Degree Of Unsaturation Research Articles

Comparative Analysis of Produced Organic Soap from Garlic Juice-Benni-Seed Stalk Ash Extract and Coconut Oil and Some Selected Commercial Soaps

Comparative Analysis of Organic Soap Produced from Garlic Juice-Benni-Seed Stalk Ash Extract and Coconut Oil and some Selected Commercial Soaps. The method used involved Collection of Benni-seed stalk and preparation of Alkali, Collection and Extraction of Coconut Oil, Collection of Garlic Bulb and Preparation of the Garlic Juice- based Alkaline. The produced soap was characterized based on physical characteristics (Soap Types, Colour, Texture, Aroma and Cleaning efficiency), pH of the soap samples, Foaming Stability, water hardness Test and Wash Fastness Properties Test. The result of the study shows that variation occurred among soap types as a result of addition of colouring matter such as dyes and degree of unsaturation of fatty acids. The pH of all the soaps falls within the range pH of (7-8) improving soaps quality but to regulate the pH level which will not contribute to the harshness of hands and skin. In terms of foaming stability, result obtained from GBC Soap was the best due to its solubility in water. Analysis of Soap hardness in soft water and hard water shows that Bright Soap had the highest value (8.5) in soft water which made it the best among other soap products. Premier Soap had the best ability to maintain the quality of fabric material when washed in water.

Exploring the potential of AI-Chatbots in organic chemistry: An assessment of ChatGPT and Bard

The invention of AI-Chatbot is undeniably one of the most remarkable achievements by humanity, harnessing an unparalleled level of power and potential. In the near future, AI-chatbots are expected to become valuable tools in education, aiding students in their learning journeys. This study aims to explore the performance and accuracy of two chatbots, ChatGPT and Bard in understanding text-based structural notations such as, condensed structures, InChi and SMILES and answering organic chemistry related questions. Their ability to perform tasks such as converting IUPAC names, InChi, and SMILES notations into condensed forms and vice versa, identifying functional groups, generating molecular formulas, and predicting resonance patterns was studied. The ChatGPTs' accuracy percentages for various tasks are as follows: determining degree of unsaturation from molecular formulas (90-80%), InChi (79-64%), and SMILES (86-64%); identifying functional groups from condensed structures (94%) and InChi (65-50%); converting condensed structures to molecular formulas (86-73%), IUPAC (38%), InChi (22-17%), and SMILES (56-44%); converting InChi to IUPAC (65-50%) and condensed structures (28-11%); and converting SMILES to condensed structures (42-37%) and IUPAC (25-20%). In contrast, Bard consistently performed lower in most tasks. Both chatbots had significant limitations, especially with InChi and SMILES notations which have been used successfully in machine learning. GPT-4, the newer version of ChatGPT, was also tested against these tasks, and slight improvements were observed in most areas, particularly in reading SMILES notations. While these advanced AI-chatbots hold promising potential as enduring educational tools in organic chemistry, inspiring reevaluation of teaching strategies, their implementation should be carefully monitored, particularly considering the rapid pace of advancements.

Research of chemical transformations in the technology of hydrogenation of vegetable oils

Chemical transformations in the technology of hydrogenation of vegetable oils have been studied. The equations describing the saturation of fatty acids in hydrogenation technology have been established. The diffusion coefficients of hydrogen and triglycerides in oils and fats have been determined. It has been shown that the observed rate of hydrogenation does not depend on the amount of catalyst and the degree of unsaturation of the fat. The high quality and food safety of catalytically hydrogenated edible fats have the required content and ratio of solid and liquid fractions of fatty acids in fat triglycerides, maintain the quantitative content of biologically important components in the composition of the initial raw material. The selection of the additive and its use in the composition of catalytic systems allows establishing and regulating the hydrogenating properties of hydrogenated edible fats with high indicators of quality and food safety. Methods for optimizing technological regimes made it possible to increase the food safety of margarine products and expand its range. The scientific and experimental results have allowed expanding and supplementing the theoretical provisions on improving the quality and food safety of catalytically hydrogenated edible fats based on cottonseed oil using various types of catalytic systems.

