C1 Compounds Research Articles

Synthesis, Characterization, Antimicrobial Activity, DFT, Molecular Docking, and ADMET of 4-Chlorophenyazolquniolin-8-ol and Its Metal Complexes

In this study, we prepared 4-chlorophenylazoquinoline, a derivative of 8-hydroxyquinoline, with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions to create metal complexes. We used various physical and spectroscopic methods to characterize the compound and its metal complexes, including molar conductivity measurements, melting point analysis, elemental analysis, electronic absorption spectroscopy, mass spectrometry, magnetic resonance spectroscopy, infrared spectroscopy, and thermogravimetric analysis. The octahedral geometry of all prepared complexes has been confirmed. To assess the antimicrobial activity, we examined two types of bacterial strains and two types of fungal strains. The antimicrobial activity of the prepared compounds was observed, and the higher increase was observed in the copper complex. The compounds were studied computationally after optimizing the angles, lengths, and bonds using the basic set 6-31G(d,p)/LANL2DZ. The molecular docking study of the compounds with the Alzheimer's disease protein 4BDT showed significant activity in binding to the amino acids of HL, C1, C2, C3, C4, and C5 compounds, with affinity energies of -6.4, -6.9, -6.9, -6.7, and -7.2 kcal.mol-1 for the compounds, respectively. To evaluate the safety of the prepared compounds in different drug designs, we employed the ADMET study, reducing the risk of failure in advanced drug design stages. The results of the ADMET showed a relative decrease in the toxicity and carcinogenicity factor. However, there are indications of metabolic risk and cellular uptake, requiring further study.

Phytopathogenic Fungicidal Activity and Mechanism Approach of Three Kinds of Triphenylphosphonium Salts.

The triphenylphosphonium (TPP) cation has been widely used as a carrier for mitochondria-targeting molecules. We synthesized two commonly employed targeting systems, namely, ω-triphenylphosphonium fatty acids (group 2) and ω-triphenylphosphonium fatty alcohols (group 3), to assess the impact of the TPP module on the biological efficacy of mitochondria-targeting molecules. We evaluated their fungicidal activities against nine plant pathogenic fungi in comparison to alkyl-1-triphenylphosphonium compounds (group 1). All three compound groups exhibited fungicidal activity and displayed a distinct "cut-off effect", which depended on the length of the carbon chain. Specifically, group 1 compounds showed a cut-off point at C10 (compound 1-7), while group 2 and 3 compounds exhibited cut-off points at C15 (compound 2-12) and C14 (compound 3-11), respectively. Notably, group 1 compounds displayed significantly higher fungicidal activity compared to groups 2 and 3. However, group 2 and 3 compounds showed similar activity to each other, although susceptibility may depend on the pathogen tested. Initial investigations into the mechanism of action of the most active compounds suggested that their fungicidal performance may be primarily attributed to their ability to damage the membrane, as well as uncoupling activity and inhibition of fungal respiration. Our findings suggest that the TPP module used in delivery systems as aliphatic acyl or alkoxyl derivatives with carbon chains length < 10 will contribute negligible fungicidal activity to the TPP-conjugate compared to the effect of high level of accumulation in mitochondria due to its mitochondria-targeting ability. These results provide a foundation for utilizing TPP as a promising carrier in the design and development of more effective mitochondria-targeting drugs or pesticides.

Effects of foliar application of methyl jasmonate and/or urea, conventional or via nanoparticles, on grape volatile composition.

Viticulture has adapted foliar applications of biostimulants as a tool to improve crop quality. Recently, nanotechnology has been incorporated as a strategy to reduce the loss of biostimulants and treat nutrient deficiencies. Therefore, the present study aimed to investigate the effect of foliar applications of amorphous calcium phosphate nanoparticles (ACP) doped with methyl jasmonate (ACP-MeJA) and urea (ACP-Ur), individually or together (ACP-MeJA+Ur), on the content of volatile compounds in 'Tempranillo' grapes, compared to the conventional application of MeJA and Ur, individually or in combination (MeJA+Ur). The results showed that nanoparticle treatments reduced the total C6 compounds and some carbonyl compounds in the grape musts. This is of novel interest because their presence at high levels is undesirable to quality. In addition, some aroma-positive compounds such as nerol, neral, geranyl acetone, β-cyclocitral, β-ionone, 2-phenylethanal and 2-phenylethanol increased, despite applying MeJA and Ur at a lower dose. Consequently, although few differences in grape volatile composition were detected, nanotechnology could be an option for improving the aromatic quality of grapes, at the same time as reducing the required doses of biostimulants and generating more sustainable agricultural practices. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Hydrothermal recycling of polyolefins as potential alternative method for fuel production

