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Due to their chemical and physical properties, rare earth elements (REEs) are essential in modern applications such as energy conversion or IT technology. The increasing demand for these elements leads to strong incentives for REE recovery and induces the exploration of new, alternative sources for REEs. Accessing REEs from clay minerals, in our case kaolinite, by an elution process is a promising method. The present study investigates the potential application of REE recovery through elution with different mineral acids (HNO3, H2SO4, and HCl) in a microwave process. The material used in this study—residues from an industrial kaolin production process—contained 2.47 g/kg REEs which is a significant amount for REE recovery. The ability of various mineral acids to solubilize metals was studied to assess the REE content of this residual resource. Around 1.87 g/kg of REEs was eluted from industrial kaolinite residues in hydrochloric acid, 1.71 g/kg in sulfuric acid, and 1.13 g/kg in nitric acid. [ABSTRACT FROM AUTHOR]

Elevated carbon dioxide (eCO2) and rising temperatures will have far‐reaching effects on global plant‐insect interactions, yet their implications for future biological control programs are not fully understood. Studies have shown that elevated CO2 will affect insect feeding guilds differently and these responses can be predicted with some confidence. Water hyacinth, Pontederia crassipes Mart. (Pontederiaceae), is a native and representative species of the Del Plata wetlands (Argentina) that invades outside of its native environment. It is considered one of the world's worst aquatic weeds and a target for biological control. In this study, water hyacinth plants were grown under two CO2 concentrations – current (400 p.p.m.) or elevated (800 p.p.m.) –, with and without two biocontrol agents representing different feeding guilds, the leaf‐chewing Cornops aquaticum Brüner (Orthoptera: Acrididae) and the phloem‐feeding Megamelus scutellaris Berg (Hemiptera: Delphacidae). Under eCO2 concentration, photosynthetic rate, total dry weight, and relative growth rate of P. crassipes acclimated to eCO2 conditions and plants showed very little CO2 fertilization response in eutrophic water. Insect herbivory varied depending on feeding guilds at eCO2; however, P. crassipes growth responses increased when exposed to insect herbivory. Chewing herbivory by C. aquaticum was consistent across CO2 conditions, whereas the feeding by M. scutellaris increased substantially at eCO2. These results indicate that successful biological control of P. crassipes under conditions of elevated CO2 might rely on phloem‐feeding insects, with chewers playing a lesser role. [ABSTRACT FROM AUTHOR]

Systems engineering activities in the concept and development phases have evolved continuously for decades. The deployment of digital thread, digital engineering, MBSE approaches, and modeling and simulation techniques have driven part of this evolution. Despite this trend, requirements are still largely textual and expressed in natural language, and requirements engineering activities are still often document‐based. However, model‐based requirements‐engineering approaches have emerged in recent years and have demonstrated significant benefits, including improved requirements quality, less ambiguity, and early and efficient verification and validation. The goal of this paper is to present the current outcomes and perspectives of setting up an Integrated Digital Requirements Engineering approach as developed within our company. This approach seeks to optimize usability and maximize benefits to support end‐to‐end V&V activities while fully integrating into MBSE workflows. [ABSTRACT FROM AUTHOR]

Iron reduction and sulfate reduction often occur simultaneously in anoxic systems, and where that is the case, the molar ratio between the reactions (i.e., Fe/SO42− reduced) influences their impact on water quality and carbon storage. Previous research has shown that pH and the supply of electron donors and acceptors affect that ratio, but it is unclear how their influences compare and affect one another. This study examines impacts of pH and the supply of acetate, sulfate, and goethite on the ratio of iron to sulfate reduction in semi‐continuous sediment bioreactors. We examined which parameter had the greatest impact on that ratio and whether the parameter influences depended on the state of each other. Results show that pH had a greater influence than acetate supply on the ratio of iron to sulfate reduction, and that the impact of acetate supply on the ratio depended on pH. In acidic reactors (pH 6.0 media), the ratio of iron to sulfate reduction decreased from 3:1 to 2:1 as acetate supply increased (0–1 mM). In alkaline reactors (pH 7.5 media), iron and sulfate were reduced in equal proportions, regardless of acetate supply. Secondly, a comparison of experiments with and without sulfate shows that the extent of iron reduction was greater if sulfate reduction was occurring and that the effect was larger in alkaline reactors than acidic reactors. Thus, the influence of sulfate supply on iron reduction extent also depended on pH and suggests that iron reduction grows more dependent on sulfate reduction as pH increases. Our results compare well to trends in groundwater geochemistry and provide further evidence that pH is a major control on iron and sulfate reduction in systems with crystalline (oxyhydr)oxides. pH not only affects the ratio between the reactions but also the influences of other parameters on that ratio. [ABSTRACT FROM AUTHOR]

