This letter to the editor argues that the assumption of a single value for the acetate recovery factor in carbon-13 stable isotope research for different individuals, can lead to significant errors in the outcomes of substrate utilization measurements.
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Using stable isotope techniques, this study shows that plasma free fatty acid oxidation is not impaired during exercise in non-obese type II diabetic patients.
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The data of this study indicate that the acetate recovery factor, used in stable isotope research, needs to be deteremined in every subject, under similar conditions as used for the tracer-derived determination of substrate oxidation.
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This paper descibes a study that shows that glycogen-lowering exercise, performed the evening before an exercise bout in combination with glycogen restriction leads to a reduction of the oxidation rate of ingested glucose during moderate-intensity exercise
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For the future circular economy, renewable carbon feedstocks manifest considerable promise for synthesizing sustainable and biodegradable polyhydroxyalkanoate (PHA). In this study, 16 wt% and 30 wt% PHA (cell dry weight) are respectively produced by thermophilic Caldimonas thermodepolymerans from beechwood xylan and wheat arabinoxylan as the sole carbon source. Moreover, an in silico study of the potential xylan-degrading proteins was conducted using proteome sequencing and CAZyme specialized bioinformatic tools. This study demonstrates the feasibility of utilizing complex polysaccharide substrates for PHA biosynthesis, thereby potentially eliminate additional processing steps and reducing overall production costs for sustainable plastic.
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The transition to a biobased economy necessitates utilizing renewable resources as a sustainable alternative to traditional fossil fuels. Bioconversion is a way to produce many green chemicals from renewables, e.g., biopolymers like PHAs. However, fermentation and bioconversion processes mostly rely on expensive, and highly refined pure substrates. The utilization of crude fractions from biorefineries, especially herbaceous lignocellulosic feedstocks, could significantly reduce costs. This presentation shows the microbial production of PHA from such a crude stream by a wild-type thermophilic bacterium Schlegelella thermodepolymerans [1]. Specifically, it uses crude xylose-rich fractions derived from a newly developed biorefinery process for grassy biomasses (the ALACEN process). This new stepwise mild flow-through biorefinery approach for grassy lignocellulosic biomass allows the production of various fractions: a fraction containing esterified aromatics, a monomeric xylose-rich stream, a glucose fraction, and a native-like lignin residue [2]. The crude xylose-rich fraction was free of fermentation-inhibiting compounds meaning that the bacterium S.thermodepolymerans could effectively use it for the production of one type of PHA, polyhydroxybutyrate. Almost 90% of the xylose in the refined wheat straw fraction was metabolized with simultaneous production of PHA, matching 90% of the PHA production per gram of sugars, comparable to PHA yields from commercially available xylose. In addition to xylose, S. thermodepolymerans converted oligosaccharides with a xylose backbone (xylans) into fermentable xylose, and subsequently utilized the xylose as a source for PHA production. Since the xylose-rich hydrolysates from the ALACEN process also contain some oligomeric xylose and minor hemicellulose-derived sugars, optimal valorization of the C5-fractions derived from the refinery process can be obtained using S. thermodepolymerans. This opens the way for further exploration of PHA production from C5-fractions out of a variety of herbaceous lignocellulosic biomasses using the ALACEN process combined with S. thermodepolymerans. Overall, the innovative utilization of renewable resources in fermentation technology, as shown herein, makes a solid contribution to the transition to a biobased economy.[1] W. Zhou, D.I. Colpa, H. Permentier, R.A. Offringa, L. Rohrbach, G.J.W. Euverink, J. Krooneman. Insight into polyhydroxyalkanoate (PHA) production from xylose and extracellular PHA degradation by a thermophilic Schlegelella thermodepolymerans. Resources, Conservation and Recycling 194 (2023) 107006, ISSN 0921-3449, https://doi.org/10.1016/j.resconrec.2023.107006. [2] S. Bertran-Llorens, W.Zhou. M.A.Palazzo, D.I.Colpa, G.J.W.Euverink, J.Krooneman, P.J.Deuss. ALACEN: a holistic herbaceous biomass fractionation process attaining a xylose-rich stream for direct microbial conversion to bioplastics. Submitted 2023.
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Muscle fiber-type specific expression of UCP3-protein is reported here for the firts time, using immunofluorescence microscopy
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Blue-green roofs have been utilized and studied for their enhanced water storage capacity compared to conventional roofs or extensive green roofs. Nonetheless, research about the thermal effect of blue-green roofs is lacking. The goal of this research is to study the thermal effect of blue-green roofs in order to assess their potential for shielding the indoor environment from outdoor temperature extremes (cold- and heat-waves). In this field study, we examined the differences between blue-green roofs and conventional gravel roofs from the perspective of the roof surface temperatures and the indoor temperatures in the city of Amsterdam for late 20th century buildings. Temperature sensor (iButtons) values indicate that outside surface temperatures for blue-green roofs are lower in summer and fluctuate less during the whole year than temperatures of conventional roofs. Results show that for three warm periods during summer in 2021 surface substrate temperatures peaked on average 5°C higher for gravel roofs than for blue-green roofs. Second, during both warm and cold periods, the temperature inside the water crate layer was more stable than the roof surface temperatures. During a cold period in winter, minimum water crate layer temperatures remained 3.0 o C higher than other outdoor surface temperatures. Finally, also the variation of the indoor temperature fluctuations of locations with and without blue-green roofs have been studied. Locations with blue-green roofs are less sensitive to outside air temperature changes, as daily temperature fluctuations (standard deviations) were systematically lower compared to conventional roofs for both warm and cold periods.
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Biogas plays an important role in many future renewable energy scenarios as a source of storable and easily extracted form of renewable energy. However, there remains uncertainty as to which sources of biomass can provide a net energy gain while being harvested in a sustainable, ecologically friendly manner. This study will focus on the utilization of common, naturally occurring grass species which are cut during landscape management and typically treated as a waste stream. This waste grass can be valorized through co-digestion with cow manure in a biogas production process. Through the construction of a biogas production model based on the methodology proposed by (Pierie, Moll, van Gemert, & Benders, 2012), a life cycle analysis (LCA) has been performed which determines the impacts and viability of using common grass in a digester to produce biogas. This model performs a material and energy flow analysis (MEFA) on the biogas production process and tracks several system indicators (or impact factors), including the process energy return on energy investment ((P)EROI), the ecological impact (measured in Eco Points), and the global warming potential (GWP, measured in terms of kg of CO2 equivalent). A case study was performed for the village of Hoogkerk in the north-east Netherlands, to determine the viability of producing a portion of the village’s energy requirements by biogas production using biomass waste streams (i.e. common grass and cow manure in a co-digestion process). This study concludes that biogas production from common grass can be an effective and sustainable source of energy, while reducing greenhouse gas emissions and negative environmental impacts when compared to alternate methods of energy production, such as biogas produced from maize and natural gas production.
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