Review of Lipid Biomarkers and Signals of Photooxidative Stress in Plants.

The degree of unsaturation of plant lipids is high, making them sensitive to oxidation. They thus constitute primary targets of reactive oxygen species and oxidative stress. Moreover, the hydroperoxides generated during lipid peroxidation decompose in a variety of secondary products which can propagate oxidative stress or trigger signaling mechanisms. Both primary and secondary products of lipid oxidation are helpful markers of oxidative stress in plants. This chapter describes a number of methods that have been developed to measure those biomarkers and signals, with special emphasis on the monitoring of photooxidative stress. Depending on their characteristics, those lipid markers provide information not only on the oxidation status of plant tissues but also on the origin of lipid peroxidation, the localization of the damage, or the type of reactive oxygen species involved.

A cationic lipid with advanced membrane fusion performance for pDNA and mRNA delivery.

The success of mRNA vaccines for COVID-19 prevention raised global awareness of the importance of nucleic acid drugs. The approved systems for nucleic acid delivery were mainly formulations of different lipids, yielding lipid nanoparticles (LNPs) with complex internal structures. Due to the multiple components, the relationship between the structure of each component and the overall biological activity of LNPs is hard to study. However, ionizable lipids have been extensively explored. In contrast to former studies on the optimization of hydrophilic parts in single-component self-assemblies, we report in this study on structural alterations of the hydrophobic segment. We synthesize a library of amphiphilic cationic lipids by varying the lengths (C = 8-18), numbers (N = 2, 4), and unsaturation degrees (Ω = 0, 1) of hydrophobic tails. Notably, all self-assemblies with nucleic acid have significant differences in particle size, stability in serum, membrane fusion, and fluidity. Moreover, the novel mRNA/pDNA formulations are characterized by overall low cytotoxicity, efficient compaction, protection, and release of nucleic acids. We find that the length of hydrophobic tails dominates the formation and stability of the assembly. And at a certain length, the unsaturated hydrophobic tails enhance the membrane fusion and fluidity of assemblies and thus significantly affect the transgene expression, followed by the number of hydrophobic tails.

Direct dehydrogenation of propane over Co@silicalite-1 zeolite: Steaming-induced restructuring of Co2+ active sites

The chemical state of the Co-relevant active site determines the catalytic performance of the Co-containing zeolite catalysts in non-oxidative propane dehydrogenation (PDH) reaction. Herein, we demonstrate that the moderate steaming pre-treatment is an available strategy to enhance catalytic activity of silicalite-1 zeolite-supported Co catalyst through tuning the Co state. The steaming-treated Co@S-1-steam catalyst exhibits sevenfold increased specific reaction rate (0.44 s−1) than the untreated Co@S-1 catalyst and maintains 95 % propylene selectivity in the PDH reaction at 590 °C. By comprehensive characterizations on the structural properties of the catalysts, multiple roles of steaming treatment are discovered. Steaming treatment can induce the reductive restructuring of the Co catalytic sites in zeolite micropores to form tetrahedral Co2+ species with enhanced dispersion and unsaturation degree, and significantly accelerate the selective activation of propane CH bonds. Furthermore, it also reduces the surface acidity and consequently promotes the desorption of propylene intermediates for enhancing the catalytic reaction rate and anti-coke stability.