Methanogenesis and iron reduction play major roles in determining global fluxes of greenhouse gases. Despite their importance, environmental factors that influence their interactions are poorly known. Here, we present evidence that pH significantly influences the balance between each reaction in anoxic environments that contain ferric (oxyhydr)oxide minerals. In sediment bioreactors that contained goethite as a source of ferric iron, both iron reduction and methanogenesis occurred but the balance between them varied significantly with pH. Compared to bioreactors receiving acidic media (pH 6), electron donor oxidation was 85% lower for iron reduction and 61% higher for methanogenesis in bioreactors receiving alkaline media (pH 7.5). Thus, methanogenesis displaced iron reduction considerably at alkaline pH. Geochemistry data collected from U.S. aquifers demonstrate that a similar pattern also exists on a broad spatial scale in natural settings. In contrast, in bioreactors that were not augmented with goethite, clay minerals served as the source of ferric iron and the balance between each reaction did not vary significantly with pH. We therefore conclude that pH can regulate the relative contributions of microbial iron reduction and methanogenesis to carbon fluxes from terrestrial environments. We further propose that the availability of ferric (oxyhydr)oxide minerals influences the extent to which the balance between each reaction is sensitive to pH. The results of this study advance our understanding of environmental controls on microbial methane generation and provide a basis for using pH and the occurrence of ferric minerals to refine predictions of greenhouse gas fluxes. [ABSTRACT FROM AUTHOR]

Abstract: Relevant for engineering a wide range of technological systems, Property Model Methodology (PMM) is applied in this paper to the development process of a helicopter function in the frame of the ARP4754A/ED79A. After a short presentation of the method, the case study is presented: “to retract and to extend airborne the landing gear system”. Then, each stage of the PMM development process is illustrated by examples from the case study: (1) Modeling the top level requirements specification, (2) Validating the requirements specification by proof and simulation, (3) Modeling the architectural design, Refining the top level requirements into requirements specified to the different subsystems contributing to the function and Modeling the terminal subsystems detailed designs (4) Validating the requirements specified to the contributing subsystems by proof or simulation, (5) Verifying the design models by simulation and finally (6–8) Verifying physical implementations by test on the basis of all validation and verification scenarios accumulated throughout the development. At end, lessons learnt and industrial perspectives are summarized highlighting how PMM is a methodology adapted to the challenges facing to systems engineering by the globalization of development processes and showing how PMM can provide a powerful conceptual framework to support digital continuity within globalized Design Organizations. Modeling, simulation, proof and test generation activities are supported by the MATLAB and Simulink products. [ABSTRACT FROM AUTHOR]

Glucosylceramides (GlcCer), glucose-conjugated sphingolipids, are major components of the endomembrane system and plasma membrane in most eukaryotic cells. Yet the quantitative significance and cellular functions of GlcCer are not well characterized in plants and other multi-organ eukaryotes. To address this, we examined Arabidopsis lines that were lacking or deficient in GlcCer by insertional disruption or by RNA interference ( RNAi) suppression of the single gene for GlcCer synthase ( GCS, At2g19880), the enzyme that catalyzes GlcCer synthesis. Null mutants for GCS (designated ' gcs-1') were viable as seedlings, albeit strongly reduced in size, and failed to develop beyond the seedling stage. Heterozygous plants harboring the insertion allele exhibited reduced transmission through the male gametophyte. Undifferentiated calli generated from gcs-1 seedlings and lacking GlcCer proliferated in a manner similar to calli from wild-type plants. However, gcs-1 calli, in contrast to wild-type calli, were unable to develop organs on differentiation media. Consistent with a role for GlcCer in organ-specific cell differentiation, calli from gcs-1 mutants formed roots and leaves on media supplemented with the glucosylated sphingosine glucopsychosine, which was readily converted to GlcCer independent of GCS. Underlying these phenotypes, gcs-1 cells had altered Golgi morphology and fewer cisternae per Golgi apparatus relative to wild-type cells, indicative of protein trafficking defects. Despite seedling lethality in the null mutant, GCS RNAi suppression lines with ≤2% of wild-type GlcCer levels were viable and fertile. Collectively, these results indicate that GlcCer are essential for cell-type differentiation and organogenesis, and plant cells produce amounts of GlcCer in excess of that required for normal development. [ABSTRACT FROM AUTHOR]

