Yield Of Target Product Research Articles

Lignin valorization to bioplastics with an aromatic hub metabolite-based autoregulation system

Exploring microorganisms with downstream synthetic advantages in lignin valorization is an effective strategy to increase target product diversity and yield. This study ingeniously engineers the non-lignin-degrading bacterium Ralstonia eutropha H16 (also known as Cupriavidus necator H16) to convert lignin, a typically underutilized by-product of biorefinery, into valuable bioplastic polyhydroxybutyrate (PHB). The aromatic metabolism capacities of R. eutropha H16 for different lignin-derived aromatics (LDAs) are systematically characterized and complemented by integrating robust functional modules including O-demethylation, aromatic aldehyde metabolism and the mitigation of by-product inhibition. A pivotal discovery is the regulatory element PcaQ, which is highly responsive to the aromatic hub metabolite protocatechuic acid during lignin degradation. Based on the computer-aided design of PcaQ, we develop a hub metabolite-based autoregulation (HMA) system. This system can control the functional genes expression in response to heterologous LDAs and enhance metabolism efficiency. Multi-module genome integration and directed evolution further fortify the strain’s stability and lignin conversion capacities, leading to PHB production titer of 2.38 g/L using heterologous LDAs as sole carbon source. This work not only marks a leap in bioplastic production from lignin components but also provides a strategy to redesign the non-LDAs-degrading microbes for efficient lignin valorization.

Highly dispersed palladium supported on sulfuric acid-modified activated carbon for efficient dehydrogenation to produce novel aromatic monomer

Herein, a sustainable route to novel aromatic monomer, dimethyl 1,2,3,4-tetrahydro-1,4-methanonaphthalene-5,8-dicarboxylate, was developed, in which dimethyl muconate and norbornene used as the diene and dienophile undergo Diels-Alder reaction followed by dehydrogenation. The polycyclic cycloadduct, octahydro-1,4-methanonaphthalene-5,8-dicarboxylate, could be synthesized without catalyst. The activated carbon modified with sulfuric acid generated more oxygen-containing groups, stronger acidity and more acidic sites. Highly dispersed palladium metal particles with an average particle size of about 1.0 nm exhibited excellent activity in the dehydrogenation reaction and the yield of target product reached 73.8 %.

Micro-mesoporous carbons form non-porous zinc-organic coordination compounds: Synthesis, structure and gas adsorption properties

A series of non-porous zinc-containing coordination compounds with mono- and polydentate ligands has been used to produce carbon materials with a hierarchical porous structure. Adjustment of the carbonization mode enables to increase the target product yield by an average of three times. The obtained carbons have a combination of micro- and mesopores with a pronounced maximum at 3.5 nm. The gas-sorption behavior of the obtained carbons has been studied over a wide range of temperatures and pressures. It has been established that the amount of excess adsorption for hydrogen and methane reaches 2.7 and 15 wt%, respectively. The extension of the proposed approach to the use of simple bimetallic complexes as precursors may be promising for obtaining effective catalysts based on a carbon matrix with controlled porosity and encapsulated nanoscale particles of a catalytically active metal.

Lewis acid-catalyzed chemo- and stereoselective addition of pyrroles to skipped diynones: en route to novel pyrrole-based ketocyanine dyes and alkyne-tethered enones

The first chemo- and stereoselective syntheses of hitherto unknown pyrrole-based β,β′-disubstituted ketocyanine dyes and alkyne-tethered enones through Lewis acid-catalyzed addition of pyrroles to skipped diynones (penta-1,4-diyn-3-ones) are described. The protocols feature a good substrate tolerance, mild reaction conditions, and high yields of target products. A wide synthetic utility of synthesized alkyne-tethered enones as novel building blocks is demonstrated by the synthesis of diverse pyrrole-containing compounds. The UV–vis absorption properties for selected representatives of novel adducts are studied to preliminary access their potential as photoinitiators/sensitizers in visible light induced polymerization.