The hydrothermal degradation of different polyolefins (virgin and recycled HDPE, recycled LLDPE, metallocene LLDPE, LDPE waste, virgin and recycled PP, PP waste) and their blends in different forms (granulate, foil) was investigated with supercritical water at 450 °C. The degradation of HDPE was investigated in a time range from 15 min to 240 min. The maximum yield of the oil phase was obtained at a degradation time of 60 min and was over 90 %, therefore all further experiments were carried out at a reaction time of 60 min. It was found that the composition of the oil obtained, and its calorific value depend on the type of material degraded. The oils obtained from PE materials contained between 65.3 % and 69.5 % saturated hydrocarbons, 11.4 %–17 % olefins and 8.9 %–20 % aromatics, while the oils from PP materials contained 40.8 %–45.9 % aromatics, 28.4 %–33.4 % saturated hydrocarbons and 10.6 % to 19.2% olefins. The main compounds in the oils from PP materials were the C9 compounds and from PE materials the C16 compounds. An exception were the oils from rLLDPE-1-g and LDPE-b, in which C8 compounds were most abundant and which contained the highest proportion of C17 – C31 hydrocarbons (approx. 17 %) compared to oils from other PE and PP materials (1.3 %–7.1 %). The HHV of the oils was between 29.4 and 45.7 MJ/kg and was highest for the oils where the gasoline/heavy oil ratio was less than 1, while the HHV of the gas phase was between 48.4 MJ/kg and 50.7 MJ/kg.

Model-based catalyst screening and optimal experimental design for the oxidative coupling of methane

The oxidative coupling of methane (OCM) to produce ethane and ethylene (C2 compounds) as platform chemicals involves complex chemistry with reactions both in the gas phase and on the catalyst surface, resulting in a distribution of products at the expense of C2 selectivity. This work uses experimental data from a variety of mixed metal oxides on supports at different reaction conditions (temperature, contact time, and reactant flow rates) to train a random forest regressor that predicts methane conversion and C2 selectivity (key performance indicators (KPIs)). The kinetically validated random forest models are deployed to locate optimal conditions that maximize C2 yield for each of the catalysts. Investigating the regressor interpretability via feature importance reveals that the choice of metals and support are crucial to C2 selectivity predictions in addition to the reaction conditions, while the predictions of methane conversion are largely governed by the reaction conditions. The machine learning (ML) regressor is used as a kinetic surrogate to find a locus of optimal reaction conditions that maximize both selectivity-conversion for each of the catalysts via a multi-objective optimization routine. The maximum C2 yields for catalysts are projected to be improved by 15% on average. Analyzing the catalysts with respect to a popular OCM catalyst, Mn-Na2WO4/SiO2, using the optimal locus eliminates variability in the process conditions to reveal distinct patterns based on intrinsic properties of metals and supports. Further, the decision space with catalyst descriptors and reaction conditions is optimized for high C2 yields using the ML surrogate, in a static multi-objective optimization routine, and an adaptive Bayesian routine, where the latter was found to have a wider field focus in proposing catalyst formulations and reaction conditions. Transition metal oxides on a variety of supports were proposed but not their lanthanide oxide counterparts. The framework has the potential to lend itself to materials acceleration platforms where it is crucial to consider multi-scale phenomena that impact downstream KPIs.