N-methylated tryptamines, such as the hallucinogenic natural products, psilocybin and N,N-dimethyltryptamine (DMT), are gaining interest from the medical community due to their potential as next generation treatments for mental health disorders. The clinical relevance of these compounds has driven scientists to develop biosynthetic production routes to a number of tryptamine drug candidates, and efforts are ongoing to expand and further develop these biosynthetic capabilities. To that end, we have further characterized the substrate preferences of two enzymes involved in tryptamine biosynthesis: TrpM, a tryptophan N-methyltransferase from Psilocybe serbica, and PsiD, the gateway decarboxylase of the psilocybin biosynthesis pathway. Here, we show that TrpM can N-methylate the non-native amino acid substrate, 4-hydroxytryptophan, a key intermediate in the Escherichia coli-based recombinant psilocybin biosynthesis pathway. However, the ability to incorporate TrpM into a functional psilocybin biosynthesis pathway was thwarted by PsiD's inability to use N,N-dimethyl-4-hydroxytryptophan as substrate, under the culturing conditions tested, despite demonstrating activity on N-methylated and 4-hydroxylated tryptophan derivatives individually. Taken together, this work expands upon the known substrates for TrpM and PsiD, further increasing the diversity of tryptamine biosynthetic products., (© 2024 The Author(s). Biotechnology Progress published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

Butyl butyrate is a short-chain fatty acid ester (C8) with a fruity aroma. It has broad prospects in the fields of foods, cosmetics and biofuels. At present, butyl butyrate is produced by chemical synthesis in the industry, but it is highly dependent on petroleum-based products. The growing concerns regarding the future scarcity of fossil fuels have been strongly promoted the transition from traditional fossil fuels and products to renewable bioenergy and biochemicals. Therefore, it is necessary to develop a green biochemical technology to replace traditional petroleum-based materials. In recent years, microorganisms such as Escherichia coli and Clostridium have been engineered to serve as cell factories for the sustainable one-pot production of short-chain fatty acid esters, including butyl butyrate. This opinion highlights the recent development in the use of lipases and alcohol acyltransferases (AATs) for butyl butyrate production in microbial fermentation, as well as future perspectives., (© 2024 The Author(s). Microbial Biotechnology published by John Wiley & Sons Ltd.)

Parametric optimization always plays important roles in bioengineering systems to obtain a high product yield under the proper conditions. The parametric conditions of lactic acid production by homologous batch fermentation of Lactobacillus pentosus cells was optimized by the Box-Behnken design. The highest l-lactic acid yield was obtained as 0.836 ± 0.003 g/g glucose with the productivity of 0.906 ± 0.003 g/(L × H) under the optimum conditions of 34.7 °C, pH 6.2, 148 rpm agitation speed, and 9.3 g/L nitrogen source concentration determined by quadratic response surface with high accuracy. The adequate kinetic models of cell growth rate, lactic production rate, and glucose consumption rate were also established to describe the fermentation behavior of L. pentosus cells with the correlation coefficients of 09985, 0.9990, and 0.9989, respectively., (© 2020 International Union of Biochemistry and Molecular Biology, Inc.)