Molecular-level evidence of early lipid transformations throughout oceanic depths

Our understanding of lipid biogeochemistry of the ocean’s interior is still in its infancy. Here we focus on early lipid transformation and the formation of lipid degradation products in the NE Atlantic Ocean (49.0°N, 16.5°W). We employed high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), a method that allows observation and elemental composition assignment of thousands of lipids in a single sample. Using these data, we infer molecular-level changes that occur during lipid transformation in the oceanic water column to shed new light on early lipid transformation processes and the formation of lipid decomposition intermediates, here termed CHO compounds (i.e., lipid-derived species that contain carbon, hydrogen and oxygen in their molecular formula). We considered the distribution of molecular rings and/or double bonds (DBE), H/C and O/C ratios, molecular diversity based on the number of mass spectral signals for monoisotopic species, and carbon number in CHO molecules. Data are elaborated for the four ocean zones, the epipelagic, mesopelagic, bathypelagic and abyssal. The highest molecular diversity characterizes CHO compounds associated with the epipelagic zone, which is explained by numerous and diverse planktonic communities inhabiting the epipelagic and by the effects of both biotic and abiotic processes on lipid transformation. Lipid transformations include crosslinking (condensation), partial degradation or fragmentation, double bond reduction, oxidation, hydrogenation, dehydrogenation and cyclization. Crosslinking likely results in a unimodal distribution of carbon number of CHO compounds, in contrast to cell lipids (referred to as Reported lipids based on the Lipid Maps Database), which have a bimodal distribution of carbon number. CHO compounds that appear to be formed by fragmentation (decrease of the number of C atoms) and ring/double bond reduction were more stable to further transformation and remained longer in the water column, i.e., these compounds were transferred deeper into the water column. Low unsaturation and fast transport to depth promotes CHO compound preservation in the water column. Dehydrogenation leads to increased unsaturation (average DBE up to 21.3), condensation, and cyclization, resulting in high molecular weight compounds with a high degree of unsaturation. Our data demonstrate that lipids with cyclic structures are more refractory than those with acyclic structures. The formation of aromatic structures is not a significant process during early lipid transformation in the oceanic water column.

The light absorbing and molecule characteristic of PM2.5 brown carbon observed in urban Shanghai

Both brown carbon (BrC) and the non-absorbing components coated on black carbon (BC) aerosols can enhance the light absorption of BC aerosols. BrC is a complicated mixture of organic compounds and not well characterized, which hinders exploring the links between BrC and optical properties. We conducted an in-depth field study on optical properties of ambient aerosols at a monitoring site in Shanghai, China via real-time monitoring and offline analysis. Results showed that BrC caused light absorption coefficients were 3.3 ± 3.3 Mm−1, 2.2 ± 5.0 Mm−1, 1.2 ± 1.2 Mm−1 at λ = 370, 470 and 520 nm, respectively, accounting for 11%, 10%, 6% of the total aerosol absorption for the corresponding wavelengths. A larger proportion of long-chain aliphatic organosulfates (OSs, CnH2n+2O4S, (CH2)nO5S, (CH2)nO6S) with double bond equivalent (DBE) values of 0 or 1 accounted for 5–20% of the light absorption (λ = 365 nm) for soluble brown carbon (BrC), which were dominating for the days with less N-containing aromatic compounds appearing. Furthermore, the structure of CnH2n+2O4S, (CH2)nO5S, (CH2)nO6S were explored using target MS/MS of HPLC-Q-ToF-MS: (CH2)nO5S series, the most abundant family of OSs, were constructed by functionalizing a saturated hydrocarbon with one sulfate and one carbonyl group. CnH2n+2O4S series were oxidized with only one sulfate group in the aliphatic chain R. (CH2)nO6S series were proposed as aliphatic OSs with one ester group. We speculated aliphatic OSs were formed via acid catalyzed perhydrolysis of hydroperoxides derived from long-chain alkanes releasing from diesel fueled vehicles, followed by the reaction with sulfate anion radicals. Therefore, relevant technologies should be further explored to reduce the impacts from vehicle emissions.

Theoretical Study on Abstraction and Addition Reaction Kinetics for a Medium-Size Unsaturated Methyl Ester: Methyl-3-hexenoate + H/OH Radicals.

