Investigation of spiral-wound membrane modules for the cross-flow nanofiltration of fermentation broth obtained from a pilot plant fermentation reactor for the continuous production of lactic acid

Background: The separation performance of seven polymer membranes for the nanofiltration of sodium lactate in fermentation broth was investigated. Each module was introduced into the test stand, and the system curve was obtained by recording the permeate flow velocity at different pump head levels. Performance benchmarks were good permeate quality, as determined by high permeate flow velocity, high sodium lactic concentration, low ion impurity concentration, and low organic impurity concentration. Market research has shown that three companies, DOW (TW30, SW30, NF45), General Electric (DK73, DL73), and Microdyn-Nadir (NP30), distributed spiral-wound membrane modules for cross-flow filtration in a 2.5 by 40-in. module size, suitable for operation in the filtration test stand. Results: The measured permeate flow velocity was found to vary widely between the membranes. At a pump head of 250 m, DK73, NP30, and DL73 generated more than 200, 300, and 400% higher permeate flow velocities, respectively, than TW30 and NF45. A key benchmark, lactate rejection, was also highly dependent upon membrane type. The NP30, NF45, and TW30 membranes showed a decrease in lactate permeate flow velocity of 117, 83, and 348% starting at 205, 250, and 300 m, respectively. Conclusions: The DL73 had the overall best performance according to the measured fermentation broth and lactic acid permeability. The presented method for the graphical analysis of the membrane performance proofed to be a useful tool for the filtration engineer. © 2017, The Author(s)

Future heat extremes and impacts in a convection permitting climate ensemble over Germany

Heat extremes and associated impacts are considered the most pressing issue for German regional governments with respect to climate adaptation. We explore the potential of an unique high-resolution convection permitting (2.8 km), multi-GCM ensemble with COSMO-CLM regional simulations (1971&ndash;2100) over Germany regarding heat extremes and related impacts. We find an improved mean temperature beyond the effect of a better representation of orography on the convection permitting scale, with reduced bias particularly during summer. The projected increase in temperature and its variance favors the development of longer and hotter heat waves, especially in late summer and early autumn. In a 2&deg; (3&deg;) warmer world, a 26 % (100 %) increase in the Heat Wave Magnitude Index is anticipated. Human heat stress (UTCI &gt; 32&deg;C) and local-specific parameters tailored to climate adaptation, revealed a dependency on the major landscapes, resulting in significant higher heat exposure in flat regions as the Rhine Valley, accompanied by the strongest absolute increase. A non-linear, exponential increase is anticipated for parameters characterizing strong heat stress (UTCI &gt; 32&deg;C, tropical nights, very hot days). Providing local-specific and tailored climate information, we demonstrate the potential of convection permitting simulations to facilitate improved impact studies and narrow the gap between climate modelling and stakeholder requirements for climate adaptation.</p

CE-UV/VIS and CE-MS for monitoring organic impurities during the downstream processing of fermentative-produced lactic acid from second-generation renewable feedstocks

During the downstream process of bio-based bulk chemicals, organic impurities, mostly residues from the fermentation process, must be separated to obtain a pure and ready-to-market chemical. In this study, capillary electrophoresis was investigated for the non-targeting downstream process monitoring of organic impurities and simultaneous quantitative detection of lactic acid during the purification process of fermentatively produced lactic acid. The downstream process incorporated 11 separation units, ranging from filtration, adsorption and ion exchange to electrodialysis and distillation, and 15 different second-generation renewable feedstocks were processed into lactic acid. The identification of organic impurities was established through spiking and the utilization of an advanced capillary electrophoresis mass spectrometry syste

Skill and added value of the MiKlip regional decadal prediction system for temperature over Europe