Acquisition of para-(1-methylcyclopentyl)phenol and its acylation reaction with acetyl- and benzoyl chlorides

The article is devoted to the study of phenol cycloalkylation reactions 1-methylcyclopentene in a in periodical action installation in the presence of zeolite-containing catalyst KN-30 and acylation reactions of obtained p-(1-methylcyclopentyl)phenol with acetyl and benzoyl chlorides in the presence of a ZnCl2 catalyst. First of all, the influence kinetic parameters (temperature, time, molar ratios starting components, the amount of catalyst) on the yield and selectivity reactions of cycloalkylation of phenol with 1-methylcyclopentene in the presence of catalyst KN-30 was investigated. In the found optimal conditions for the cycloalkylation reaction: temperature – 110 оС, time – 5 hours, molar ratio of phenol to MCF 1:1, amount of catalyst 12 %, yield of the target product – p-(1-methylcyclopentyl)phenol is 77.3 % (based on phenol), the selectivity of the target product is 92.6 %. Acylation reactions of the obtained p-(1-methylcyclopentyl)phenol with acetyl- and benzoyl chlorides were performed in the presence of anhydrous catalyst ZnCl2. In order to obtain effective conditions for acylation reactions, the influence of the reaction temperature, duration, and molar ratio of the starting components on the yield and selectivity of methylcyclopentylaceto- and benzophenones was studied. As a result, it was found that for acylation reactions of p-(1-methylcyclopentyl)phenol with acetyl and benzoyl chloride in the presence of a ZnCl2 catalyst, the reaction temperature is 140–150 оC, the duration should be 35–40 minutes, and the molar ratio phenol AC(BC) should be 1:2. Under these conditions, the yield of target products is 57.2–61.7 % (based on the taken alkylphenol).

The sustainable microwave approach to H2S and RSH activation into Di- and Trisulfides in N-Methylpyrrolidone

A reagent- and waste-free method for the transformation of hydrogen sulfide and thiols with С3-С8 hydrocarbons groups into value-added di- and trisulfides is proposed under the microwave irradiation. The hydrogen sulfide solution in N-methylpyrrolidone was used as the reaction medium to occur the interaction with different thiols. The influence of the microwave irradiation power, duration, the temperature and thiol structure on the yield and ratio of target products has been investigated. It is found that the effective microwave power for activation of H2S and RSH should be at least 200 W, while increasing the reaction temperature reduces the contact time. The maximum values for the yield of di- and trisulfides were obtained at 280 W and 100 °C. High selectivity of trisulfide formation was observed in the case of alkanethiols C3-C5, especially for compounds with isomeric hydrocarbons groups. Differences in the mechanisms of H2S interaction with linear and branched thiols based on the formation of alkylhydropolysulfide intermediates have been identified. The proposed scheme of utilization of H2S and low-molecular-weight thiols into organic polysulfides under microwave irradiation was suggested.

Carbon-supported hydroxyapatite hybrid catalysts for butan-1-ol conversion: Effect of the nature of carbon support on process selectivity

Hybrid systems of hydroxyapatite supported on carbonaceous materials of different nature (activated charcoals, acetylene black, carbon black, graphite flake, synthesized microporous and mesoporous carbons) are investigated as catalysts for vapor-phase Guerbet condensation of butan-1-ol. The structure, morphology, and acid–base characteristics of hydroxyapatite, carbon supports, and the hybrid systems have been characterized by XRD, SEM-EDX, low-temperature (77 K) nitrogen ad(de)sorption, NMR, XPS, EPR, Raman spectroscopy, and TPD-NH3/CO2 techniques. The butan-1-ol conversion and selectivity towards the reaction products are found to be highly dependent on carbonaceous supports of the hybrid catalysts. The important role of acid–base capacity ratio is highlighted to achieve high selectivity in vapor-phase Guerbet condensation of butan-1-ol to 2-ethylhexan-1-ol. In particular, the surface’s strong basic sites are preferable for elongating the carbon chain. The high selectivity towards 2-ethylhexan-1-ol of about 75% is achieved over HAP/graphite flake and up to 57% over HAP/activated coconut charcoal. Compared to the bulk hydroxyapatite, the enhanced performance of the hybrid catalysts (initial activity and target product yield) is associated with the redistribution of active sites over carbon supports by strength and location.