Unusual facet and co-catalyst effects in TiO2-based photocatalytic coupling of methane

Photocatalytic coupling of methane to ethane and ethylene (C2 compounds) offers a promising approach to utilizing the abundant methane resource. However, the state-of-the-art photocatalysts usually suffer from very limited C2 formation rates. Here, we report our discovery that the anatase TiO2 nanocrystals mainly exposing {101} facets, which are generally considered less active in photocatalysis, demonstrate surprisingly better performances than those exposing the high-energy {001} facet. The palladium co-catalyst plays a pivotal role and the Pd2+ site on co-catalyst accounts for the selective C2 formation. We unveil that the anatase {101} facet favors the formation of hydroxyl radicals in aqueous phase near the surface, where they activate methane molecules into methyl radicals, and the Pd2+ site participates in facilitating the adsorption and coupling of methyl radicals. This work provides a strategy to design efficient nanocatalysts for selective photocatalytic methane coupling by reaction-space separation to optimize heterogeneous-homogeneous reactions at solid-liquid interfaces.

Genetic engineering of a thermophilic acetogen, Moorella thermoacetica Y72, to enable acetoin production.

Acetogens are among the key microorganisms involved in the bioproduction of commodity chemicals from diverse carbon resources, such as biomass and waste gas. Thermophilic acetogens are particularly attractive because fermentation at higher temperatures offers multiple advantages. However, the main target product is acetic acid. Therefore, it is necessary to reshape metabolism using genetic engineering to produce the desired chemicals with varied carbon lengths. Although such metabolic engineering has been hampered by the difficulty involved in genetic modification, a model thermophilic acetogen, M. thermoacetica ATCC 39073, is the case with a few successful cases of C2 and C3 compound production, other than acetate. This brief report attempts to expand the product spectrum to include C4 compounds by using strain Y72 of Moorella thermoacetica. Strain Y72 is a strain related to the type strain ATCC 39073 and has been reported to have a less stringent restriction-modification system, which could alleviate the cumbersome transformation process. A simplified procedure successfully introduced a key enzyme for acetoin (a C4 chemical) production, and the resulting strains produced acetoin from sugars and gaseous substrates. The culture profile revealed varied acetoin yields depending on the type of substrate and culture conditions, implying the need for further engineering in the future. Thus, the use of a user-friendly chassis could benefit the genetic engineering of M. thermoacetica.

The Valorization of Spanish Minority Grapevine Varieties—The Volatile Profile of Their Wines as a Characterization Feature

Despite the large number of existing varieties of Vitis vinifera L., only few occupy a large niche in today’s highly globalized wine market. The increasing consumer demand for diversified products, as well as the changing climatic conditions, make establishing a process of varietal diversification essential to achieve both challenges. It is for this reason that the study of minority varieties, which have a higher level of adaptation to each area of origin, is of particular interest. With the main objective of achieving an in-depth knowledge of minority varieties in Spain, the national research project ‘Valorization of Minority Grapevine Varieties for their Potential for Wine Diversification and Resilience to Climate Change’ (MINORVIN), has been proposed. Within this extensive project, the present study describes the aroma profiles of 60 single-variety wines, corresponding with 44 different varieties, with 12 of these varieties being studied at the same time in several Spanish regions. Volatile compounds were determined through three consecutive vintages using gas chromatography-mass spectrometry (GC-MS) and gas chromatography–flame ionization detector (GC-FID). Compounds were grouped into major compounds, including alcohols, C6 compounds, esters, acetates, acids, carbonyl compounds, and other type of compounds, and minor compounds, including lactones, terpenes, and C13-norisoprenoids, according to their concentration in the wines being analyzed. Among this last group of compounds, lactones were quantitatively the most abundant, followed by terpenes. This study reflects that minority variety wines show distinctive aromatic profiles, supporting the importance of valuing and promoting the autochthonous minority grapevine varieties for the Spanish winemaking industry.

Chlamydomonas reinhardtii chloroplast factory construction for formate bioconversion

The photosynthetic autotrophic production of microalgae is limited by the effective supply of carbon and light energy, and the production efficiency is lower than the theoretical value. Represented by methanol, C1 compounds have been industrially produced by artificial photosynthesis with a solar energy efficiency over 10%, but the complexity of artificial products is weak. Here, based on a construction of chloroplast factory, green microalgae Chlamydomonas reinhardtii CC137c was modified for the bioconversion of formate for biomass production. By screening the optimal combination of chloroplast transport peptides, the cabII-1 cTP1 fusion formate dehydrogenase showed significant enhancement on the conversion of formate with a better performance in the maintenance of light reaction activity. This work provided a new way to obtain bioproducts from solar energy and CO2 with potentially higher-than-nature efficiency by the artificial-natural hybrid photosynthesis.

