Succinic Acid Research Articles

A Large-Scale Genome-Wide Gene-Sleep Interaction Study in 732,564 Participants Identifies Lipid Loci Explaining Sleep-Associated Lipid Disturbances.

We performed large-scale genome-wide gene-sleep interaction analyses of lipid levels to identify novel genetic variants underpinning the biomolecular pathways of sleep-associated lipid disturbances and to suggest possible druggable targets. We collected data from 55 cohorts with a combined sample size of 732,564 participants (87% European ancestry) with data on lipid traits (high-density lipoprotein [HDL-c] and low-density lipoprotein [LDL-c] cholesterol and triglycerides [TG]). Short (STST) and long (LTST) total sleep time were defined by the extreme 20% of the age- and sex-standardized values within each cohort. Based on cohort-level summary statistics data, we performed meta-analyses for the one-degree of freedom tests of interaction and two-degree of freedom joint tests of the main and interaction effect. In the cross-population meta-analyses, the one-degree of freedom variant-sleep interaction test identified 10 loci (P int <5.0e-9) not previously observed for lipids. Of interest, the ASPH locus (TG, LTST) is a target for aspartic and succinic acid metabolism previously shown to improve sleep and cardiovascular risk. The two-degree of freedom analyses identified an additional 7 loci that showed evidence for variant-sleep interaction (P joint <5.0e-9 in combination with P int <6.6e-6). Of these, the SLC8A1 locus (TG, STST) has been considered a potential treatment target for reduction of ischemic damage after acute myocardial infarction. Collectively, the 17 (9 with STST; 8 with LTST) loci identified in this large-scale initiative provides evidence into the biomolecular mechanisms underpinning sleep-duration-associated changes in lipid levels. The identified druggable targets may contribute to the development of novel therapies for dyslipidemia in people with sleep disturbances.

Oxidative heterocoupling of lithium 2-methylpropanoate α-carbanion and secondary α-carbanions of lithium acylates

When the α-carbanion of 2-methylpropanoate (A) reacts with the α-carbanions of lithium butanoate, pentanoate, hexanoate, heptanoate and phenylacetate (B) in the presence of 1,2-dibromoethane, a mixture of oxidative homocoupling (A-A, B-B) products [2,2,3,3-tetramethyl- and 2,3-diethyl- (or 2,3-dipropyl-, 2,3-dibutyl-, 2,3-dipentyl-, 2,3-diphenyl)succinic acids] and heterocouplings (A-B) products [2,2-dimethyl-3-ethyl- (or 2,2-dimethyl-3-propyl-, 2,2-dimethyl-3-butyl-, 2,2-dimethyl-3 -pentyl-, 2,2-dimethyl-3-phenyl)succinic acids] is formed with a total yield of 84–98%. The effect of the nature of the oxidizing reagent (1,2-dibromoethane and other reagents) and the molar ratio of coupling α-carbanions of lithium acylates on the selectivity of the formation of homo- and heterocoupling products was studied.

Potassium indole-3-butyric acid affects rice's adaptability to salt stress by regulating carbon metabolism, transcription factor genes expression, and biosynthesis of secondary metabolites.

Soil salinity pollution is increasing worldwide, seriously affecting plant growth and crop production. Existing reports on how potassium indole-3-butyric acid (IBAK) regulates rice salt stress adaptation by affecting rice carbon metabolism, transcription factor (TF) genes expression, and biosynthesis of secondary metabolites still have limitations. In this study, an IBAK solution at 40 mg L-1 was sprayed on rice leaves at the seedling stage. The results showed that the IBAK application could promote shoot and root growth, decrease sucrose and fructose content, increase starch content, and enhance acid invertase (AI) and neutral invertase (NI) activity under salt stress, indicating altered carbon allocation. Furthermore, the expression of TF genes belonging to the ethylene responsive factor (ERF), WRKY, and basic helix-loop-helix (bHLH) families was influenced by IBAK. Many key genes (OsSSIIc, OsSHM1, and OsPPDKB) and metabolites (2-oxoglutaric acid, fumaric acid, and succinic acid) were upregulated in the carbon metabolism pathway. In addition, this study highlighted the role of IBAK in regulating the biosynthesis of secondary metabolites pathway, potentially contributing to rice stress adaptability. The results of this study can provide new sustainable development solutions for agricultural production.