Competition between biodetoxification fungus and lactic acid bacterium in the biorefinery processing chain for production of cellulosic L-lactic acid

Biodetoxification fungus selectively degrades toxic inhibitors generated from pretreatment of lignocellulose without consuming fermentable sugars. However, one barrier for practical application is the sustained cell viability in the consequent fermentation step to compete the fermentable sugars with fermenting strains, resulting in sugar loss and reduced target product yield. This study investigated the competitive growth property between the biodetoxification fungus Paecilomyces variotii FN89 and the L-lactic acid bacterium Pediococcus acidilactici ZY271 under varying temperature and lactic acid osmatic stress. The results show that the L-lactic acid bacterium Ped. acidilactici ZY271 showed less thermotolerance to Pae. variotii FN89 at high temperature of 45 °C to 50 °C in both synthetic medium and wheat straw hydrolysate. In the higher temperature environment, the growth of the biodetoxification strian failed to compete with the lactic acid fermentation strain and was quickly eliminated from the fermentation system. The high temperature fermentation facilitated a fast transition from the detoxification stage to the fermentation stage for higher production of L-lactic acid.

Prediction of catalytic cracking performance during co-processing of vacuum gas oil and low-margin oil refining streams

Relevance. Expansion of catalytic cracking feedstock resources both due to the need to intensify the process to increase the yield of target products (high-octane gasoline, light olefins) and to deepen oil refining through the utilization of low-margin streams at refineries. Along with this, there is an urgent need to develop domestic mathematical tools for optimizing the catalytic cracking, predicting the process performance when the modes and feedstock qualities changes, as well as planning of production. This requires in-depth analysis and detailed study of the composition of oil fractions involved in processing and thermodynamics and kinetics of a heterogeneous process. The development and application of a mathematical model of the catalytic cracking, taking into account the composition and properties of the components involved in processing, makes it possible to quantitatively assess the yield and quality of target and by-products depending on the composition, physicochemical properties of the mixed feedstock, and the parameters of the technological regime, with an assessment of the possibility of their processing at an existing industrial facility. Aim. Experimental study of the composition and properties of mixed feedstock of catalytic cracking based on vacuum gas oil containing 5 to 20 wt % of extract of selective cleaning of oils, distillate, residual slack wax, and deasphalted oil, and prediction of the catalytic cracking indicators during their co-processing using a mathematical model. Methods. Liquid chromatography method to study the composition of feedstock materials of the catalytic cracking in combination with a number of standard methods for determining physico-chemical properties. Results. Using a set of experimental studies, the authors have established the patterns of changes in the composition and physico-chemical properties of the components and mixed feedstock of catalytic cracking containing 5–20 wt % of distillate and residual slack wax, deasphalted oil, and extract. The results obtained were used in development of a mathematical model of the heterogeneous catalytic cracking of feedstock, which takes into account the composition of oil fractions involved in processing and the patterns of catalyst deactivation by coke. Using a mathematical model, the authors established the patterns of changes in the composition and yield of process products when 5–20 wt % were involved in processing distillate slack wax and extracts of selective cleaning of oils mixed with vacuum distillate. Practical recommendations were developed on the possibility of expanding the hydrocarbon feedstock of the catalytic cracking, taking into account the fuel or petrochemical regime.

Co-pyrolysis of low-rank coal and rice stalk: A comprehensive study on product distributions, product properties, and synergistic effects

Co-pyrolysis of low-rank coal and rice stalk is an important way to achieve hierarchical and efficient utilization of energy. This work explored how blend ratios (0–100 wt%) and temperatures (773–1073 K) affect pyrolysis product distribution and characteristics. The results showed that a higher rice straw ratio (80 wt%) significantly reduced the yield of char (22.38–26.9 wt%) compared with 20 wt% of rice straw at different temperatures. The yield and physicochemical properties of target products were closely related to process parameters, which can provide a promising opportunity to acquire desired products by reaction conditions optimization. Co-pyrolysis was able to inhibit the production of large aromatic ring structures in char. High temperature promoted the generation of cross-linked structures, which was influenced by the blend ratio. The synergistic effects of BET surface area and pore volume were most pronounced when the J content was 40 wt% at 873 K, and their increments were 59.6 m2/g and 0.027 cm3/g, respectively. For the char derived from lower rice straw proportions (0, 20, and 40 wt%), the main combustion range and the maximum combustion rate temperature showed a progressive shift towards higher values with temperature increasing. The research is valuable of guiding high-value utilization of agricultural residues and energy transitions.