In recent years, several decadal prediction systems have been developed to provide multi-year predictions of the climate for the next 5–10 years. On the global scale, high decadal predictability has been identified for the North Atlantic sector, often extending over Europe. The first full regional hindcast ensemble, derived from dynamical downscaling, was produced within the German MiKlip project (‘decadal predictions’). The ensemble features annual starting dates from 1960 to 2017, with 10 decadal hindcasts per starting year. The global component of the prediction system uses the MPI-ESM-LR and the downscaling is performed with the regional climate model COSMO-CLM (CCLM). The present study focusses on a range of aspects dealing with the skill and added value of regional decadal temperature predictions over Europe. The results substantiate the added value of the regional hindcasts compared to the forcing global model as well as to un-initialized simulations. The results show that the hindcasts are skilful both for annual and seasonal means, and that the scores are comparable for different observational reference data sets. The predictive skill increases from earlier to more recent start-years. A recalibration of the simulation data generally improves the skill further, which can also be transferred to more user-relevant variables and extreme values like daily maximum temperatures and heating degree-days. These results provide evidence of the potential for the regional climate predictions to provide valuable climate information on the Abstract Formulae display:MathJax Logo? In recent years, several decadal prediction systems have been developed to provide multi-year predictions of the climate for the next 5–10 years. On the global scale, high decadal predictability has been identified for the North Atlantic sector, often extending over Europe. The first full regional hindcast ensemble, derived from dynamical downscaling, was produced within the German MiKlip project (‘decadal predictions’). The ensemble features annual starting dates from 1960 to 2017, with 10 decadal hindcasts per starting year. The global component of the prediction system uses the MPI-ESM-LR and the downscaling is performed with the regional climate model COSMO-CLM (CCLM). The present study focusses on a range of aspects dealing with the skill and added value of regional decadal temperature predictions over Europe. The results substantiate the added value of the regional hindcasts compared to the forcing global model as well as to un-initialized simulations. The results show that the hindcasts are skilful both for annual and seasonal means, and that the scores are comparable for different observational reference data sets. The predictive skill increases from earlier to more recent start-years. A recalibration of the simulation data generally improves the skill further, which can also be transferred to more user-relevant variables and extreme values like daily maximum temperatures and heating degree-days. These results provide evidence of the potential for the regional climate predictions to provide valuable climate information on the decadal time-scale to users