Effects of winemaking techniques on the volatile compounds of Chelva wines

This study aimed to investigate the impact of three winemaking techniques on the volatile compounds and sensory profile of La Mancha Chelva wines, including wine elaborated by traditional white winemaking process (CW), wine enzymatically treated (WE), wine from must with skin contact treatment (SCW) and wine aging on lees (WL). A total of 32 varietal aroma compounds and 44 volatile compounds formed principally during alcoholic fermentation were identified and quantified by GC-MS independently of the winemaking technique and vintage year. WE showed the highest contents of terpenes, C13-norisoprenoids and benzenic compounds, SCW displayed major concentrations of C6 compounds whereas WL exhibited the major concentrations of the principal groups of volatile compounds formed mainly during alcoholic fermentation. All wines showed the same sequence of aromatic series, with the highest aroma contribution being those of the fruity, sweet and fatty series. The differences found in volatile compounds modified the sensory aroma profile of CW enhanced the main attributes. These results reveal that the winemaking process used had an important effect on the volatile composition of Chelva wines and can be used for optimizing the elaboration method to ensure wines in concordance with consumer preferences and that preserved the distinctive aromatic typicity of Cheva wines.

Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst

Non-oxidative methane dehydro-aromatization reaction can co-produce hydrogen and benzene effectively on a molybdenum-zeolite based thermochemical catalyst, which is a very promising approach for natural-gas upgrading. However, the low methane conversion and aromatics selectivity and weak durability restrain the realistic application for industry. Here, a mechanism for enhancing catalysis activity on methane activation and carbon-carbon bond coupling has been found to promote conversion and selectivity simultaneously by adding platinum–bismuth alloy cluster to form a trimetallic catalyst on zeolite (Pt-Bi/Mo/ZSM-5). This bimetallic alloy cluster has synergistic interaction with molybdenum: the formed CH3* from Mo2C on the external surface of zeolite can efficiently move on for C-C coupling on the surface of Pt-Bi particle to produce C2 compounds, which are the key intermediates of oligomerization. This pathway is parallel with the catalysis on Mo inside the cage. This catalyst demonstrated 18.7% methane conversion and 69.4% benzene selectivity at 710 °C. With 95% methane/5% nitrogen feedstock, it exhibited robust stability with slow deactivation rate of 9.3% after 2 h and instant recovery of 98.6% activity after regeneration in hydrogen. The enhanced catalytic activity is strongly associated with synergistic interaction with Mo and ligand effects of alloys by extensive mechanism studies and DFT calculation.

Assembling bifunctional ceria-zirconia electrocatalyst for efficient electrochemical conversion of methane at room temperature

The electrochemical conversion of methane to C2 compounds at room temperature is reported using CeO2-ZrO2 electrocatalysts. The mixed oxide electrocatalysts produced methanol, ethanol, and acetone, along with traces of acetaldehyde and isopropanol, under a polarization of 1.2 V with ∼ 50 % Faradaic efficiency. Detailed characterization of the CeO2-ZrO2 revealed the formation of nanoparticles (7–9 nm mean size) composed of ceria-zirconia solid solution or a mixture of ceria with both tetragonal and monoclinic zirconia polymorphs depending on the assembling configuration of the electrocatalyst. Samples with separated phases and limited solid solution formation showed the highest electrochemical activity, indicating that an optimal assembly of ceria and zirconia was crucial to achieving efficient conversion with high Faradaic efficiency and selectivity. Such high electrochemical activity observed for the phase separated CeO2-ZrO2 electrocatalyst suggests that a synergic effect between ceria and zirconia is required for the critical reaction steps, such as the activation and partial oxidation of methane. The experimental results point to credible routes to efficiently convert methane into valuable chemicals in mild conditions.