РАЗРАБОТКА МЕТОДА СИНТЕЗА ТРИГЛИЦЕРИДА КАПРОНОВОЙ КИСЛОТЫ ДЛЯ БИОДИЗЕЛЯ

Among the known triglycerides are low molecular weight triacylglycerols, in particular tricaproins, which are an internal marker of vegetable oils and animal fats used to produce biodiesel for agricultural needs. However, there are no simple and accessible methods for the synthesis of tricaproins in high yields in the literature, since the preparation of this compound is often accompanied by the following problems: tarring of the reaction mass, deactivation of the catalyst, low conversion of the starting reagents, loss of the starting reagents due to the formation of emulsions and side compounds. An accessible selective method for producing caproic acid triglyceride with high yield has been developed, the main and side reactions of the synthesis have been studied, the reaction parameters and optimal conditions for the synthesis of the target product have been determined. The work studied various temperature, concentration, time factors and catalysts that affect the yield of caproic acid triglyceride through the esterification reaction of glycerol with caproic acid. The highest yield and conversion of the target product was achieved based on the catalytic interaction of caproic acid with glycerol in the presence of 3 wt% 85% orthophosphoric acid and 5 wt% silicon tripolyphosphate cocatalyst under vacuum. The structure of the resulting tricaproin was confirmed by NMR, mass spectrometry and IR spectroscopy. The pure product is obtained in the form of a transparent thick liquid of light orange or slightly red color. The yield of the final target product is 95%.

Batch fermentation kinetics study of biosynthesis lipopeptides by Bacillus altitudinis Q7 in 5 L fermenter

Optimization of fermentation parameters can effectively increase microbial metabolites. The fermentation conditions of biosynthesis lipopeptides by Bacillus altitudinis Q7 (B. altitudinis Q7) in 5 L reactor were optimized and the fermentation kinetics were monitored throughout the fermentation process. By design-response surface methodology, the results showed that under optimal conditions (72 h, pH 6.6, 31 °C, 3% inoculum, 200 rpm, 1.5 L/min aeration), the lipopeptide yield reached 1.689 mg/mL, 24.5% higher than under single-factor conditions, with maximum biomass dry weight of 1.650 g/L. According to the logistic and Luedeking-Piret approximate models, kinetic equation models of growth, product (lipopeptide) synthesis, and substrate (glucose) utilization during the fermentation process were simulated. This was done to fit variables and devise optimal control strategies. The research has improved the yield of target products in fermentation processes, reduced production costs and provided a theoretical basis for the simulation, optimisation and regulation of fermentation in modern industry.

Characterization of Three Types of Elongases from Different Fungi and Site-Directed Mutagenesis.

Fatty acid elongases play crucial roles in synthesizing long-chain polyunsaturated fatty acids. Identifying more efficient elongases is essential for enhancing oleaginous microorganisms to produce high yields of target products. We characterized three elongases that were identified with distinct specificities: McELO from Mucor circinelloides, PrELO from Phytophthora ramorum, and PsELO from Phytophthora sojae. Heterologous expression in Saccharomyces cerevisiae showed that McELO preferentially elongates C16 to C18 fatty acids, PrELO targets Δ6 polyunsaturated fatty acids, and PsELO uses long chain saturated fatty acids as substrates. McELO and PrELO exhibited more homology, potentially enabling fatty acid composition remodeling and enhanced LC-PUFAs production in oleaginous microorganisms. Site-directed mutagenesis of conserved amino acids across elongase types identified residues essential for activity, supported by molecular docking. Alanine substitution of conserved polar residues led to enzyme inactivation, underscoring their importance in the condensation reaction. Our findings offer promising elongase candidates for polyunsaturated fatty acid production, contributing to the bioindustry's sustainable development.

Rewiring Metabolic Flux in Corynebacterium glutamicum Using a CRISPR/dCpf1-Based Bifunctional Regulation System.

