Low Product Concentrations Research Articles

An Emerging Solid‐State Electrolyte Reactor to Drive the Future of Electrochemical Synthesis

AbstractElectrochemical reactors, powered by renewable electricity, have garnered widespread attention for chemical synthesis due to their low energy consumption and pollution‐free features. However, the inherent design flaw of traditional electrochemical reactors has persistently hindered the advancement of electrochemical synthesis, as they result in low product concentrations, low purity, and continuous production issues. As a novel electrochemical reactor, the porous solid‐state electrolyte (PSE) reactor is elaborately designed to overcome the limitation by enabling the direct and continuous synthesis of pure products, possessing a modular and scalable structure with high efficiency, safety, and long stability. In this work, first, the distinctive design of the PSE reactor, highlighting its structural features, core components, and variable configurations, is introduced. Furthermore, the configuration‐relevant applications in electrosynthesis, such as formic acid, acetic acid, and hydrogen peroxide (H2O2) production, are summarized. Integrated applications are also discussed, along with potential domains for improvements and optimization. Finally, the future developmental directions of the PSE devices are thoroughly explored. By addressing its unique design attributes, showcasing its capabilities, and envisioning prospective refinements and diverse applications, the aim is to boost the progression of this transformative technology toward widespread commercialization and industrial adoption, thereby revolutionizing sustainable electrochemical synthesis.

Pervaporation Separation of Isopropanol/Water Using Zeolite Nanosheets: A Molecular Simulation Study.

Reducing greenhouse gas emissions plays a crucial role in slowing down the rise of the global temperature. One of the viable options is to employ renewable energy sources such as alcohols that can be produced from biomass. Specifically, one of the most common alcohols is isopropanol (IPA). Energy-intensive distillation processes are however involved in its production because of the rather low product concentration from fermentation. Membrane technologies, specifically pervaporation (PV), represent a promising alternative to the IPA/water separation. Particularly, employing zeolite nanosheets as PV membranes may provide great opportunities to extract IPA owing to their ultrathin and hydrophobic nature. By employing molecular dynamics simulations, this study conducts a systematic study on a diverse set of nanosheet candidates with the aim of exploring their potential and identifying top-performing structures. The best candidate among structures studied herein is predicted to offer an exceptional IPA/water selectivity of more than 400 with an unprecedentedly large flux. Structure-property-performance relationships have also been established to offer insights into the rational design of PV membranes with improved performance.

КОРРЕЛЯЦИОННЫЙ АНАЛИЗ СИЛЫ СВЯЗИ МЕЖДУ РЕЗУЛЬТАТАМИ МОНИТОРИНГА АВАРИЙНОГО НЕФТЯНОГО ЗАГРЯЗНЕНИЯ ПОЧВ СКРИНИНГОВЫМИ МЕТОДАМИ

Major accidents at oil and gas industry enterprises related to soil contamination with petroleum products are considered. Based on the analysis of scientific research, it was determined that the existing methods for assessing the content of petroleum products in the soil have a number of significant limitations. Overcoming them requires the organization of a soil monitoring system, characterized by the possibility of rapid determination of pollutants and the allocation of clear boundaries of the permissible content of oil and petroleum products. The use of the arbitration method of infrared spectroscopy and the molecular luminescence method for estimating the content of petroleum products in the soil is experimentally justified. A correlation analysis was carried out between the measurement results obtained using the two presented methods. It was found that at low concentrations of petroleum products in soils, there is a linear dependence with a very high binding force, characterized by a Pearson correlation coefficient of 0,93. With relatively high values of the content of petroleum products in the soil and a significant spread of the experimental data obtained, it is advisable to use rank correlation. The use of the identified dependencies allows us to form a fairly complete picture of the situation in the study area associated with soil contamination with petroleum products, based on the results obtained using one of the presented screening methods. This greatly simplifies the procedure for assessing the state of the soil cover and creates prerequisites for reducing decision-making time and increasing the responsiveness to emerging emergencies.