Combustion chemistry of methyl esters with long alkyl chains and different degrees of unsaturation has been of particular interest for biodiesel combustion. Methyl-3-hexenoate (mhx3d) with a medium-size unsaturated aliphatic chain is regarded as a valuable surrogate of biodiesel components. Here, the abstraction and addition reaction kinetics of mhx3d + H/OH radicals are comprehensively investigated. An accurate and efficient exchange-correlation density functional M06-2X/ma-TZVP is validated by the DLPNO-CCSD(T)/CBS(T-Q) benchmark calculations and is used for the multistructural search, geometry optimization, potential energy profiles, and direct dynamic calculations. The multistructural torsional (MS-T) anharmonicity, variational effects, and tunneling effects including one-dimensional Winger tunneling, multidimensional zero-curvature tunneling (ZCT), and small-curvature tunneling (SCT) are also evaluated in rate coefficient calculations. The existence of reactant complexes of the abstraction and addition reactions is neglected for mhx3d + H due to weak van der Waals interaction but is considered for mhx3d + OH. Therefore, a pre-equilibrium model is employed to obtain the rate coefficients for mhx3d + OH. The calculation results show that the MS-T factor ranges from 0.29 to 11.41, the tunneling transmission coefficient calculated by SCT is in the range of 1.0-4.0, and the recrossing transmission coefficient is between 0.65 and 1.0. Moreover, the two OH-addition reactions exhibit negative temperature coefficient behavior. The branching ratios show that the H/OH-addition reactions are dominant at lower temperature, especially for mhx3d + H. Rate coefficients of the title reactions are fitted in terms of a modified three-parameter Arrhenius expression.

Detection and Semi-quantification of Lipids on High-Performance Thin-Layer Chromatography Plate using Ceric Ammonium Molybdate Staining.

It is desirable to quickly check the composition of lipids in small size samples, but achieving this is challenging using the existing staining methods. Herein, we developed a highly sensitive and semi-quantitative method for analysis of lipid samples with ceric ammonium molybdate (CAM) staining. The CAM detection method was systematically evaluated with a wide range of lipid classes including phospholipids, sphingolipids, glycerolipids, fatty acids (FA) and sterols, demonstrating high sensitivity, stability, and overall efficiency. Additionally, CAM staining provides a clean yellow background in high performance thin-layer chromatography (HPTLC) which facilitates quantification of lipids using image processing software. Lipids can be stained with CAM reagent regardless of their head group types, position of the carbon-carbon double bonds, geometric isomerism and the variation in the length of FA chain, but staining is mostly affected by the degree of unsaturation of the FA backbone. The mechanism of the CAM staining of lipids was proposed on principles of the reduction-oxidation reaction, in which Mo(VI) oxidizes the unsaturated lipids into carbonyl compounds on the HPTLC plate upon heating, while itself being reduced to Mo(IV). This method was applied for the separation, identification, and quantification of lipid extracts from porcine brain.

Chemometric analysis applied to 1 H NMR and FTIR data for a quality parameter distinction of red fruit (Pandanus conoideus, lam.) oil products.

Red fruit oil (RFO) is a natural product extracted from Pandanus conoideus Lam. fruit, a native plant from Papua, Indonesia. Recent studies indicate that RFO is popularly consumed as herbal medicine. Therefore, the quality of RFO must be assured. This study aimed to develop a chemometric analysis applied to 1 H nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) data for important quality parameter distinction of red fruit oil (RFO), especially regarding the degree of unsaturation and the amount of free fatty acids (FFA). Forty samples consisting of one crude RFO, thirty-three commercial RFOs, and three oils as blends, including olive oil, virgin coconut oil, and black seed oil, were analysed by 1 H NMR and FTIR spectroscopy. After appropriate preprocessing of the spectra, principal component analysis (PCA) and partial least squares regression (PLSR) were used for model development. The essential signals for modelling the degree of unsaturation are the signal at δ = 5.37-5.27 ppm (1 H NMR) and the band at 3000-3020 cm-1 (FTIR). The FFA profile represents the signal at δ = 2.37-2.20 ppm (1 H NMR) and the band at 1680-1780 cm-1 (FTIR). PCA allows the visualisation grouping on both methods with > 98% total principal component (PC) for the degree of unsaturation and > 88% total PC for FFA values. In addition, the PLSR model provides an acceptable coefficient of determination (R2 ) and errors in calibration, prediction, and cross-validation. Chemometric analysis applied to 1 H NMR and FTIR spectra of RFO successfully grouped and predicted product quality based on the degree of unsaturation and FFA value categories.