Corynebacterium glutamicum, a microorganism classified as generally recognized as safe for use in the industrial production of food raw materials and additives, has encountered challenges in achieving widespread adoption and popularization as microbial cell factories. These obstacles arise from the intricate nature of manipulating metabolic flux through conventional methods, such as gene knockout and enzyme overexpression. To address this challenge, we developed a CRISPR/dCpf1-based bifunctional regulation system to bidirectionally regulate the expression of multiple genes in C. glutamicum. Specifically, through fusing various transcription factors to the C-terminus of dCpf1, the resulting dCpf1-SoxS exhibited both CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) capabilities in C. glutamicum by altering the binding sites of crRNAs. The bifunctional regulation system was used to fine-tune metabolic flux from shikimic acid (SA) and l-serine biosynthesis, resulting in 27-fold and 10-fold increases in SA and l-serine production, respectively, compared to the original strain. These findings highlight the potential of the CRISPR/dCpf1-based bifunctional regulation system in effectively enhancing the yield of target products in C. glutamicum.

Oxidative chlorination of hydrocarbons. Part 1. The Deacon reaction. Oxidative chlorination of saturated hydrocarbons C1 and C2

The review paper considers main regularities of the hydrogen chloride oxidation (the Deacon reaction) and oxidative chlorination of methane and ethane. The most efficient catalysts for these processes were shown to be the copper chloride systems on various supports, which contain also chlorides of alkaline and rare-earth metals that decrease the carry-over of the active phase from the catalyst surface and increase the activity. The main kinetic and technological regularities of the oxychlorination processes were considered. The conditions that promote an increase in the yield of target products – lower chloromethanes at oxychlorination of methane and vinyl chloride at oxychlorination of ethane – were revealed. Variants of technological schemes for the oxychlorination processes were proposed.

Systemic metabolic engineering of Enterobacter aerogenes for efficient 2,3-butanediol production

2,3-Butanediol (2,3-BDO) is an important gateway molecule for many chemical derivatives. Currently, microbial production is gradually being recognized as a green and sustainable alternative to petrochemical synthesis, but the titer, yield, and productivity of microbial 2,3-BDO remain suboptimal. Here, we used systemic metabolic engineering strategies to debottleneck the 2,3-BDO production in Enterobacter aerogenes. Firstly, the pyruvate metabolic network was reconstructed by deleting genes for by-product synthesis to improve the flux toward 2,3-BDO synthesis, which resulted in a 90% increase of the product titer. Secondly, the 2,3-BDO productivity of the IAM1183-LPCT/D was increased by 55% due to the heterologous expression of DR1558 which boosted cell resistance to abiotic stress. Thirdly, carbon sources were optimized to further improve the yield of target products. The IAM1183-LPCT/D showed the highest titer of 2,3-BDO from sucrose, 20% higher than that from glucose, and the yield of 2,3-BDO reached 0.49 g/g. Finally, the titer of 2,3-BDO of IAM1183-LPCT/D in a 5-L fermenter reached 22.93 g/L, 85% higher than the wild-type strain, and the titer of by-products except ethanol was very low.Key pointsDeletion of five key genes in E. aerogenes improved 2,3-BDO productionThe titer of 2,3-BDO was increased by 90% by regulating metabolic fluxResponse regulator DR1558 was expressed to increase 2,3-BDO productivityGraphical abstract

Advances in Droplet-Based Microfluidic High-Throughput Screening of Engineered Strains and Enzymes Based on Ultraviolet, Visible, and Fluorescent Spectroscopy

Genetic engineering and directed evolution are effective methods for addressing the low yield and poor industrialization level of microbial target products. The current research focus is on how to efficiently and rapidly screen beneficial mutants from constructed large-scale mutation libraries. Traditional screening methods such as plate screening and well-plate screening are severely limited in their development and application due to their low efficiency and high costs. In the past decade, microfluidic technology has become an important high-throughput screening technology due to its fast speed, low cost, high automation, and high screening throughput, and it has developed rapidly. Droplet-based microfluidic high-throughput screening has been widely used in various fields, such as strain/enzyme activity screening, pathogen detection, single-cell analysis, drug discovery, and chemical synthesis, and has been widely applied in industries such as those involving materials, food, chemicals, textiles, and biomedicine. In particular, in the field of enzyme research, droplet-based microfluidic high-throughput screening has shown excellent performance in discovering enzymes with new functions as well as improved catalytic efficiency or stability, acid-base tolerance, etc. Currently, droplet-based microfluidic high-throughput screening technology has achieved the high-throughput screening of enzymes such as glycosidase, lipase, peroxidase, protease, amylase, oxidase, and transaminase as well as the high-throughput detection of products such as riboflavin, coumarin, 3-dehydroquinate, lactic acid, and ethanol. This article reviews the application of droplet-based microfluidics in high-throughput screening, with a focus on high-throughput screening strategies based on UV, visible, and fluorescence spectroscopy, including labeled optical signal detection screening, as well as label-free electrochemical detection, mass spectrometry, Raman spectroscopy, nuclear magnetic resonance, etc. Furthermore, the research progress and development trends of droplet-based microfluidic technology in enzyme modification and strain screening are also introduced.