Adaptable heat pump-assisted dividing-wall column design for intensified downstream processing of bio-propionic acid

Propionic acid is a valuable platform chemical that is usually produced via fossil routes. As these are energy-intensive and eco-unfriendly processes, fermentative production of propionic acid is becoming more attractive. However, the complex downstream processing (due to low achievable product concentrations, high water content, presence of by-products and thermodynamic constraints), presents a potential barrier to scale-up this technology. This original research proposes a novel intensified large-scale (production capacity of ∼ 20 ktonne/y) process for the final recovery of propionic acid after the initial biomass and counterion removal. Vacuum distillation steps ensure the recovery of a high-purity succinic acid product (>99.9 wt%) and a water stream that may be recycled to the fermentation to reduce the fresh water requirements. The main unit that follows is a highly integrated heat pump-assisted dividing-wall column (DWC), which allows the effective separation of propionic (>99.9 wt%) and acetic acid (99.4 wt%) products. Alternatively, it can serve as a reactive DWC that performs the esterification and separation of methyl propionate (99.8 wt%), methyl acetate (91.0 wt%) as higher added value products, and water by-product. If needed, extractive distillation can be implemented additionally to recover methyl acetate at higher purity (99.9 wt%). Overall, both options are proven to be economically interesting (recovery costs of 0.399 – 0.469 $/kg considering the product price of 1.349 – 1.802 $/kg) and environmentally attractive (3.206 – 3.678 kWthh/kg).

High cell density sequential batch fermentation for enhanced propionic acid production from glucose and glycerol/glucose mixture using Acidipropionibacterium acidipropionici

BackgroundPropionic acid fermentation from renewable feedstock suffers from low volumetric productivity and final product concentration, which limits the industrial feasibility of the microbial route. High cell density fermentation techniques overcome these limitations. Here, propionic acid (PA) production from glucose and a crude glycerol/glucose mixture was evaluated using Acidipropionibacterium acidipropionici, in high cell density (HCD) batch fermentations with cell recycle. The agro-industrial by-product, heat-treated potato juice, was used as N-source.ResultsUsing 40 g/L glucose for nine consecutive batches yielded an average of 18.76 ± 1.34 g/L of PA per batch (0.59 gPA/gGlu) at a maximum rate of 1.15 gPA/L.h, and a maximum biomass of 39.89 gCDW/L. Succinic acid (SA) and acetic acid (AA) were obtained as major by-products and the mass ratio of PA:SA:AA was 100:23:25. When a crude glycerol/glucose mixture (60 g/L:30 g/L) was used for 6 consecutive batches with cell recycle, an average of 35.36 ± 2.17 g/L of PA was obtained per batch (0.51 gPA/gC-source) at a maximum rate of 0.35 g/L.h, and reaching a maximum biomass concentration of 12.66 gCDW/L. The PA:SA:AA mass ratio was 100:29:3. Further addition of 0.75 mg/L biotin as a supplement to the culture medium enhanced the cell growth reaching 21.89 gCDW/L, and PA productivity to 0.48 g/L.h, but also doubled AA concentration.ConclusionThis is the highest reported productivity from glycerol/glucose co-fermentation where majority of the culture medium components comprised industrial by-products (crude glycerol and HTPJ). HCD batch fermentations with cell recycling are promising approaches towards industrialization of the bioprocess.

Concentrated formate produced through co‐electrolysis of CO2 and methanol in a zero‐gap electrolyzer

AbstractRecent progresses have highlighted the enormous potentials of renewable electricities driven carbon dioxide (CO2) electrolysis in achieving carbon neutrality. However, its further industrial application is limited by low liquid product concentrations, which requires energy‐intensive downstream separation processing. Herein we report a CO2 and methanol co‐electrolysis strategy to produce formate at both electrodes and collect highly concentrated formate in zero‐gap CO2 electrolyzers. An anion exchange membrane was employed to enable formate product crossover from cathode to anode. A bismuth silicate derived nanofiber electrocatalyst with rich grain boundaries was synthesized and exhibited excellent formate selectivity (Faradaic efficiency >95%), high activity (partial current density >500 mA cm−2), as well as good stability (>120 h). Coupled with NiOX anode catalyst for methanol selective oxidation to formate in a zero‐gap electrolyzer, we demonstrate a ~180% of formate Faradaic efficiency and a full‐cell voltage of 2.43 V at an industrially relevant current density of 0.2 A cm−2. By decoupling product generation and collection, our electrolyzer produced a highly concentrated formate of 3.24 M, which could be directly used as anode fuel for fuel cells.