Structural, mechanical and electronic properties and phase transitions in superhard BC1-xNx: A first-principles study

First-principles investigations of the stability, mechanical properties, electronic and phonon structures, as well as molecular dynamics simulations of temperature- and pressure-induced phase transitions in boron carbonitrides, BC1-xNx, for x = 1.0 (C0), 0.75 (C1), 0.5 (C2), 0.25 (C3) and 0.0 (C4), were carried out. The plausible mechanisms of the phase transitions in BNs were proposed and the transformation paths were established for the h → w, r → c, c → r and w → h’ transitions, where h’ was the new hP4-187 phase (space group P-6m2, #187). The non-layered C0–C3 compounds transformed into the layered ones at 2000–3000 K. The new BC1-xNx structures are brittle materials and exhibit the best combination of hardness (23.1–60.8 GPa) and fracture toughness (4.03–5.23 MPa m1/2). The C1–C4 structures are metallic, except for three compounds: C1-oP8-25 and C4-tP8-136 are semi-metals, and C4-mP8-10 is a semiconductor with a very narrow bandgap of 0.2 eV.

Simultaneous determination of seawater trimethylamine and methanol by purge and trap gas chromatography using dual nitrogen-phosphorus detector and flame-ionization detector

Compounds containing one carbon atom or no carbon-carbon bond (C1 compounds), such as trimethylamine and methanol, are important climate relevant gases in the atmosphere and play key roles in global warming. The ocean is a significant source or sink of such compounds, while the concentrations of trimethylamine and methanol in seawater remain largely unconstrained due to the analytical challenges involved. Therefore, it is necessary to establish a continuous, rapid and sensitive method for the determination of these compounds with high polarity, volatility or solubility at low seawater concentrations. Here we developed a purge and trap system, coupled to a gas chromatography equipped with dual nitrogen phosphorus detector (NPD) and flame ionization detector (FID) for the simultaneous online analysis of trimethylamine and methanol at nanomolar range using a small sample volume (~ 10 mL). The dual detection of trimethylamine and methanol with NPD or FID was achieved by installing a capillary flow splitter between the capillary column and detectors. After modification and optimization of the setup and conditions, excellent linearity (R2 &amp;gt; 0.99) and repeatability (&amp;lt; 6%) were obtained for both compounds; the detection limits for trimethylamine and methanol were 0.3 nM and 17.6 nM, respectively. Using this method, water samples collected from coastal and open ocean were analyzed; trimethylamine and methanol concentrations ranged from 0.6 to 18.8 nM and 26.0 to 256.2 nM, respectively. Collectively, this method allowed for online, rapid, sensitive and simultaneous quantification of trace trimethylamine and methanol concentrations with low-cost instrumentation and small sample volume, which makes it promising for further application in volatile compounds analysis in marine environments.

Zeolite-assisted acid hydrolysis of cellulose: Optimization of reaction conditions and chemical pretreatments for enhancing HMF yields

This study explores the hydrolysis of microcrystalline cellulose under soft conditions using a combination of both homogeneous (HCl) and heterogeneous catalysts (β-zeolite). The impact of temperature and HCl concentration is studied, revealing that the most favorable results (highest HMF yield) are achieved at 140ºC with 0.02 %w/w of HCl (19% of selectivity, 23.5% of conversion). Nevertheless, the inherent recalcitrance of cellulose limits the conversion and the HMF concentration. Three chemical pretreatments (HCl, H2O2, HNO3) are considered, assessing the effect of concentration. Except when using 69% of HNO3, the bulk structure of cellulose remains largely unaffected (low effect on conversions). However, the surface of cellulose undergoes chemical alteration due to the acidic and predominantly oxidizing pretreatment, leading to the detection of C5 compounds. These modifications have a positive influence on the reaction, significantly enhancing the selectivity towards HMF up to 50% (34% of conversion).

A genetic toolbox to empower Paracoccus pantotrophus DSM 2944 as a metabolically versatile SynBio chassis