Stable isotope labeling for detection of ozonation byproducts in effluent organic matter with FT-ICR-MS

Despite effluent organic matter (EfOM) being a major consumer of ozone during wastewater treatment, little is known about ozonation byproducts (OBPs) produced from EfOM. To unambiguously identify OBPs, heavy ozone was used to ozonate EfOM, resulting in 18O labeled and unlabeled OBPs. Labeled OBPs mostly represent a single 18O transfer and were classified as either direct or indirect OBPs based on the 18O/16O intensity ratios of the isotopologues. Of the 929 labeled OBPs, 84 were unequivocally classified as direct OBPs. The remainder suggest a major contribution by indirect, hydroxyl radical induced formation of OBPs in EfOM. Overall, labelled OBPs possess a low degree of unsaturation and contributed most to OBP peak intensity – marking them as potential end products. A few direct and indirect OBPs with high peak intensity containing 18O and heteroatoms (N, S) were fragmented with CID FT-ICR-MS/MS and screened for indicative neutral losses carrying heavy oxygen. The neutral loss screening was used to detect the 18O location on the OBP and indicate the original functional group in EfOM based on known reaction mechanisms. We identified sulfoxide and sulfonic acid functional groups in selected OBPs – implying the presence of reduced sulfur in EfOM molecules – while no evidence for nitrogen containing functional groups reacting with ozone was found.

OGC O09 The clinical utilisation of tissue imaging Mass Spectrometry as a diagnostic model for Oesophageal Adenocarcinoma

Abstract Background The prevalence of Oesophageal adenocarcinoma (OA) in the United Kingdom has steadily risen since the 1970's. The majority of patients present with advanced disease. Early diagnosis utilising point of care testing may enable an increase in the number of patients managed on a potentially curative pathway. Tissue Imaging Mass Spectrometry by Desorption Electrospray (DESI-MS) is one such tool to differentiate the abundance of lipids in OA. This work presents the novel use of Mass Spectrometry (MS) imaging to identify variations in lipid abundance between OA and normal oesophagus (NO). Methods Tissue was sampled from specimens dissected immediately post-resection from the tumour and at 5-centimetre intervals in the proximal NO. Forty-one unique patient OA and NO tissue samples were analysed in triplicate by DESI-MS tissue imaging to differentiate Glycerophospholipids. A total of 246 DESI-MS images were correlated with paired formalin fixed Haematoxylin and Eosin stained tissue slides, the current gold standard cancer diagnostic test. Principle component analysis utilising a supervised model classified tissue types with a significance of p=0.01. Receiver operator curves (ROC) were used to determine the diagnostic sensitivity and specificity of DESI-MS for the identification of adenocarcinoma. Results Tissue analysis confirmed unsaturated Phosphatidylglycerols and Phosphatidic acids were significantly more abundant in OA compared to NO (p<0.001). Tissue analysis by a Partial Least Square (PLS) supervised linear regression model classified cancer and non-cancer tissue with a confusion matrix classification of 93.3% and 70.8% for OA and NO (Figure 1a-c). A diagnostic sensitivity of 85% and specificity of 88% was determined by ROC curve. The abundance of Phosphatidylglycerol and Phosphatidylserine decreased proportionally in analysed tissue sections at 5cm and 10cm from the primary tumour, as did the degree of lipid unsaturation. Conclusions This work presents a novel tissue imaging MS model to differentiate lipid abundance in OA. An abundance ratio of 1.17:1 (OA:NO) of unsaturated Phosphatidylglycerol was diagnostic of cancer by DESI-MS with a high sensitivity and specificity. This MS tissue analysis model has the potential to enable accurate point of care diagnostics for OA. In addition, we suggest oesophageal cancer induced perturbation of Glycerophospholipid metabolism may be a potential target for future chemotherapeutics.