Biodegradation of polybutylene succinate by an extracellular esterase from Pseudomonas mendocina

An extracellular esterase (HP) with polybutylene succinate (PBS)-degrading ability was identified from Pseudomonas mendocina SA-1503. The HP also had the ability to degrade poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and polycaprolactone. This HP had optimal activity at pH 9.0 and 40 °C and remained stable at pH 8.0–9.0 and temperatures of 30–40 °C. Mn2+ promoted the enzyme activity. HP could hydrolyze all p-NP fatty acid ester substrates containing even numbers of carbon atoms from C2 to C18 and had the highest catalytic activity for the p-NP C6 substrate. After 60 h of HP-catalyzed degradation, PBS films experienced a weight loss of more than 60%. Butanedioic acid, 1,4-butanediol, and a series of oligomers were detected in the degradation products of PBS by HP. Further structural analysis of HP revealed that it could be classified as a microbial esterase of α/β hydrolase superfamily and contained a conserved catalytic triad structure (Ser-148, Asp-198, and His-228) with a relatively exposed active site.

Hyaluronic Acid Influences Amino Acid Metabolism via Differential L‐Type Amino Acid Transporter 1 Expression in the U87‐Malignant Glioma Cell Line

The glioblastoma (GBM) tumor microenvironment is heterogeneous, complex, and being increasingly understood as a significant contributor to tumor progression. In brain tumors, the extracellular matrix contains a large concentration of hyaluronic acid (HA) that makes it important to study its role in cancer progression. In particular, abnormal accumulation of HA is observed in gliomas and is often associated with poor prognosis. In addition, HA is a polymer and its molecular weight (MW) distribution may influence tumor cell activity. Herein, the influence of the MW of HA on tumor cell metabolism is evaluated. A 2D cell culture approach is used to expose the U87‐MG (medium glucose [MG]) cell line to different HA MWs (10, 60, and 500 kDa) and glucose concentrations (0, 5.5, and 25 mm). Notably, it is found that HA influences GBM amino acid metabolism via reduction in LAT1 transporter protein expression. Also an influence on mitochondrial respiration levels and a difference in the accumulation of some key products of cell metabolic activity (lactic acid, glutamic acid, and succinic acid) are reported. Overall, in these results, it is indicated that HA MW can influence GBM metabolic state, with implications for cell invasion and tumor progression.

Multi-Omics Integrative Analyses Identified Two Endotypes of Hip Osteoarthritis.

(1) Background: Osteoarthritis (OA) is a heterogeneous disorder, and subgroup classification of OA remains elusive. The aim of our study was to identify endotypes of hip OA and investigate the altered pathways in the different endotypes. (2) Methods: Metabolomic profiling and genome-wide genotyping were performed on fasting blood. Transcriptomic profiling was performed on RNA extracted from cartilage samples. Machine learning methods were used to identify endotypes of hip OA. Pathway analysis was used to identify the altered pathways between hip endotypes and controls. GWAS was performed on each of the identified metabolites. Transcriptomic data was used to examine the expression levels of identified genes in cartilage. (3) Results: 180 hip OA patients and 120 OA-free controls were classified into three clusters based on metabolomic data. The combination of arginine, ornithine, and the average value of 7 lysophosphatidylcholines had an area under the curve (AUC) of 0.97 (95% CI: 0.96-0.99) to discriminate hip OA from controls, and the combination of γ-aminobutyric acid, spermine, aconitic acid, and succinic acid had an AUC of 0.96 (95% CI: 0.94-0.99) to distinguish two hip OA endotypes. GWAS identified 236 SNPs to be associated with identified metabolites at GWAS significance level. Pro-inflammatory cytokine levels were significantly different between two endotypes (all p < 0.05). (4) Conclusions: Hip OA could be classified into two distinct molecular endotypes. The primary differences between the two endotypes involve changes in pro-inflammatory factors and energy metabolism.