Lignocellulose, one of the most abundant renewable sources of sugar, can be converted into bioenergy through hydrolysis of cellulose and hemicellulose. Due to its renewability and availability in large quantities, bioenergy is considered as a possible alternative to fossil energy and attracts the attention of the world with increased concerns about environmental protection and energy crisis. The depolymerization of cellulosic substrate to monomer is the rate-limiting step in the bioconversion of lignocellulose by cellulolytic microbes. Cellulosome, a multienzyme complex from anaerobic cellulolytic bacteria, can efficiently degrade the cellulosic substrates. Previous studies have shown that the reconstitution of cellulosome in vitro and its heterologous expression or display on the cell surface can help to solve the low yield problem of cellulosome in cellulolytic bacteria. This paper reviews the research progress in the reconstitution of cellulosome as well as its application in biorefinery, including the construction of cellulosome as well as different methods for cellulosome reconstitution and its surface display. This review will promote the understanding of cellulosome and its reconstitution., (© 2019 International Union of Biochemistry and Molecular Biology, Inc.)

When using a combination of pre-extraction and chemical pulping, a high yield of sugar recovery and minimal negative effect on the subsequent pulping step are expected. In this work, the P factor was utilized to investigate the effect of auto-hydrolysis severity on sugar recovery, removal of the main component, and impact on the kraft pulping of acacia wood chips. Using a P factor of 235, 84.34% of the polysaccharides in 14.05 g L -1 of dissolved sugars could be obtained. In addition, the soluble sugars were easily separated with a recovery yield of 3.54 g ·L -1 and Mw of 4,690 g mol -1 by direct precipitation using organic solvents. However, a maximum of 22.14 g L -1 of dissolved sugars was obtained with approximately 72.53% polysaccharides and Mw of 2,198 g mol -1 for a P factor of 601. Moreover, nearly 50% of the degraded carbohydrates remained in the auto-hydrolyzed wood chips. The decrease in the mass of pentosan, holocellulose, and klason lignin was 62, 30, and 8.76%, respectively. With intensifying severity, the screened yield and viscosity of pulps decreased markedly, whileas the Kappa number increased. No significant differences were observed in the morphology of the resultant fibers. Moreover, there was a decrease in the physical strength of the pulps due to the loss of the intrinsic strength of the pulp fibers, which in turn resulted from the cellulose damage. The combustion performance of the resultant pulping black liquor is improved due to the higher lignin content., (© 2019 American Institute of Chemical Engineers.)

This study investigated the impact of biomass-based fly ash (FA) pretreatment on the biodegradability of a thermomechanical pulping spent liquor (TMPL) in an aerobic system. In this study, FA was mixed with TMPL under the conditions of 6 wt.% based on TMPL, 25°C and 10 h, which removed a part of recalcitrant organic materials and resulted in 68.0, 40.0, 60.1, 81.2 and 48.3% reductions in chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), lignin and sugar, respectively. FA-pretreated TMPL pressate (FA-TMPL) was biologically treated in an aerobic system of sequencing batch reactor (SBR). The performance of the biological treatment with and without FA pretreatment was studied in two parallel SBRs over three months. The combination of FA and biological treatments removed 97.3% of COD, 98.3% of BOD, 96.3% of lignin, 99.5% of sugar, and 98.1% of TOC. Without FA pretreatment, the biological system removed 87.3% of COD, 89% of BOD, 81.6% of lignin, 98.6% of sugars, and 90.5% of TOC. The results also confirmed that the settling ability of sludge, which was indicated as a sludge volume index, was reduced from 109.3 mL/g to 53.5 mL/g. In addition, the advantages of using FA pretreatment in aerobic systems were discussed in detail. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:370-378, 2018., (© 2017 American Institute of Chemical Engineers.)

The main purpose of this study is to explore the sulfation of xylan to produce an anionic flocculant, sulfated xylan, for removing ethyl violet dye from simulated dye solutions. In this work, xylan was sulfated with chlorosulfonic acid in N, N-dimethylformamide solvent and the reaction conditions were optimized using a response surface methodology. It was observed that the maximum degree of substitution of 1.1 was obtained for sulfated xylan under the conditions of 3.71 chlorosulfonic acid/xylan molar ratio, 70°C and 7 h reaction time. The resulting sulfated xylan had a charge density of -3.12 mmol/g and molecular weight (M w ) of 22,300 g/mol. Furthermore, elemental and thermogravimetric analyses, Fourier transform infrared spectroscopy and proton nuclear magnetic resonance ( 1 H-NMR) confirmed the sulfation of xylan. The application of sulfated xylan as a flocculant for decolorizing the simulated ethyl violet dye wastewater was studied. The results indicated that 97% of dye was removed from 50 mg/L dye solution at the sulfated concentration of 175 mg/L and pH 9, but unmodified xylan was ineffective in flocculating and removing dye segments. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:529-536, 2018., (© 2018 American Institute of Chemical Engineers.)