Understanding the membrane fouling control process at molecular level in the heated persulfate activation- membrane distillation hybrid system

Sulfate radical (SO4●−) based advanced oxidation is considered as a promising pretreatment strategy to degrade organic pollutants and thereby mitigate the membrane fouling in the membrane process. In this study, heat-activated persulfate (PS) activation was integrated with the membrane distillation (MD) process for the alleviation of membrane fouling in treatment of wastewater treatment plant (WWTP) secondary effluent and surface water. In-depth understanding of the molecular fate during membrane fouling control process was performed by using a non-targeted screening method of two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC−TOF−MS) coupling with multiple characterizations. It was found that the heat-activated PS activation pretreatment could effectively degrade the dissolved organic matter (DOM) and change its molecular conformation, wherein the relative abundance of oxygen-containing substances was remarkably increased through oxygenation reactions. Moreover, the refractory organics with higher molecular weight (MW) and unsaturation degree were more inclined to be destroyed, following by partial mineralization during pretreatment process. It was also identified that oxygen-deficient compounds and the molecular formulas featuring higher double bond equivalent (DBE) values and lower MW tended to be deposited on the membrane surface to cause the membrane fouling. In particular, the aliphatic substances were the predominant components irrespective of membrane foulant samples from secondary effluent or surface water. Meanwhile, the complexation between organic compounds and high valence cations as well as the precipitation of inorganics were restrained owing to the reduction of DOM concentration and the transformation of molecular structure, consequently leading to reduced membrane fouling. This study is believed to further provide new insight into the membrane fouling control mechanism at molecular level.

Characterization of responsive zein-based oleogels with tunable properties fabricated from emulsion-templated approach

Recently, studies on the oleogelation, a promising strategy to construct oil, have attracted an increasing attention. In our study, emulsion-templated approach using zein as oleogelator was adopted to obtain edible oleogels by using oils with different degree of unsaturation. The formation, structure information, as well as linear and nonlinear rheological behaviors of oleogels were explored. Results showed that the storage modulus and apparent viscosity of emulsions were positively correlated to the oil polarity. All dried products showed a single broad endothermic peak, similar thermal decomposition pattern, and X-ray diffraction spectra peaks. The oleogelator-oleogelator (hydrogen bond and hydrophobic), oleogelator-oil (hydrophobic), and oil-oil (van der Waals) interactions might contribute to the network formation. Small amplitude oscillatory shear demonstrated oleogels featured high elastic and good thixotropic recovery properties. Large amplitude oscillatory shear showed corn oil-oleogel exhibited smaller nonlinearity and network structure deformation. Moreover, quercetin-loaded oleogels exhibited thermal reversibility and malleability regardless of oil phases. Therefore, oleogels with different oil phases might have great potent applications in 3D-printed food and active ingredients delivery. The study might provide significance for the application of protein-structured oil as a solid fat replacer. • Zein self-assembled to form emulsions and oleogels with varied unsaturation fatty acid. • The Pickering emulsion template was fabricated via one-step ultrasonic treatment. • β-sheet structure contributed to assemble a rigid gel-like protein interfacial film. • Quercetin contributed to slow down the oleogels deformation. • Quercetin-loaded oleogels had thermo-reversible and thixotropic recovery properties.

Particulate Organic Matter Mobilization and Transformation Along a Himalayan River Revealed by ESI‐FT‐ICR‐MS