Effect of exogenous free Nε-(carboxymethyl)lysine on diabetes-associated cognitive dysfunction: neuroinflammation, and metabolic disorders

Diabetes-associated cognitive dysfunction has already been attracted considerable attention. Advanced glycation end products (AGEs) from daily diets are thought to be a vital contributor to the development of this diseases. However, the effect of one of the best-characterized exogenous AGEs Nε-(carboxymethyl)lysine (CML) on cognitive function is not fully reported. In the present study, diabetical Goto-Kakizaki (GK) rats were treated with free CML for 8-weeks. It was found that oral consumption of exogenous CML significantly aggravated diabetes-associated cognitive dysfunction in behavioral test. In details, exogenous CML increased levels of oxidative stress, promoted the activation of glial cells in the brain, up-regulated the release of inflammatory cytokines interleukin-6, inhibited the protein expression of the brain-derived neurotrophic factor and thus led to neuroinflammation. Furthermore, exogenous CML promoted the amyloidogenesis in the brain of GK rats, and inhibited the expression of GLUT4. Additionally, several tricarboxylic acid cycle and glutamate-glutamine/γ-aminobutyric acid cycle intermediates including pyruvate, succinic acid, glutamine, glutamate were significantly changed in brain of GK rats treated with exogenous free CML. In conclusion, exogenous free CML is a potentially noxious compounds led to aggravated diabetes-associated cognitive dysfunction which could be possibly explained by its effects on neuroinflammation, energy and neurotransmitter amino acid homeostasis.

Microbiota-derived succinic acid mediates attenuating effect of dietary tomato juice supplementation on steatohepatitis through enhancing intestinal barrier

The hepatoprotective potential of tomato juice (TJ) has been reported in chronic liver models, and its potential prebiotic properties may be key to its preventative effects. However, the mechanistic role of the gut microbiota and its derived metabolites in ameliorating nonalcoholic steatohepatitis (NASH) via TJ remains unclear. In this study, we explored how TJ regulates gut microbiota and succinic acid (SA) to restore intestinal barrier function and thus suppress NASH progression. TJ supplementation effectively reduced serum lipid concentrations, alleviated endotoxin levels, and suppressed activation of the endotoxin-TLR4-NF-κB pathway in methionine-choline-deficient (MCD) diet-induced NASH mice. TJ restored the MCD diet-induced gut microbiota dysbiosis, increased the abundance of short-chain fatty acid and SA-producing bacteria (Bifidobacterium, Ileibacterium, Odoribacter, and Parasutterella) and enhanced the expression of intestinal barrier-associated proteins (E-cadherin, Claudin-1, MUC-2, and ZO-1). The hepatoprotective and enteroprotective effects of TJ were abolished in an antibiotic-treated mouse model, underscoring the pivotal role of the gut microbiota in the beneficial effects of TJ on NASH. Fecal metabolomics demonstrated that TJ significantly upregulated the tricarboxylic acid cycle, pyruvate metabolism, and butanoate metabolism pathways, increasing levels of butyric acid (BA) and SA—metabolites associated with reduced hepatic steatosis and intestinal damage. We further found that the physiological concentration of SA, rather than BA, could reduce pro-inflammatory cytokines (TNF-α and IL-6) levels and enhance mucin proteins and tight junction markers in the LPS-induced colon cell line LS174T. This study uncovers new mechanisms by which TJ prevents NASH, highlighting the potential of TJ and SA as effective dietary supplements for patients with chronic liver diseases.

Pickering emulsion of pepper essential oil stabilized by Octenyl succinic acid starch: Characterization, in vitro release and anticancer activity.

Under high humidity and high temperature conditions, the quality of pepper essential oil easily deteriorates, and the oxidation of oil restricts its application, especially for the insolubility in water. This study investigated pepper essential oil encapsulated in Pickering emulsion with octenyl succinic acid starch, which was effectively able to reduce 100 times of the release rate. The smooth surface and complete particles of the emulsion were observed and no new chemical bonds were formed. The minimum particle sizes were 2.05µm and 1.89µm, when the Pickering emulsion was set to different storage conditions at pH 5 and 0.1M NaCl, respectively. During gastrointestinal digestion, the release of essential oils was effectively delayed in the Pickering emulsion and the digestibility of the emulsion was 16.93% in 120min. Compared with untreated cells, Pickering emulsion can effectively inhibit the proliferation of MCF-7 (52.71%). All these results indicate that OSA starch stabilized pepper essential oil can effectively increase solubility, improve stability, and expand the application range. Therefore, it can provide a theoretical basis for applications of pepper essential oil, especially for the functional drug application.