Process systems engineering perspectives on eco-efficient downstream processing of volatile biochemicals from fermentation

Increasing concerns over environmental pollution, climate change and energy security are driving a necessary transition from fossil carbon sources to more sustainable alternatives. Due to lower environmental impact, biochemicals are rapidly gaining significance as a potential renewable solution, particularly of interest in Europe. In this context, process systems engineering (PSE) helps with the decision-making at multiple scales and levels, aiming for optimum use of (renewable) resources. Fermentation using waste biomass or industrial off-gases is a promising way for the production of these products. However, due to the inhibitory effects or low substrate concentrations, relatively low product concentrations can be obtained. Consequently, significant improvements in downstream processing are needed to increase the competitiveness of the overall bioprocesses. This paper supports sustainable development by providing new PSE perspectives on the purification of volatile bioproducts from dilute fermentation broths. Since purification significantly contributes to the total cost of biochemical production processes (20%–40% of the total cost), enhancing this part may substantially improve the competitiveness of the overall bioprocesses. The highly advanced downstream process offers the possibility of recovering high-purity products while enhancing the fermentation step by continuously removing inhibitory products, and recycling microorganisms with most of the present water. Besides higher productivity, the upstream process can be greatly improved by avoiding loss of biomass, enabling closed-loop operation and decreasing the need for fresh water. Applying heat pumping, heat integration and other methods of process intensification (PI) can drastically reduce energy requirements and CO2 emissions. Additionally, the opportunity to use renewable electricity instead of conventional fossil energy presents a significant step toward (green) electrification and decarbonization of the chemical industry.

Advanced purification of isopropanol and acetone from syngas fermentation

AbstractBACKGROUNDIsopropanol and acetone production by syngas fermentation is a promising alternative to conventional fossil carbon‐dependent production. However, this alternative technology has not yet been scaled up to an industrial level owing to the relatively low product concentrations (about 5 wt% in total). This original research aims to develop cost‐effective and energy‐efficient processes for the recovery of isopropanol and acetone from highly dilute fermentation broth (>94 wt% water) for large‐scale production (about 100 ktIPA+AC y−1).RESULTSVacuum distillation and pass‐through distillation enhanced with heat pumps or multi‐effect distillation were efficiently coupled with regular atmospheric distillation and extractive distillation in several innovative intensified downstream processes. Over 99.2% of isopropanol and 100% of acetone were recovered as high‐purity end‐products (>99.8 wt%). Advanced heat pumping (mechanical vapor recompression) and heat integration techniques were implemented to decrease total annual costs (0.109–0.137 USD kgIPA+AC−1), reduce energy requirements (1.348–2.043 kWth h kgIPA+AC−1) and lower CO2 emissions (0.067–0.191 kgCO2 kgIPA+AC−1), resulting in highly competitive recovery processes.CONCLUSIONThe proposed three novel isopropanol and acetone recovery processes from dilute broth significantly contribute to the expansion of sustainable industrial fermentation. Furthermore, this original research is the first one to develop novel pass‐through distillation technology for the complex isopropanol–acetone–water system. All the designed processes are highly economically competitive and environmentally viable. In addition to recovering efficiently both isopropanol and acetone, the designed downstream processes offer the possibility to enhance the fermentation process by recycling all the present microorganisms and reducing fresh‐water requirements. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Enhanced 5-hydroxymethylfurfural production from cellulose in monophasic molten salt hydrate: Insights into the effect of catalyst acidity on conversion

Production of 5-HMF from cellulose is a promising approach for advanced bio-fuels preparation, but the degradation of active 5-hydroxymethylfurfural (5-HMF) is a critical challenge affecting 5-HMF selectivity. To address this issue, biphasic reaction system consisting of water and organic solvent is generally used to in-situ extract 5-HMF into organic phase to inhibit product degradation. Despite the high 5-HMF selectivity achieved in biphasic system, low product concentration and difficulty in separation restrict its industrial applications. Molten salt hydrate (MSH) is unique in cellulose conversion and 5-HMF preservation. In this work, MSH of LiBr was used as monophasic solvent for cellulose conversion and an acidity tunable solid acid AlSiO-x was used as the catalyst. It was found that a relatively high 5-HMF yield of 44.5% together with carbon balance of 75.0% were obtained at 170 °C for 20 min, which is higher than the results ever reported. Importantly, this work proved that the ratio of total Brønsted to Lewis acid sites on solid acid is the key issue affected 5-HMF yield. After reaction, solid acid can be recycled for more than 5 times without catalytic performance decline, and the dissolved 5-HMF can be sufficiently separated from MSH via hyper cross-linked polymer (HCP) adsorption.