AbstractTracing pathways and transformations of particulate organic carbon from landscape sources to oceanic sinks is commonly done using the isotopic composition or biomarker content of particulate organic matter (POM). However, similarity of source characteristics and complex mixing in rivers often preclude a robust deconvolution of individual contributions. Moreover, these approaches are limited in detecting organic matter transformations. This impedes understanding of carbon cycling. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT‐ICR‐MS) can simultaneously identify many molecular formulas from mixtures of organic matter, and provide direct information on its compositional variability. Here, we investigate how FT‐ICR‐MS can give insight into POM dynamics on a landscape scale, focusing on the trans‐Himalayan Kali Gandaki River, Nepal. Using molecular information, we identify source tracers in the solvent extractable lipid fraction of riverine POM, finding up to 102 indicative molecular formulas for individual sources. Further, we assess molecular transformations of the lipid fraction of POM during its transfer from litter into topsoil, and onwards into the river. A large number of shared mass formulas and a well‐preserved isoprenoidal patterns suggest efficient incorporation of litter into topsoil. In contrast, we observe a selective loss of mass formulas and a preferential export of formulas with low double bond equivalents and a low nominal oxidation state of carbon after organic matter entrainment in the river. Our results demonstrate the potential of FT‐ICR‐MS for source‐to‐sink studies, allowing detailed organic matter source characterization and discrimination, and tracking of molecular transformations along organic matter pathways spanning different spatial and temporal scales.

Lipidomic analysis of moss species Bryum pseudotriquetrum and Physcomitrium patens under cold stress.

Bryophytes, which lack lignin for protection, support themselves in harsh environments by producing various chemicals. In response to cold stress, lipids play a crucial role in cell adaptation and energy storage. Specifically, bryophytes survive at low temperatures by producing very long-chain polyunsaturated fatty acids (vl-PUFAs). The in-depth understanding of the lipid response to cold stress of bryophytes was studied by performing lipid profiling using ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS). Two moss species (Bryum pseudotriquetrum and Physcomitrium patens) cultivated at 23°C and at 10°C were included in this study. Relative quantitative lipid concentrations were compared and the potential lipid biomarkers were identified by multivariate statistical analysis in each species. In B. pseudotriquetrum, it was observed that the phospholipids and glycolipids increased under cold stress, while storage lipids decreased. The accumulation of the lipids with high unsaturation degrees mostly appears in phospholipids and glycolipids for both mosses. The results also indicate that two unusual lipid classes in plants, sulfonolipids and phosphatidylmethanol are biosynthesized by the bryophytes. This has not been seen previously and show that bryophytes have a very diverse chemistry and substantially different from other plant groups.

Molecular characterization of humic-like substances (HULIS) in atmospheric particles (PM2.5) in offshore Eastern China Sea (OECS) using solid-phase extraction coupled with ESI FT-ICR MS

Humic-like substances (HULIS) are organic macromolecular compounds (water-soluble brown carbon) that have an important effect on climate change due to their strong light absorption. However, the molecular composition of HULIS in atmospheric particles in the offshore Eastern China Sea (OECS) has scarcely been investigated. In this study, solid-phase extraction (SPE) was performed to collect HULIS from water extracts. The molecular compositions of samples were characterized by negative-ion electrospray ionization (ESI) Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). A total of 1197–1828 molecular formulas of HULIS were identified in collected samples, and three of them with higher intensities near Shanghai city, Zhejiang province, and Fujian province were discussed in detail. The identified molecular formulas were classified into four major subgroups, including CHO, CHNO, CHOS, and CHNOS compounds. S-containing formulas (CHOS and CHNOS) represented the dominant components (21.0–76.7% relative abundance), followed by CHO (16.5–64.3%), while CHNO compounds constituted 6.1–18.1% of the identified formulas. High fractions of CHO formulas were found in the list of α-pinene ozonolysis yields and S-containing formulas with olefinic structures were abundant in atmospheric particles, suggesting enhanced SOA formation. The samples had a relative abundance-weighted average O/C of 0.25–0.67 and a double bond equivalent of 3.49–4.96. Most identified formulas (>89%) were assigned to aliphatic and olefinic species. The CHNO and S-containing formulas identified in the samples were primarily contributed by –ONO2 functional groups and organosulfates. Biogenic volatile organic compounds (α-pinene or monoterpene) were the dominant precursors of HULIS in the samples. Lignin-like species (41–46%) and protein/amino sugars (28–30%) were the major species among substance classes. The results provide an improved understanding of the molecular composition of HULIS in the Eastern China Sea.

