demba, S.; Hoffmann, G.; Ammon, C.; Rose-Meierhöfer, S.The aim of this study was to evaluate whether the severity of hyperkeratosis (HK) in the teats of dairy cows can be assessed by a dielectric measurement. The study focused on surveying the occurrence of hyperkeratosis in a total of 241 teats of lactating dairy cows. A scoring system consisting of four categories was used to macroscopically assess the severity of HK. Additionally, the dielectric constant (DC) of all teats with milkability was measured in a double iteration with the MoistureMeterD (Delfin Technologies, Kuopio, Finland) on four different days. The Spearman rank correlation coefficient revealed a negative correlation between the DC and HK score (rs = −0.55 to −0.36). The results of the regression analysis showed that the DC values differed significantly between healthy teat ends (≤2) and teat ends with HK (≥3). Thus, the non-invasive measurement of DC provides a promising method of objectively assessing the occurrence and severity of HK.
- ItemUncertainty in the measurement of indoor temperature and humidity in naturally ventilated dairy buildings as influenced by measurement technique and data variability(Amsterdam : Elsevier, 2017) Hempel, Sabrina; König, Marcel; Menz, Christoph; Janke, David; Amon, Barbara; Banhazi, Thomas M.; Estellés, Fernando; Amon, ThomasThe microclimatic conditions in dairy buildings affect animal welfare and gaseous emissions. Measurements are highly variable due to the inhomogeneous distribution of heat and humidity sources (related to farm management) and the turbulent inflow (associated with meteorologic boundary conditions). The selection of the measurement strategy (number and position of the sensors) and the analysis methodology adds to the uncertainty of the applied measurement technique. To assess the suitability of different sensor positions, in situations where monitoring in the direct vicinity of the animals is not possible, we collected long-term data in two naturally ventilated dairy barns in Germany between March 2015 and April 2016 (horizontal and vertical profiles with 10 to 5 min temporal resolution). Uncertainties related to the measurement setup were assessed by comparing the device outputs under lab conditions after the on-farm experiments. We found out that the uncertainty in measurements of relative humidity is of particular importance when assessing heat stress risk and resulting economic losses in terms of temperature-humidity index. Measurements at a height of approximately 3 m–3.5 m turned out to be a good approximation for the microclimatic conditions in the animal occupied zone (including the air volume close to the emission active zone). However, further investigation along this cross-section is required to reduce uncertainties related to the inhomogeneous distribution of humidity. In addition, a regular sound cleaning (and if possible recalibration after few months) of the measurement devices is crucial to reduce the instrumentation uncertainty in long-term monitoring of relative humidity in dairy barns. © 2017 The Authors
- ItemPrediction of the biogas production using GA and ACO input features selection method for ANN model(Amsterdam [u.a.] : Elsevier, 2019) Beltramo, Tanja; Klocke, Michael; Hitzmann, BerndThis paper presents a fast and reliable approach to analyze the biogas production process with respect to the biogas production rate. The experimental data used for the developed models included 15 process variables measured at an agricultural biogas plant in Germany. In this context, the concentration of volatile fatty acids, total solids, volatile solids acid detergent fibre, acid detergent lignin, neutral detergent fibre, ammonium nitrogen, hydraulic retention time, and organic loading rate were used. Artificial neural networks (ANN) were established to predict the biogas production rate. An ant colony optimization and genetic algorithms were implemented to perform the variable selection. They identified the significant process variables, reduced the model dimension and improved the prediction capacity of the ANN models. The best prediction of the biogas production rate was obtained with an error of prediction of 6.24% and a coefficient of determination of R2 = 0.9.
- ItemComplete Genome Sequence of a New Ruminococcaceae Bacterium Isolated from Anaerobic Biomass Hydrolysis(Washington, DC : American Soc. for Microbiology, 2018) Hahnke, Sarah; Abendroth, Christian; Langer, Thomas; Codoñer, Francisco M.; Ramm, Patrice; Porcar, Manuel; Luschnig, Olaf; Klocke, MichaelA new Ruminococcaceae bacterium, strain HV4-5-B5C, participating in the anaerobic digestion of grass, was isolated from a mesophilic two-stage laboratoryscale leach bed biogas system. The draft annotated genome sequence presented in this study and 16S rRNA gene sequence analysis indicated the affiliation of HV4-5- B5C with the family Ruminococcaceae outside recently described genera. © 2018 Hahnke et al.
- ItemRepresentativeness of European biochar research: part II–pot and laboratory studies(Vilnius : Technika, 2017) Sakrabani, Ruben; Kern, Jürgen; Mankasingh, Utra; Zavalloni, Costanza; Zanchettin, Giulia; Bastos, Ana Catarina; Tammeorg, Priit; Jeffery, Simon; Glaser, Bruno; Verheijen, Frank G. A.Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps. © 2017 The Author(s) Published by VGTU Press and Informa UK Limited, [trading as Taylor & Francis Group].