Continuous Fermentation Coupled with Online Gas Stripping for Effective Biobutanol Production

The main problems with the butanol fermentation process include high cost of grain raw materials, low product concentration and low butanol productivity caused by butanol cytotoxicity. In this study, cassava, a cheap crop, was used as the raw material. A symbiotic system TSH06, which possesses the capability to synthesize butanol under non-strict anaerobic conditions, was used as the fermentation strain. The fermentation performance of TSH06 in a cassava system was investigated. In order to eliminate product inhibition and promote the concentration and productivity of butanol, a strategy of continuous fermentation coupled with online gas stripping was developed. By using the strategy of two-stage continuous fermentation using immobilized cells coupled with online gas stripping, the butanol productivity reached 0.9 g/(L·h); at the same time, a high butanol concentration was achieved, and the concentration of butanol obtained in the condensate reached 71.2 g/L.

85 Incidence of Intravenous Immunoglobulins-related Adverse Events in Children

Abstract Background Intravenous immunoglobulins (IVIG) therapy is increasingly used in the treatment of various paediatric diseases. Data about frequency and underlying mechanisms of IVIG-related adverse events (IVIG-AEs) in children are limited. Objectives Objectives of this study were to document the incidence of IVIG-AEs in paediatric hospitalized patients and identify risk factors for IVIG-AEs. Design/Methods In this retrospective cohort study, we included patients aged < 18 years old who received IVIG therapy, for any indication, as inpatients at a Canadian paediatric tertiary care centre between 2016-2020. Patients and IVIG-perfusion characteristics were collected, as well as any AEs occurring during the perfusion or up to 10 days after. AEs were graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Bivariate and multivariate logistic regressions were used to explore the associations between patients’ characteristics and the incidence of IVIG-AEs. Results We included 228 children in this study (mean age: 4 years), receiving 478 IVIG infusions. Indications for IVIG infusions included inflammatory (120/228, 52.6%), replacement (27/228, 11.8%) and auto-immune (81/228, 35.5%) disorders. A total of 211 IVIG-AEs were reported in 89/228 (39%) of patients, and 125/478 (26.2%) of infusions. Fever (65/478, 13.6%) was the most frequent AE, followed by headache (32/478, 6.7%) and tachycardia (31/478, 6.5%). Most IVIG-AEs were of mild (121/211, 57%) or moderate (66/211, 31%) severity, but 12% (24/211) were severe reactions (serious AEs or grade 3-4), and no fatal reactions (grade 5) were encountered. The highest proportion of IVIG-AEs occurred when administered for inflammatory conditions. Older age, dehydration, first infusion, higher IVIG dosage and concurrent allergies were significantly associated with IVIG-AEs, while treatment with a steroid was significantly associated with a reduced risk of AEs. Conclusion IVIG-AEs are frequent in children. While most of them are self-limited, more serious complications may occur. Adequate hydration, low concentrations of IVIG products and the administration of glucocorticoid prior to the infusion could minimize these AEs. Further research is necessary to prevent IVIG-AEs in high-risk children.

Innovative char-sparger for improving volatile fatty acids (VFA) production in homoacetogenic fermentation of H2/CO2 with microbial mixed cultures (MMC)

The homoacetogenic fermentation of CO2 and H2 allows the production of renewable volatile fatty acids (VFA) using microbial mixed cultures (MMC). The main challenges of such approach, which would open a reliable power-to-X pathway, are the low product concentration and low volumetric productivity. To address such key features, which are due to product inhibition and low solubility of H2, biomass-derived biochar and polystyrene foam were used to manufacture a porous monolith (sparger) that allows the delivery of H2/CO2 to bacterially colonisable surfaces. Such device was used within a novel char-based biofilm sparger reactor (CBSR), which was tested for acetogenic fermentation of H2/CO2 with variable dilution rates. Noticeably, a low dilution rate (0.1 d−1) achieved the highest VFA concentration ever obtained (58 gCOD L−1 and 52 g/L acetic acid) with MMC, whereas a higher dilution rate (0.8 d−1) provided 15 gCOD L−1 VFA with a volumetric productivity of 18.5 gCOD L−1 d−1. According to the 16S rRNA sequencing of the biofilm microbiota, Acetobacterium was the dominant genus with a 90% relative abundance ratio. Such performances, which are close to that obtainable with optimised axenic fermentation, suggest that the innovative char–sparger could enhance mass transfer rate, shield from product inhibition and/or improve the growth of biofilm.

