Genome scale model reconstruction of the methylotrophic yeast Ogataea polymorpha

Ogataea polymorpha is a thermotolerant, methylotrophic yeast with significant industrial applications. It is a promising host to generate platform chemicals from methanol, derived e.g. from carbon capture and utilization streams. Full development of the organism into a production strain requires additional strain design, supported by metabolic modeling on the basis of a genome-scale metabolic model. However, to date, no genome-scale metabolic model is available for O. polymorpha. To overcome this limitation, we used a published reconstruction of the closely related yeast Pichia pastoris as reference and corrected reactions based on KEGG annotations. Additionally, we conducted phenotype microarray experiments to test O. polymorpha’s metabolic capabilities to grown on or respire 192 different carbon sources. Over three-quarter of the substrate usage was correctly reproduced by the model. However, O. polymorpha failed to metabolize eight substrates and gained 38 new substrates compared to the P. pastoris reference model. To enable the usage of these compounds, metabolic pathways were inferred from literature and database searches and potential enzymes and genes assigned by conducting BLAST searches. To facilitate strain engineering and identify beneficial mutants, gene-protein-reaction relationships need to be included in the model. Again, we used the P. pastoris model as reference to extend the O. polymorpha model with this relevant information. The final metabolic model of O. polymorpha supports the engineering of synthetic metabolic capabilities and enabling the optimization of production processes, thereby supporting a sustainable future methanol econom

Heat Dissipation in Variable Underground Power Cable Beddings: Experiences from a Real Scale Field Experiment

To prevent accelerated thermal aging or insulation faults in cable systems due to overheating, the current carrying capacity is usually limited by specific conductor temperatures. As the heat produced during the operation of underground cables has to be dissipated to the environment, the actual current carrying capacity of a power cable system is primarily dependent on the thermal properties of the surrounding porous bedding material and soil. To investigate the heat dissipation processes around buried power cables of real scale and with realistic electric loading, a field experiment consisting of a main field with various cable configurations, laid in four different bedding materials, and a side field with additional cable trenches for thermally enhanced bedding materials and protection pipe systems was planned and constructed. The experimental results present the strong influences of the different bedding materials on the maximum cable ampacity. Alongside the importance of the basic thermal properties, the influence of the bedding’s hydraulic properties, especially on the drying and rewetting effects, were observed. Furthermore, an increase in ampacity between 25% and 35% was determined for a cable system in a duct filled with an artificial grouting material compared to a common air-filled ducted system

Supplementary Information to ‘Experiment for Validation of Numerical Models of Coupled Heat and Mass Transfer around Energy Cables'

The increasing decentralization of electrical energy production as well as an increasing number of fluctuating regenerative energy sources require significant investments in grid expansion. Among other assessments, an exact prediction of the thermal behavior of the cable environment is necessary to be able to design cable routes both technically and economically sufficient. To investigate the coupled thermal and hydraulic processes around a cable like heat source with high temporal and spatial resolution at defined boundary conditions, a cylindrical laboratory test was designed and experiments with two soils conducted by Verschaffel-Drefke et al. (2021). The data collected can be used to validate models of coupled heat and mass transfer around power cables. Both the experimentally determined soil properties and the measured data of the three conducted test series are provided

Experiment for validation of numerical models of coupled heat and mass transfer around energy cables

The increasing decentralization of electrical energy production as well as an increasing number of fluctuating regenerative energy sources require significant investments in grid expansion. Among other assessments, an exact prediction of the thermal behavior of the cable environment is necessary to be able to design cable routes both technically and economically sufficient. To investigate the coupled thermal and hydraulic processes around a cable-like heat source with high temporal and spatial resolution under controlled boundary conditions, a cylindrical laboratory test was designed and experiments with two soils conducted. The data collected can be used to validate models of coupled heat and mass transfer around power cables. Within this study, the experimental data was compared with a modified model approach that is based on experimentally determined input data for the thermal and hydraulic properties of the examined soils. Although overall good agreement in the temperature field around the central heat source was observed, differences in the spatial distribution of the dry-out zone near the heat source led to some shift between the measured and simulated temperatures

Supplementary Information to ‘Heat Dissipation in variable Underground Power Cable Beddings: Experiences from a Real Scale Field Experiment'

The increasing decentralization of electrical energy production as well as an increasing number of fluctuating regenerative energy sources require significant investments in grid expansion. To prevent accelerated thermal aging or insulation faults in cable systems due to overheating, the current carrying capacity is usually limited by specific conductor temperatures. As the heat produced during the operation of underground cables has to be dissipated to the environment, the actual current carrying capacity of a power cable system is primarily dependent on the thermal properties of the surrounding porous bedding material and soil. To investigate the heat dissipation processes around buried power cables in real scale and with realistic electric loading, a field experiment consisting of a main field with various cable configurations, laid in four different bedding materials, and a side field with additional cable trenches for thermal enhanced bedding materials and protection pipe systems was planned and constructed by Verschaffel-Drefke et al. (2021). Both the experimentally determined bedding properties and the presented data of the conducted experiments are provided