Aufreinigung von Milchsäure aus nachwachsenden Rohstoffen

Der Schwerpunkt dieser Arbeit liegt auf der Aufreinigung von Milchsäure aus Fermentationslösungen als Ausgangsstoff für die Polymerchemie. Dabei kommt der chemischen Prozessanalyse als Ausgangspunkt für die Evaluierung der jeweiligen Effektivität des Prozessschrittes eine wichtige Rolle zu. Es wurde eine Kapillarelektrophorese-Methode mittels UV/VIS-Detektor entwickelt, welche neben Milchsäure weitere organische Säuren und Aminosäuren erfasst. Dabei konnte der intrazellulare Metabolit, Pyroglutamin, identifiziert und anhand von Laborversuchen sein negativer Einfluss auf den Polymerisationsprozess der Milchsäure nachgewiesen werden. Des Weiteren wurden an Chitosan, Alginat, Weide und Papel, und ihren pyrolisierten Aktivkohleprodukten Ionenaustauchversuche durchgeführt und diese mit den Werten kommerzieller Adsorber verglichen. Die Versuche habe ge-zeigt, dass sowohl die Ionenart als auch die adsorbierte Menge von dem verwende-ten Rohstoff als auch im Bereich des Holzes von der Pyrolyse abhängig ist. Die Fähigkeit zur Regenerierung dieser natürlichen Adsorbern, für den erneuten Einsatz, wurde ebenfalls belegt. Diese biologisch abbaubaren Adsorbern können nach ihrer Erschöpfung weiter als Bodenverbesserer in der Landwirtschaft ver-wendet werden. Demnach entfällt eine kostenpflichtige Entsorgung, was deren Wirtschaftlichkeit erhöht. Im Bereich der Nanofiltration wurde eine Methode zur Bestimmung des Membranwiederstandes innerhalb einer Filtrationsanlage entwickelt. Dabei wur-den sieben Nanofiltrationsmodule auf ihre Verwendbarkeit für die Filtration von Milchsäure-Fermentationslösungen hin untersucht. Die Methode erlaubt es dabei den wirtschaftlich optimalen Betriebsdruck des Membranmoduls zu ermitteln. Der Druck auf der Feed-Seite hatte zwar Einfluss auf den Volumenstrom auf der Permeat-Seite, jedoch wurde die Milchsäure-Rückhaltung stark durch das Memb-ranmaterial beeinflusst. Eine Untersuchung der Metaboliten im Permeat hat ge-zeigt, dass alle Membranen die gleichen Fraktionen an Verunreinigungen durch-lassen. Diese Untersuchungen sind insofern wichtig, da anhand der Herstelleran-gaben sich keine eindeutige Kaufempfehlung von Modulen für die Nanofiltration von Milchsäure geben lässt.The primary focus of this thesis is the chemical analysis of a downstream process (DSP) to produce lactic acid as a feedstock for the polymer industry. The feedstock for the lactic acid fermentation process consists of renewable resources. Lactate is produced in its sodium lactate form by bacteria and must be cleaned and converted into its acid form by the DSP. Chemical analysis is of great importance because it permits an evaluation of the efficiency of both the single unit operation and the entire DSP. In this thesis, a capillary electrophoresis method based on UV/VIS detection was developed. This method can detect lactic acid, various or-ganic acids and amino acids in a single run. Peak identification was conducted ei-ther by spiking the samples with reference substances or by using a mass spec-trometry detector to find the metabolite, pyroglutamic acid. Laboratory experi-ments proved that pyroglutamic acid negatively affects the polymerization of lac-tic acid into poly-lactic acid. The use of renewables for lactic acid production was expanded from the fer-mentation process to the DSP. The renewables alginate, chitosan, papule, willow and their activated char forms were used for ion adsorption. The results were com-pared to those obtained for commercial adsorber resins. The experiments showed that the type of ion and the number of adsorbed ions depended on the type of re-source and, in the case of wood, could be altered through pyrolysis. The capacity for biologic adsorbent regeneration was also demonstrated. The biologic adsor-bents can be further used as fertilizers after they are exhausted. In contrast to petrochemical adsorber resins, no waste disposal costs are charged, which enhanc-es the economic potential of bio-adsorber resins. Furthermore, a method for estimating the nanofiltration membrane re-sistance of the filtration modules was introduced. Seven different nanofiltration modules were investigated for their lactic acid fermentation broth filtration per-formance. The method permits the estimation of the economically optimal feed pressure operating conditions. The feed pressure strongly influenced the permeate stream velocity. However, lactic acid rejection was dependent on the membrane material. The generated membrane performance data are very important because none are provided by the manufacturer

Investigation of spiral-wound membrane modules for the cross-flow nanofiltration of fermentation broth obtained from a pilot plant fermentation reactor for the continuous production of lactic acid

Abstract Background The separation performance of seven polymer membranes for the nanofiltration of sodium lactate in fermentation broth was investigated. Each module was introduced into the test stand, and the system curve was obtained by recording the permeate flow velocity at different pump head levels. Performance benchmarks were good permeate quality, as determined by high permeate flow velocity, high sodium lactic concentration, low ion impurity concentration, and low organic impurity concentration. Market research has shown that three companies, DOW (TW30, SW30, NF45), General Electric (DK73, DL73), and Microdyn-Nadir (NP30), distributed spiral-wound membrane modules for cross-flow filtration in a 2.5 by 40-in. module size, suitable for operation in the filtration test stand. Results The measured permeate flow velocity was found to vary widely between the membranes. At a pump head of 250\ua0m, DK73, NP30, and DL73 generated more than 200, 300, and 400% higher permeate flow velocities, respectively, than TW30 and NF45. A key benchmark, lactate rejection, was also highly dependent upon membrane type. The NP30, NF45, and TW30\ua0membranes showed a decrease in lactate permeate flow velocity of 117, 83, and 348% starting at 205, 250, and 300 m, respectively. Conclusions The DL73 had the overall best performance according to the measured fermentation broth and lactic acid permeability. The presented method for the graphical analysis of the membrane performance proofed to be a useful tool for the filtration engineer

CE-UV/VIS and CE-MS for monitoring organic impurities during the downstream processing of fermentative-produced lactic acid from second-generation renewable feedstocks