Efficient Purification of Polyhistidine-Tagged Recombinant Proteins Using Functionalized Corundum Particles.

Immobilized metal affinity chromatography (IMAC) is a popular and valuable method for the affinity purification of polyhistidine-tagged recombinant proteins. However, it often shows practical limitations, which might require cumbersome optimizations, additional polishing, and enrichment steps. Here, we present functionalized corundum particles for the efficient, economical, and fast purification of recombinant proteins in a column-free format. The corundum surface is first derivatized with the amino silane APTES, then EDTA dianhydride, and subsequently loaded with nickel ions. The Kaiser test, well known in solid-phase peptide synthesis, was used to monitor amino silanization and the reaction with EDTA dianhydride. In addition, ICP-MS was performed to quantify the metal-binding capacity. His-tagged protein A/G (PAG), mixed with bovine serum albumin (BSA), was used as a test system. The PAG binding capacity was around 3 mg protein per gram of corundum or 2.4 mg per 1 mL of corundum suspension. Cytoplasm obtained from different E. coli strains was examined as examples of a complex matrix. The imidazole concentration was varied in the loading and washing buffers. As expected, higher imidazole concentrations during loading are usually beneficial when higher purities are desired. Even when higher sample volumes, such as one liter, were used, recombinant protein down to a concentration of 1 µg/mL could be isolated selectively. Comparing the corundum material with standard Ni-NTA agarose beads indicated higher purities of proteins isolated using corundum. His6-MBP-mSA2, a fusion protein consisting of monomeric streptavidin and maltose-binding protein in the cytoplasm of E. coli, was purified successfully. To show that this method is also suitable for mammalian cell culture supernatants, purification of the SARS-CoV-2-S-RBD-His8 expressed in human Expi293F cells was performed. The material cost of the nickel-loaded corundum material (without regeneration) is estimated to be less than 30 cents for 1 g of functionalized support or 10 cents per milligram of isolated protein. Another advantage of the novel system is the corundum particles' extremely high physical and chemical stability. The new material should be applicable in small laboratories and large-scale industrial applications. In summary, we could show that this new material is an efficient, robust, and cost-effective purification platform for the purification of His-tagged proteins, even in challenging, complex matrices and large sample volumes of low product concentration.

Co-feeding enhances the yield of methyl ketones.

By combining computational and experimental work, we demonstrate that feeding ethanol in addition to glucose improves the yield of biotechnologically produced methyl ketones.

High-Cell-Density Yeast Oil Production with Diluted Substrates Imitating Microalgae Hydrolysate Using a Membrane Bioreactor

Microbial oil production from industrial waste streams and biogenic resources, such as biomass hydrolysates, is emerging as a sustainable alternative to use of fossil and vegetable oils. However, the carbon sources of these substrates are typically diluted, leading to low product concentrations and, therefore, high fermentation and downstream processing costs. In this study, high-cell-density yeast oil production with a defined medium, which imitated the sugar composition of a diluted substrate, a typical microalgal biomass hydrolysate, is carried out on a 50 L scale using a membrane bioreactor (MBR) consisting of a microfiltration unit suited for industrial application. The process was run on a semi-continuous mode to reduce operational costs. Oleaginous yeast Cutaneotrichosporon oleaginosus was used as a biocatalyst and lipid production was induced by phosphate deficiency in the medium with a C/P ratio of 3515 g g−1. In this way, high cellular lipid contents of up to 76.5% (w/w) of dry cell mass, an average lipid yield of 32% (w/w), and a lipid space–time yield (STY) of up to 8.88 g L−1 d−1 were achieved with final high cell densities of up to 116 g L−1 dry biomass. Furthermore, use of a defined medium and elemental analysis of the yeast cells and yeast oil enabled drawing an accurate carbon mass balance of the production system. Carbon conversion efficiencies—fraction of total carbon supplied in the form of sugars converted into lipids at the end of the process—of up to 61.5% were achieved from diluted substrates using the MBR with total cell retention. Considering these results, it is concluded that utilization of an MBR on a semi-continuous mode would be very reasonable for yeast oil production, enabling high productivities with diluted sugar substrates.

