Waste-derived volatile fatty acids as carbon source for added-value fermentation approaches

The establishment of a sustainable circular bioeconomy requires the effective material recycling from biomass and biowaste beyond composting/fertilizer or anaerobic digestion/bioenergy. Recently, volatile fatty acids attracted much attention due to their potential application as carbon source for the microbial production of high added-value products. Their low-cost production from different types of wastes through dark fermentation is a key aspect, which will potentially lead to the sustainable production of fuels, materials or chemicals, while diminishing the waste volume. This article reviews the utilization of a volatile fatty acid platform for the microbial production of polyhydroxyalkanoates, single cell oil and omega-3 fatty acids, giving emphasis on the fermentation challenges for the efficient implementation of the bioprocess and how they were addressed. These challenges were addressed through a research project funded by the European Commission under the Horizon 2020 programme entitled 'VOLATILE-Biowaste derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks'.This work was supported by the European project 'Volatile-Biowaste-derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks' and has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 720777

Waste-derived volatile fatty acids as carbon source for added-value fermentation approaches

The establishment of a sustainable circular bioeconomy requires the effective material recycling from biomass and biowaste beyond composting/fertilizer or anaerobic digestion/bioenergy. Recently, volatile fatty acids attracted much attention due to their potential application as carbon source for the microbial production of high added-value products. Their low-cost production from different types of wastes through dark fermentation is a key aspect, which will potentially lead to the sustainable production of fuels, materials or chemicals, while diminishing the waste volume. This article reviews the utilization of a volatile fatty acid platform for the microbial production of polyhydroxyalkanoates, single cell oil and omega-3 fatty acids, giving emphasis on the fermentation challenges for the efficient implementation of the bioprocess and how they were addressed. These challenges were addressed through a research project funded by the European Commission under the Horizon 2020 programme entitled ‘VOLATILE—Biowaste derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks’.This work was supported by the European project ‘VolatileBiowaste-derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks’ and has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement number 720777

Production of PHB in a cell recycling fed-batch process using Cupriavidus necator

Um einen Biokunststoff wie z.B. Polyhydroxyalkanoat zu einem konkurrenzfähigen Preis produzieren zu können, ist man bestrebt, immer billigere Substrate in der Produktion einzusetzen. Diese Substrate weisen in der Regel allerdings eine eher geringe Konzentration der Kohlenstoffquelle auf, sodass sie kaum in einem konventionellen Fed-Batch Prozesse nutzbar sind. Aus diesem Grund gilt es neue Prozesse zu entwickeln, die diese Substrate verwerten können und gleichzeitig ähnlich hohe Produktivitäten und Zelldichten wie mit konventionellen Prozessen erreichen. Im Rahmen dieser Arbeit wurde nun ein Prozess entwickelt, der dies mittels „Cell Recyclings“ erreicht. Zur Umsetzung dieses Prozesses im Labormaßstab wurden zwei verschiedene Biorekatorsysteme z.T. stark modifiziert und mit einer Hohlfasermembran zur Rückhaltung der Zellen ausgestattet. Nach experimenteller Bestimmung unterschiedlicher Prozessparameter und Fermentationsbedingungen wurde dieser Prozess in vier „Cell Recycling“ Fed-Batch Experimente getestet. Dies geschah unter Einsatz des Bakteriums Cupriavidus necator, einem natürlichen Produzenten von Polyhydroxybutyrat (PHB), dem bekanntesten Polyhydroxyalkanoat. Als Nährmedium kam ein Mineralmedium mit einer Glukosekonzentration von 50 g/L zum Einsatz. Bei diesen Experimenten konnten eine PHB Produktivität von bis zu 1.4 g/Lh und eine Zelldichte von 32.6 g/L erreicht werden. Darüber hinaus konnte in diesem Experiment in einem nur 24.3 Stunden dauernden Prozess ein sehr hoher PHB Anteil von 92 % in der getrockneten Biomasse erzielt werden. Diese Ergebnisse sind mit anderen publizierten Prozessen vergleichbar, die Daten deuten allerdings darauf hin, dass sowohl die Produktivität als auch die Ausbeute des Prozesses noch weiter gesteigert werden können, sofern der Prozess mit einer höheren Zelldichte geführt wird und man die Feed Strategie optimiert.For an economically feasible production of bioplastics such as polyhydroxyalkanoates there is an urge to use cheap substrates. Such substrates often contain only a low amount of carbon, making them impractical for the use in conventional fed-batch processes. Due to these facts, new methods have to be developed to utilize such media, while nevertheless reaching high cell densities and productivities. In this work, a novel process using Cupriavidus necator to produce polyhydroxybutyrate (PHB), the most prominent polyhydroxyalkanoate, is proposed. This process, employing cell recycling is furthermore implemented and tested at lab scale. In various experiments the influence of fermentation conditions and process parameters were studied using mineral media. Subsequently four cell recycling fed-batch fermentation experiments were done in two different modified bioreactor systems using media with a glucose concentration of 50 g/L and hollow fibre membranes. In one of those experiments a productivity of 1.4 g PHB per litre and hour could be reached while the cell dry weight reached 32.6 g/L in only 24.3 hours, and the PHB polymer made up 92% of the cell dry weight. These results are comparable to other published processes and the data further suggest that the productivities and the PHB yield of the process can even be increased by running the process at higher cell densities and further optimising the feed strategy.Lukas BurgstallerMit deutscher ZusammenfassungUniversität für Bodenkultur Wien, Masterarbeit, 2016(VLID)193549