Background: During the downstream process of bio-based bulk chemicals, organic impurities, mostly residues from the fermentation process, must be separated to obtain a pure and ready-to-market chemical. In this study, capillary electrophoresis was investigated for the non-targeting downstream process monitoring of organic impurities and simultaneous quantitative detection of lactic acid during the purification process of fermentatively produced lactic acid. The downstream process incorporated 11 separation units, ranging from filtration, adsorption and ion exchange to electrodialysis and distillation, and 15 different second-generation renewable feedstocks were processed into lactic acid. The identification of organic impurities was established through spiking and the utilization of an advanced capillary electrophoresis mass spectrometry system. Results: A total of 53 % of the organic impurities were efficiently removed via bipolar electrodialysis; however, one impurity, pyroglutamic acid, was recalcitrant to separation. It was demonstrated that the presence of pyroglutamic acid disrupts the polymerization of lactic acid into poly lactic acid. Pyroglutamic acid was present in all lactic acid solutions, independent of the type of renewable resource or the bacterium applied. Pyroglutamic acid, also known as 5-oxoproline, is a metabolite in the glutathione cycle, which is present in all living microorganisms. pyroglutamic acid is found in many proteins, and during intracellular protein metabolism, N-terminal glutamic acid and glutamine residues can spontaneously cyclize to become pyroglutamic acid. Hence, the concentration of pyroglutamic acid in the lactic acid solution can only be limited to a certain amount. Conclusions: The present study proved the capillary electrophoresis system to be an important tool for downstream process monitoring. The high product concentration encountered in biological production processes did not hinder the capillary electrophoresis from separating and detecting organic impurities, even at minor concentrations. The coupling of the capillary electrophoresis with a mass spectrometry system allowed for the straightforward identification of the remaining critical impurity, pyroglutamic acid. Although 11 separation units were applied during the downstream process, the pyroglutamic acid concentration remained at 12,900 ppm, which was comparatively high. All organic impurities found were tracked by the capillary electrophoresis, allowing for further separation optimization

The regional MiKlip decadal prediction system for Europe: Hindcast skill for extremes and user‐oriented variables

Regional climate predictions for the next decade are gaining importance, as this period falls within the planning horizon of politics, economy, and society. The potential predictability of climate indices or extremes at the regional scale is of particular interest. The German MiKlip project (“mid‐term climate forecast”) developed the first regional decadal prediction system for Europe at 0.44° resolution, based on the regional model COSMO‐CLM using global MPI‐ESM simulations as boundary conditions. We analyse the skill of this regional system focussing on extremes and user‐oriented variables. The considered quantities are related to temperature extremes, heavy precipitation, wind impacts, and the agronomy sector. Variables related to temperature (e.g., frost days, heat wave days) show high predictive skill (anomaly correlation up to 0.9) with very little dependence on lead‐time, and the skill patterns are spatially robust. The skill patterns for precipitation‐related variables (e.g., heavy precipitation days) and wind‐based indices (like storm days) are less skilful and more heterogeneous, particularly for the latter. Quantities related to the agronomy sector (e.g., growing degree days) show high predictive skill, comparable to temperature. Overall, we provide evidence that decadal predictive skill can be generally found at the regional scale also for extremes and user‐oriented variables, demonstrating how the utility of decadal predictions can be substantially enhanced. This is a very promising first step towards impact‐related modelling at the regional scale and the development of individual user‐oriented products for stakeholders.The skill of the regional MiKlip decadal prediction system is analysed focussing on extremes and user‐oriented variables. Variables related to temperature extremes and the agronomy sector show high predictive skill with very little dependence on lead‐time. Skill patterns for precipitation‐related variables and wind‐based indices are less skilful and more heterogeneous, especially for the latter.The study was mainly funded by the Bundesministerium für Bildung und Forschung (BMBF) under project FONA MiKlip‐II http://dx.doi.org/10.13039/501100002347AXA Research Fund http://dx.doi.org/10.13039/50110000196

Additional file 1: of CE-UV/VIS and CE-MS for monitoring organic impurities during the downstream processing of fermentative-produced lactic acid from second-generation renewable feedstocks

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