Prediction of surfactin fermentation with Bacillus subtilis DSM10 by response surface methodology optimized artificial neural network.

Biosurfactants produced by Bacillus species are an emerging group of surface-active molecules. They have excellent surface tension reducer and high emulsifier properties. Generally, the biosurfactant fermentation leads to a low product concentration. Therefore, our goal was to investigate Bacillus subtilis DSM10 production and improve the biosurfactant content in the broth by media optimization via response surface methodology. The optimal combinations of the investigated factors were determined as the following: pH = 9, glucose = 20 g/L, and NH4 NO3 = 2 g/L. Under the optimized conditions, the formed surfactin strain reduced surface tension in the broth by 48% (from 72to 37 mN/m) and the isolated product by 63%(from 72to 27 mN/m). An artificial neural network was built based on the results of response surface methodology to predict the product quality and the harvesting time of broth. Thus, finally, the model can predict the final cell and product amount, and even their time course, with around 90% reliability.

Metal-organic frameworks-based hydrogen storage strategies and applications

Against the backdrop of rising emissions of greenhouse gasses and the need for sustainable fuel, hydrogen storage has recently become a popular energy storage option due to its many benefits, such as high energy capacity, low concentrations of side products, and relative ease of access. However, hydrogen storage is not perfect and possesses some critical flaws that prevent it from reaching its full potential, which include volatility and flammability. There are many candidates for hydrogen storage and also extant technologies to target hydrogen storage. Among all the ways proposed to store hydrogen, metal-organic frameworks (MOFs) have become increasingly popular because of their exemplary high surface area and adaptable pore structure. This research explores the various developments of MOFs in the field of hydrogen storage and how they may be improved and compared to one another. It will discuss the issues with current MOFs and design procedures and elements, such as making use of void spaces in MOFs. Then it will proceed to explore how MOFs have been enhanced through impregnation, catenation, and open metal sites. Lastly, this review will feature some breakthrough MOFs that have been promising for hydrogen storage.

Effect of roasting treatment on the micromorphology, gelatinization, structure, and digestibility of whole oat flour

Roasting is the primary link in Chinese traditional whole oat food processing, but the role of roasting is rarely explored. This study aimed to clarify the effects of roasting treatment (160 °C, 0–60 min) of oat kernels on the characteristics of oat flour from the aspects of micromorphology, constituents, gelation, structure, and starch digestibility. Results showed roasting treatment disrupted the structure of oat kernels, promoted the release of lipids, and caused the aggregation and wrapping of oat flour particles. After roasting treatment, starch and protein content of whole oat flour did not change significantly, but lipid content increased and β-glucan content decreased. The roasted samples had better water absorption (25 °C, 2.41–2.69 g/g), swelling power (25 °C, 2.44–2.78), and solubility (100 °C, 25.40–28.11%), lower pasting viscosity (final viscosity, 1.84–3.61 Pa s), higher gel strength, and lower short-range order. Pasting viscosities and gel properties with roasting time conformed to the second-order polynomial model. Oat flour from roasting oat kernels for 40 min had the highest crystallinity (19.74%), the highest digestibility rate constant (k, 0.07), and lower product concentration (Cꝏ, 77.74%). These results will contribute to the application of roasting technology in the modification of whole oats.

Separation of α‐ketoglutaric acid by salting‐out extraction coupled with solar‐driven distillation

AbstractAlpha‐ketoglutaric acid (α‐KG), as an essential intermediate in biosynthesis and drug synthesis, has a broad application prospect. However, the lower product concentration and impurities in the α‐KG production make the downstream separation more complex and costly. In this study, α‐KG was separated from biotransformation broth by salting‐out extraction (SOE) combined with solar‐driven distillation. First, the aqueous two‐phase system (ATPS) consisting of acetone/(NH4)2SO4 was selected by comparison. The effects of acetone/(NH4)2SO4 concentration, temperature, α‐KG concentration, and pH on the distribution behavior of α‐KG in ATPS were investigated. Under the optimized conditions, higher extraction efficiency and purity of α‐KG were obtained in the actual biotransformation broth. In addition, solar evaporation was used to achieve preconcentration of the organic phase and salt recovery, significantly reducing energy consumption. The method is environmentally friendly and easy to operate, providing a new idea for separating low concentration products in biosynthesis.