Serious adverse events in patients with target-oriented blood pressure management: a systematic review

: On the basis of the benefits of antihypertensive treatment, progressively intensive treatment is advocated. However, it remains controversial whether intensive blood pressure control might increase the frequency of serious adverse events (SAEs) compared with moderate control. This review assessed the occurrence of SAEs in blood pressure treatment with predefined blood pressure targets. Seven original studies and eight post hoc analyses (derived from two original studies) met the inclusion criteria. Compared with moderate blood pressure treatment, intensive treatment was associated with a significant increase in treatment-related SAEs (Sign-test: P = 0.0002, Wilcoxon signed-rank test: P = 0.001). However, comparability between studies was limited, due to unclear determinations about the treatment-relatedness of adverse events, missing definitions of SAEs and variations in recording methods. Thus, a meta-analysis was not justified. The definitions of serious adverse events and methods of recording and reporting need to be improved and standardized to facilitate the comparison of results

Land-use preferences of the European green toad (Bufotes viridis) in the city of Vienna (Austria): the importance of open land in urban environments

Abstract Urban areas are increasing worldwide, which poses threats to animal wildlife. However, in certain cases cities can provide refuges for endangered animals. The European green toad (Bufotes viridis) is one of such examples, which is known from cities throughout their distribution. In contrast, considerable areas of their former (primary) habitats have been degraded. The primary habitats of this species include steppes and wild river floodplains, both characterized by dynamic changes and the presence of open areas. We used available green toad observation data (2007–2020) to model the effects of land-use types on occurrence probability in the city of Vienna. Forest and densely populated areas were highly significantly negatively associated with green toad presence, while transformation/construction site areas showed a strong positive effect. Such occurrence pattern might be characteristic for early succession species, which depend on stochastic environmental disturbances (e.g., droughts and floods) in their primary habitats. We argue that urban landscape planning should appreciate the potential ecological value of open land in cities which is either in a transition phase or a permanent ‘wasteland’. Ecological managing of such landscape could vastly increase urban biodiversity

Pilot Scale Production of Single Cell Oil by <i>Apiotrichum brassicae</i> and <i>Pichia kudriavzevii</i> from Acetic Acid and Propionic Acid