Fatty Acid Composition of Comamonas testosteroni under Hexachlorobenzene Loading Conditions

Changes in the lipid composition in bacterial membranes are considered to be the most important adaptation mechanisms to adverse chemical factors. The aim of the study was to compare the hexachlorobenzene effects on the fatty acid composition of total lipids Comamonas testosteroni. Methods. The study was performed with C. testosteroni UCM B-400 and B-401, B-213 strains. Bacteria were grown in the Luria-Bertrani (LB) liquid medium containing 10 and 20 mg/L of hexachlorobenzene (HCB). After cultivation, the biomass was separated by centrifugation and the fatty acid composition of total lipids was determined through analyzing its methyl esters. To assess the cell membrane properties, such parameters as the lipid unsaturation index, the average carbon chain length of fatty acids, and the membrane viscosity index were determined. Results. In the fatty acids spectrum of C. testosteroni B-400 after cultivation in a medium containing 20 mg/L of HCB, the contents of unsaturated hexadecenoic (C16:1) and octadecenoic (C18:1) acids were lower by 10.6 and 5.5%, respectively, and that of saturated hexadecanoic (C16:0) acid was higher by 8.4%, compared to the control. The fatty acid composition of C. testosteroni B-401 was more stable compared to strain B-400. Collection strain C. testosteroni B-213 compared to strains isolated from soil with high HCB load, in the presence of 10 and 20 mg/L of HCB had the highest relative content of saturated hexadecanoic acid (C16:0) up to 38.33—40.7%. Unsaturated octadecenoic acid decreased at the doses 10 and 20 mg/L to 1.5—2% compared to the control. In all strains under the HCB impact, there was an increase in the relative content of C17-cyclopropanoic acid compared to control variants. Conclusions. C. testosteroni UCM B-400, B-401, and B-213 bacteria under cultivation conditions in HCB-containing medium, decreasing the degree of lipid unsaturation and increasing the relative content of C17-cyclopropanoic acid can be considered as the main mechanisms regulating the cytoplasmic membrane fluidity; the displaying of these protective reactions had a strain trait and did not depend on the adaptation in natural isolating places.

Maximizing Nitrogen Removal and Lipid Production by Microalgae under Mixotrophic Growth Using Response Surface Methodology: Towards Enhanced Biodiesel Production

The present study aimed to optimize synthetic wastewater composition as a mixotrophic medium for enhanced growth and lipid accumulation coupled with high nitrogen removal by the green microalga Chlorella sp. Individual effects of the three main independent variables (nitrate concentration, seawater ratio, and glycerol supplementation) were tested initially, then response surface methodology (RSM) was subsequently performed to explore the optimum combined conditions. The highest lipid productivity of 37.60 mg/L day was recorded at 25% seawater. Glycerol supplementation enhanced both lipid content and biomass production, which resulted in the highest recorded lipid productivity of 42.61 mg/L day at 4 g/L glycerol. Central composite design followed by numerical optimization was further applied which suggested NaNO3 concentration at 101.5 mg/L, seawater ration of 23.8%, and glycerol supplementation of 0.25 g/L as the optimum conditions for dual maximum lipid productivity and nitrogen removal of 46.9 mg/L day and 98.0%, respectively. Under the optimized conditions, dry weight and lipid content increased by 31.9% and 20.3%, respectively, over the control, which resulted in increase in lipid productivity by 71.5%. In addition, optimization process resulted in pronounced changes in fatty acid proportions where saturated fatty acids increased by 7.4% in the optimized culture with simultaneous reduction of polyunsaturated fatty acids. The estimated biodiesel characteristics calculated from the fatty acid methyl ester (FAMEs) profile showed agreement with the international standards, while optimized cultures showed an 8.5% lower degree of unsaturation, which resulted in higher cetane numbers and lower iodine values. This study provides economical approach for optimization and efficient nutrient recycling through cultivation of Chlorella sp. for further enhanced biodiesel production.