BackgroundTo contribute to the discovery of new microbial strains with metabolic and physiological robustness and develop them into successful chasses, Paracoccus pantotrophus DSM 2944, a Gram-negative bacterium from the phylum Alphaproteobacteria and the family Rhodobacteraceae, was chosen. The strain possesses an innate ability to tolerate high salt concentrations. It utilizes diverse substrates, including cheap and renewable feedstocks, such as C1 and C2 compounds. Also, it can consume short-chain alkanes, predominately found in hydrocarbon-rich environments, making it a potential bioremediation agent. The demonstrated metabolic versatility, coupled with the synthesis of the biodegradable polymer polyhydroxyalkanoate, positions this microbial strain as a noteworthy candidate for advancing the principles of a circular bioeconomy.ResultsThe study aims to follow the chassis roadmap, as depicted by Calero and Nikel, and de Lorenzo, to transform wild-type P. pantotrophus DSM 2944 into a proficient SynBio (Synthetic Biology) chassis. The initial findings highlight the antibiotic resistance profile of this prospective SynBio chassis. Subsequently, the best origin of replication (ori) was identified as RK2. In contrast, the non-replicative ori R6K was selected for the development of a suicide plasmid necessary for genome integration or gene deletion. Moreover, when assessing the most effective method for gene transfer, it was observed that conjugation had superior efficiency compared to electroporation, while transformation by heat shock was ineffective. Robust host fitness was demonstrated by stable plasmid maintenance, while standardized gene expression using an array of synthetic promoters could be shown. pEMG-based scarless gene deletion was successfully adapted, allowing gene deletion and integration. The successful integration of a gene cassette for terephthalic acid degradation is showcased. The resulting strain can grow on both monomers of polyethylene terephthalate (PET), with an increased growth rate achieved through adaptive laboratory evolution.ConclusionThe chassis roadmap for the development of P. pantotrophus DSM 2944 into a proficient SynBio chassis was implemented. The presented genetic toolkit allows genome editing and therewith the possibility to exploit Paracoccus for a myriad of applications.

VOC emissions from Euro 6 vehicles

BackgroundAir pollution is a major health concern in worldwide. Non-methane volatile organic compounds (NMVOCs) are precursors of secondary air pollutants, with road transport being responsible of ~ 90% for the EU-27’s NMVOCs transport emissions in 2021. A series of VOC emissions from 17 modern gasoline, Diesel and Plug-in hybrid (PHEV) vehicles were investigated under various driving conditions and temperatures. All tested vehicles meet the latest European emission standard (Euro 6d and Euro 6d-TEMP). The different VOC species were measured with a Fourier-Transform Infrared Analyzer (FTIR).ResultsDiesel vehicles presented the lowest VOC emissions, while PHEVs operating in charge sustaining mode, with a depleted battery, exhibited very similar behavior to conventional gasoline. Among the VOCs, C5 compounds were the primary contributors to total NMVOCs over WLTC at 23 °C for gasoline and PHEV vehicles. A proportional increase in VOC emissions at colder temperatures, affecting all the studied species, was observed. Significant increases were observed for Aromatics, with an important contribution of < C5 as well. On the other hand, VOC emissions from Diesel vehicles were consistently low and little affected by temperature, except for Aldehydes in tests at − 7 °C. VOC emissions primarily occurred during cold starts, with urban cycle showing higher emission factors due to its shorter distance. VOC emissions remained consistently low during the highway cycle, highlighting a significant reduction in VOC emissions once the after-treatment system (ATS) was warmed up, even under demanding conditions. In Diesel vehicles, total VOCs measured with the FTIR exhibited a slight tendency to exceed Total Hydrocarbons (THC) measured with a Flame Ionization Detector (FID), while for gasoline vehicles and PHEVs, the trend was temperature-dependent.ConclusionsIn summary, the study shows that VOC emissions from Diesel vehicles are significantly lower compared to modern gasoline and PHEV vehicles. Moreover, gasoline and PHEV vehicles exhibit similar levels and emission profiles of VOC emissions. Additionally, ambient temperatures and driving conditions have a significant impact on VOC emissions for all the powertrain technologies investigated.

Photoregulation of the biosynthetic activity of the edible medicinal mushroom Lentinula edodes in vitro.

The findings of the study demonstrate the impact of low-intensity laser and quasi-monochromatic light on the biosynthetic activity of the edible medicinal fungus L. edodes during submerged cultivation. An artificial lighting installation based on matrices of light-emitting diodes (LED) emitting light at 470nm (blue), 530nm (green), 650nm (red), and argon gas laser (488nm) was used. Irradiation with blue and red LED and laser led to a shortening of the lag phase by 2days and an increase in the mycelial mass. Irradiation with laser light resulted in the highest mycelial mass yield (14.1g/L) on the 8th day of cultivation. Irradiation in all used wavelength ranges caused an increase in the synthesis of both extracellular and intracellular polysaccharides. Laser light at 488nm and LED at 470nm proved to be the most effective. Irradiation with red, green, and blue laser light caused an increase in the total amount of fatty acids in the mycelial mass compared to the control. A significant distinction in qualitative composition was observed: short-chain acids C6‒C12 compounds were produced under red light irradiation, whereas long-chain C20‒C24 were formed under green light irradiation. The most significant changes in the aromatic profile of the mycelial mass and culture liquid were recorded upon irradiation with green light. The content of aromatic components increased 24.6 times in the mycelial mass and 38.5 times in the culture liquid. The results suggest the possibility of using low-intensity quasi-monochromatic light for targeted regulation of L. edodes biosynthetic activity.