MO714: PARK7—A Novel Therapeutic Target for Peritoneal Dialysis Induced Peritoneal Membrane and Vascular Transformation

Abstract BACKGROUND AND AIMS Patients with chronic kidney disease (CKD) suffer from increased oxidative stress, which is further aggravated in patients on peritoneal dialysis (PD). Parkinson disease protein 7 (PARK7) has antioxidant and antiapoptotic activity; its role in PD is unknown. METHOD Transcriptome and proteome data sets from microdissected omental arterioles obtained from age-matched non-CKD children, children with CKD5 and children on PD with fluids containing low or high concentrations of glucose degradation products (GDP; n = 6/group) underwent PARK7 related gene set analysis (FDR < 0.05). Respective parietal peritoneal tissues (n = 60) underwent digital histomorphometry analyses. PARK7 western blotting was performed in effluents of eight children on high-GDP PD. Human umbilical endothelial cells (HUVEC) viability (MTT assay) and transepithelial electrical resistance (TER, Transwells) and 4-, 10- and 70-kDa dextran transport were measured (n = 6–12/group). As an extreme phenotype approach of PD toxicity, C57/BL6J mice were treated with chlorhexidine digluconate (CG) and PARK7 activator for 7 days and parietal peritoneal damage was quantitated (n = 6–8/group). RESULTS Arteriolar transcriptome analyses in children on low-GDP PD demonstrated the enrichment of PARK7 related GO terms of oxidant detoxification as compared to CKD5 and in children on high-GDP PD that of reactive oxygen species-, mitochondria- and apoptosis-related processes. On the proteome level the DNA repair/organization, catabolic and mitochondria associated processes were enriched in children on low-GDP PD, and mitochondrial processes in children on high-GDP PD. PARK7 was detected in the parietal peritoneal tissues in mesothelial, endothelial and inflammatory cells, in myocytes and fibroblasts and was present in the PD effluents. Total peritoneal and submesothelial PARK7 abundance was similar in controls, patients with CKD5 and in patients on low-GDP PD, but 2-fold increased in patients on high GDP PD compared to controls and CKD5. Mesothelial PARK7 was 2-fold increased in children on low-GDP PD versus CKD5, endothelial PARK7 abundance was similar in all four groups. In low-GDP PD patients endothelial PARK7 abundance correlated with vessel lumen/vessel diameter ratio (r = 0.53, P = 0.06), i.e. inversely with lumen obliteration. Submesothelial PARK7 correlated with microvessel density (r = 0.55, P = 0.05), with submesothelial hypoxia inducible factor-1 and angiopoietin-1 and -2 (ρ = 0.63, P = 0.023; r = 0.91, P < 0.0001; r = 0.60, P = 0.03) but not with VEGF. Submesothelial and endothelial PARK7 correlated with respective caspase 3 abundances (r = 0.74/0.68, P = 0.009/0.015). In HUVEC methylglyoxal (MG) dose- and time-dependently reduced viability, coincubation with PARK7 activator partially preserved endothelial cell viability. In Transwells, MG treatment decreased TER and increased dextran transport, but none of them was improved by PARK7 activation. In mice treated with CG submesothelial thickness was 2-fold increased, microvessel density was unchanged; PARK7 protein abundance was 5-fold reduced. Co-treatment of CG with PARK7 activator prevented the submesothelial thickening. CONCLUSION PD modifies arteriolar PARK7 related biological processes of oxidant detoxification, mitochondria- and apoptosis-related processes. PARK7 is ubiquitously expressed in the parietal peritoneum and regulated by the GDP content of PD fluids. In patients on low-GDP PD, PARK7 abundance correlated with the degree of arteriolar lumen narrowing, and VEGF-independent angiogenesis. Activation of PARK7 preserves endothelial cell viability in vitro and prevents CG induced peritoneal membrane damage in mice and thus represents a potential novel therapeutic approach.