Volatile fatty acids can be used as a cheap carbon source for biotechnological lipid production with oleaginous yeasts, but one factor limiting their large-scale use is their inherent cytotoxicity. Developing a suitable cultivation strategy can help mitigate the adverse effect volatile fatty acids have, since these effects are strongly dependent on concentration and pH. This work shows that, by employing a pH-stat fed-batch approach for the cultivation of Apiotrichum brassicae V134 and Pichia kudriavzevii V194, lipid contents above 56 g/100 g dry cell weight and dry cell weight concentrations above 30 g/L can be reached. Furthermore, volumetric lipid productivities up to 0.29 g/Lh could be achieved using acetic and propionic acid as a sole carbon source. It was also demonstrated that the developed process is robust and scalable. Scale-up to the 500 L scale resulted in a similar lipid yield, dry cell weight (31–37 g/L), and single cell oil content (56 g/100 g dry cell weight–58 g/100 g dry cell weight). The main fatty acid present in the produced lipids was oleic acid (36–43%), but also odd-numbered fatty acids, especially heptadecanoic acid (7–15%), were present. Additionally, different methods for the pretreatment of biomass prior to lipid extraction were assessed, and the iodine value (48), peroxide value (7.3), and acid value (4.3) of the extracted single cell oil were determined

The European green toad, Bufotes viridis, in Donaufeld (Vienna, Austria): status and size of the population

The European green toad, Bufotes viridis (Laurenti, 1768), is a rare and protected species in Vienna. In spring and summer 2020, we conducted a survey to assess size and status of its population in Donaufeld, an agricultural area designated for real estate development. Recaptures of photographically registered toads allowed to estimate the population size with 137 individuals (confidence interval: 104–181). Comparatively large body size indicates the presence of a well-established population. Reproductive success was high in the study year. A mismatch mating of a male B. viridis with a female Bufo bufo was observed. Mitigation measures are needed to support this population facing imminent habitat deterioration

Telemetry and Accelerometer Tracking of Green Toads in an Urban Habitat: Methodological Notes and Preliminary Findings

Advancements in tracking technologies provide an increasingly important tool in animal monitoring and conservation that can describe animal spatial behavior in native habitats and uncover migratory routes that otherwise may be difficult or impossible to map. In addition, high-resolution accelerometer sensors provide powerful insights into animal activity patterns and can help to identify specific behaviors from accelerometer profiles alone. Previously, such accelerometers were restricted to larger animals due to size and mass constraints. However, recent advances make it possible to use such devices on smaller animals such as the European green toad (Bufotes viridis), the focus of our current study. We deploy custom made tracking devices, that consist of very-high-frequency transmitters and tri-axial accelerometers, to track toads in their native urban environment in Vienna (Austria). A total of nine toads were tracked, ranging from three to nine tracking days per individual during the post-breeding season period. We demonstrate that our devices could reliably monitor toad movement and activity during the observation period. Hence, we confirmed the predominantly nocturnal activity patterns and recorded low overall movement at this urban site. Accelerometer data revealed that toads exhibited brief but intense activity bursts between 10 pm and midnight, resting periods during the night and intermittent activity during the day. Positional tracking alone would have missed the major activity events as they rarely resulted in large positional displacements. This underscores the importance of and value in integrating multiple tracking sensors for studies of movement ecology. Our approach could be adapted for other amphibians or other animals with mass constraints and may become standard monitoring equipment in the near future

A Unified Approach to Analysis of Body Condition in Green Toads

Body condition is increasingly used to assess the status of populations and as a proxy for individual fitness. A common, quick and non-invasive approach is to estimate condition from the relation between body length and mass. Among the methods developed for this purpose, the Scaled Mass Index (SMI) appears best suited for comparisons among populations. We assembled data from 17 populations of European green toads (Bufotes viridis) with the aim of devising a standard formula applicable for monitoring this species. The mean value of the exponents describing length–mass allometry in these samples was 3.0047. Hence, we propose using 3 as a scaling coefficient for calculating the SMI in green toads. From the contrast of SMI values for both sexes within populations, estimated with either the population-specific or the standard coefficient, we conclude that applying the standard formula not only facilitates comparisons among populations but may also help to avoid misinterpretation of variation within populations