Engineering of redox partners and cofactor NADPH supply of CYP68JX for efficient steroid two-step ordered selective hydroxylation activity

CYP68JX, a P450 hydroxylase, derived from Colletotrichum lini ST-1 is capable of biotransforming dehydroepiandrosterone (DHEA) to 3β,7α,15α-trihydroxy-5-androstene-17-one (7α,15α-diOH-DHEA). Redox partners and cofactor supply are important factors affecting the catalytic activity of CYP68JX. In this study, the heterologous expression of CYP68JX in Saccharomyces cerevisiae BY4741 was realized resulting in a 17.1% target product yield. In order to increase the catalytic efficiency of CYP68JX in S. cerevisiae BY4741, a complete cytochrome P450 redox system was constructed. Through the combination of CYP68JX and heterologous CPRs, the yield of the target product 7α,15α-diOH-DHEA in CYP68JX recombinant system was increased to 37.8%. Furthermore, by adding NADPH coenzyme precursor tryptophan of 40 mmol/L and co-substrate fructose of 20 g/L during the conversion process, the catalytic efficiency of CYP68JX was further improved, the target product yield reached 57.9% which was 3.39-fold higher than initial yield. Overall, this study provides a reference for improving the catalytic activity of P450s.

Non-Invasive Detection of Biomolecular Abundance from Fermentative Microorganisms via Raman Spectra Combined with Target Extraction and Multimodel Fitting.

Biomolecular abundance detection of fermentation microorganisms is significant for the accurate regulation of fermentation, which is conducive to reducing fermentation costs and improving the yield of target products. However, the development of an accurate analytical method for the detection of biomolecular abundance still faces important challenges. Herein, we present a non-invasive biomolecular abundance detection method based on Raman spectra combined with target extraction and multimodel fitting. The high gain of the eXtreme Gradient Boosting (XGBoost) algorithm was used to extract the characteristic Raman peaks of metabolically active proteins and nucleic acids within E. coli and yeast. The test accuracy for different culture times and cell cycles of E. coli was 94.4% and 98.2%, respectively. Simultaneously, the Gaussian multi-peak fitting algorithm was exploited to calculate peak intensity from mixed peaks, which can improve the accuracy of biomolecular abundance calculations. The accuracy of Gaussian multi-peak fitting was above 0.9, and the results of the analysis of variance (ANOVA) measurements for the lag phase, log phase, and stationary phase of E. coli growth demonstrated highly significant levels, indicating that the intracellular biomolecular abundance detection was consistent with the classical cell growth law. These results suggest the great potential of the combination of microbial intracellular abundance, Raman spectra analysis, target extraction, and multimodel fitting as a method for microbial fermentation engineering.

<i>N</i>-arylation of 1,2,4- and 1,3,4-oxadiazolones under the conditions of activitated aromatic nucleophilic substitution

The possibilities of N -arylation of 1,2,4-oxadiazol-5(4 Н )-ones and 1,3,4-oxadiazol-2(3 Н )-ones with various electron-deficient chloro- and fluorine-substituted nitroarenes under the conditions of classical activated nucleophilic substitution were studied. A significant difference was shown in the reactivity of 1,2,4- and 1,3,4-oxadiazolones in N -arylation reactions. Methods for the synthesis of N-nitroaryl derivatives have been developed.1,2,4- and 1,3,4-oxadiazolones, providing yields of target products with sufficient purity and good yields at the level of 65-96%.