Among the protease-producing bacterial strains isolated from deep-sea sediments, SWJS2 was finally selected and identified as genus Exiguobacterium. Plackett-Burman and orthogonal array designs were applied to optimize the fermentation conditions, and the results are as follows: Glucose 5g, yeast extract 15g, glycerin 2g and CaCl2 ⋅2H2 O 0.5 g dissolved in 1 L artificial seawater; temperature 25 °C, original pH 7, inoculum rate 2%, seed age 12 H, loading volume 25 mL (250-mL Erlenmeyer flask), shaking speed 150 rpm, and fermentation time 44 H. The protease activity production was improved from about 80 to 660 U/mL under the optimized parameters. The protease was purified fourfold with specificity activity of 30,654.1 U/mg protein and a total yield of 16.2%. The protease exhibited the maximum activity at 40-45 °C and pH 7. Moreover, the enzyme activity was found to be inhibited by Cu(2+) , Ba(2+) , Cd(2+) , Hg(2+) , and Al(3+) at 5 mM, whereas it can be increased by Mg(2+) , Mn(2+) , and Ca(2+) at 0.5-5 mM. The enzyme was totally inactivated by 1 or 5 mM ethylenediaminetetraacetic acid but not by phenylmethanesulfonyl fluoride, tyrpsin inhibitor from Glycine max (STI), benzamidine, 5,5'-dithio-bis-(2-nitro benzoic acid), or pepstatin A, suggesting that it belonged to metalloprotease., (© 2015 International Union of Biochemistry and Molecular Biology, Inc.)

Potato residue is vastly produced in the food industry but it is landfilled. This article describes the treatment of purified cellulose derived from potato residues by a high pressure homogenizer to produce nano-fibrillated cellulose (NFC), which was then oxidized by sodium periodate to prepare dialdehyde nano-fibrillated cellulose (DANFC). The produced NFC and DANFC were characterized by a scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The orthogonal experiment was induced to obtain the maximum degree of oxidation (DO) on DANFC. The results indicated that the optimal conditions were 40°C and pH 3. Alternatively, the isotherm and kinetic studies for the adsorption of creatinine on DANFC with different DOs (70.5 and 88.8%) were investigated, and the experimental results fitted well into Freundlich isotherm model and pseudo second-order kinetic model. The maximum adsorption capacities of DANFCs with the DO of 70.55 and 88.85% were 6.7 and 17.2 mg g(-1) , respectively, which were achieved under the conditions of 37°C and initial creatinine concentration of 100 mg L(-1)., (© 2015 American Institute of Chemical Engineers.)

Enzymatic synthesis of ascorbyl undecylenate, an unsaturated fatty acid ester of ascorbic acid, was reported with biomass-derived 2-methyltetrahydrofuran (MeTHF) as the cosolvent. Of the immobilized lipases tested, Candida antarctica lipase B (CAL-B) showed the highest activity for enzymatic synthesis of ascorbyl undecylenate. Effect of reaction media on the enzymatic reaction was studied. The cosolvent mixture, t-butanol-MeTHF (1:4, v/v) proved to be the optimal medium, in which not only ascorbic acid had moderate solubility, but also CAL-B showed a high activity, thus addressing the major problem of the solvent conflict for dissolving substrate and keeping satisfactory enzyme activity. In addition, the enzyme was much more stable in MeTHF and t-butanol-MeTHF (1:4) than in previously widely used organic solvents, t-butanol, 2-methyl-2-butanol, and acetone. The much higher initial reaction rate in this cosolvent mixture may be rationalized by the much lower apparent activation energy of this enzymatic reaction (26.6 vs. 38.1-39.1 kJ/mol) and higher enzyme catalytic efficiency (Vmax /Km , 8.4 vs. 1.3-1.4 h(-1) ). Ascorbyl undecylenate was obtained with the yields of 84-89% and 6-regioselectivity of >99% in t-butanol-MeTHF (1:4) at supersaturated substrate concentrations (60 and 100 mM) after 5-8 h., (© 2014 American Institute of Chemical Engineers.)