Metabolite cross-feeding enables concomitant catabolism of chlorinated methanes and chlorinated ethenes in synthetic microbial assemblies.

Isolate studies have been a cornerstone for unraveling metabolic pathways and phenotypical (functional) features. Biogeochemical processes in natural and engineered ecosystems are generally performed by more than a single microbe and often rely on mutualistic interactions. We demonstrate the rational bottom-up design of synthetic, interdependent co-cultures to achieve concomitant utilization of chlorinated methanes as electron donors and organohalogens as electron acceptors. Specialized anaerobes conserve energy from the catabolic conversion of chloromethane or dichloromethane to formate, H2, and acetate, compounds that the organohalide-respiring bacterium Dehalogenimonas etheniformans strain GP requires to utilize cis-1,2-dichloroethenene and vinyl chloride as electron acceptors. Organism-specific qPCR enumeration matched the growth of individual dechlorinators to the respective functional (i.e. dechlorination) traits. The metabolite cross-feeding in the synthetic (co-)cultures enables concomitant utilization of chlorinated methanes (i.e. chloromethane and dichloromethane) and chlorinated ethenes (i.e. cis-1,2-dichloroethenene and vinyl chloride) without the addition of an external electron donor (i.e. formate and H2). The findings illustrate that naturally occurring chlorinated C1 compounds can sustain anaerobic food webs, an observation with implications for the development of interdependent, mutualistic communities, the sustenance of microbial life in oligotrophic and energy-deprived environments, and the fate of chloromethane/dichloromethane and chlorinated electron acceptors (e.g. chlorinated ethenes) in pristine environments and commingled contaminant plumes.

Heterologous production of 3-hydroxypropionic acid in Methylorubrum extorquens by introducing the mcr gene via a multi-round chromosomal integration system based on cre-lox71/lox66 and transposon

Background and aimReprogramming microorganisms to enhance the production of metabolites is a part of contemporary synthetic biology, which relies on the availability of genetic tools to successfully manipulate the bacteria. Methylorubrum extorquens AM1 is a platform microorganism used to convert C1 compounds into various value-added products. However, the repertoire of available plasmids to conveniently and quickly fine-tune the expression of multiple genes in this strain is extremely limited compared with other model microorganisms such as Escherichia coli. Thus, this study aimed to integrate existing technologies, such as transposon-mediated chromosomal integration and cre-lox-mediated recombination, to achieve the diversified expression of target genes through multiple chromosomal insertions in M. extorquens AM1.ResultsA single plasmid toolkit, pSL-TP-cre-km, containing a miniHimar1 transposon and an inducible cre-lox71/lox66 system, was constructed and characterized for its multiple chromosomal integration capacity. A co-transcribed mcr-egfp cassette [for the production of 3-hydroxypropionic acid (3-HP) and a reporting green fluorescent protein] was added to construct pTP-cre-mcr-egfp for evaluating its utility in mediating the expression of heterologous genes, resulting in the production of 3-HP with a titer of 34.7–55.2 mg/L by two chromosomal integration copies. Furthermore, in association with the expression of plasmid-based mcr, 3-HP production increased to 65.5–92.4 mg/L.ConclusionsThis study used a multi-round chromosomal integration system based on cre-lox71/lox66 and a transposon to construct a single constructed vector. A heterologous mcr gene was introduced through this vector, and high expression of 3-hydroxypropionic acid was achieved in M. extorquens. This study provided an efficient genetic tool for manipulating M. extorquens, which not only help increase the expression of heterologous genes in M. extorquens but also provide a reference for strains lacking genetic manipulation vectors.