Quality of jujube wines fermented by different jujube varieties: Physicochemical parameters, antioxidant activity, non-volatile and volatile substances

The varieties of raw materials are significant to the quality of jujube wine. In this study, the physicochemical quality, antioxidant activity, non-volatile and volatile substances of different jujube wines were analyzed. The alcohol content of the different wines ranged from 12.70% (v/v) to 14.19% (v/v). Wine fermented by J60Z showed the highest alcohol content. ZHDZ-fermented wine was the yellowest and its color quality was the best. The main monomeric phenols in date wine are chlorogenic acid, epicatechin and catechin. DZ-fermented wine had the strongest DPPH, ABTS radical scavenging activity and FRAP. The organic acids in date wine were mainly succinic acid, malic acid and lactic acid. JUZ-fermented wine had the highest content of total free amino acids, essential amino acids, and sweet amino acids, which were 817.42, 53.23, and 751.01 mg/L, respectively. Seventy-nine volatile compounds were found in the nineteen jujube wines. Wine fermented by JUZ had the highest total volatiles content (8329.52 mg/L). Principal component analysis and sensory evaluation revealed that DZ-fermented date wine had the highest composite and sensory scores. Therefore, this study showed that DZ was more suitable for making jujube wine. This study provides theoretical guidance for screening suitable varieties for jujube wine fermentation.

Metabolomic characterization of human glioblastomas and patient plasma: a pilot study

Background Glioblastoma (GBM) is a clinically challenging primary brain tumor with poor survival outcome despite surgical resection and intensive chemoradiation. The metabolic heterogeneity of GBM can become biomarkers for treatment response, resistance, and outcome prediction. The aim of the study is to investigate metabolic distinctions between primary and recurrent GBM tissue and patient plasma to establish feasibility for metabolic profiling. Methods A single-center cohort study analyzed tissue and blood samples from 15 patients with GBM using untargeted metabolomic/lipidomic assays. Metabolomic, lipidomic, and biogenic amine analyses were conducted on GBM tissue and patient plasma at diagnosis and recurrence using untargeted mass spectrometry. The study utilized a small but longitudinally collected cohort to evaluate alteration in metabolites, lipids, and biogenic amines between specimens at diagnosis and recurrence. Results Exploratory analysis revealed significant alteration in metabolites, lipids, and biogenic amines between diagnostic and recurrent states in both tumor and plasma specimens. Notable metabolites differed at recurrence, including N-alpha-methylhistamine, glycerol-3-phosphate, phosphocholine, and succinic acid in tissue, and indole-3-acetate, and urea in plasma. Principal component analysis revealed distinct metabolomic profiles between tumor tissue and patient plasma. Distinct metabolic profiles were observed in GBM tissue and patient plasma at recurrence, demonstrating the feasibility of using metabolomic methodologies for longitudinal studies. One patient exhibited a unique tumor resistance signature at diagnosis, possibly indicating a high-risk metabolomic phenotype. Conclusions In this small cohort, the findings suggest the potential of metabolomic signatures of GBM tissue and patient plasma for risk stratification, outcome prediction, and the development of novel adjuvant metabolic-targeting therapies. The findings suggest metabolic discrepancies at diagnosis and recurrence in tissue and plasma, highlighting potential implications for evaluation of clinical response. The identification of significant changes in metabolite abundance emphasizes the need for larger studies using targeted metabolomics to validate and further explore these profiles.

New clinical approach in facial mild-moderate acne: Re-stabilization of skin microbiota balance with a topical biotechnological phytocomplex.

Dysbiosis of the skin microbiota has been identified as a key factor in the development of acne. This study was aimed to evaluate the effect of a facial cream gel containing a biotechnological phytocomplex, niacinamide and succinic acid on the bacterial diversity of subjects with mild-moderate acne and its clinical benefits due to microbiota changes. Open-label, clinical study in 44 subjects with mild-moderate acne treated with a facial cream gel for 8 weeks. Bacterial diversity was analyzed by 16S rRNA gene sequencing of skin samples. Clinical effects were evaluated using the IGA acne severity scale, biometric measurements, and safety. After 56 days of product's use, an increase in alpha and beta diversity was found (p < 0.01), with a decrease in the relative abundance of C. acnes (48.99% vs. 38.83%, p < 0.001). Regarding clinical results, a decrease in acne severity on the IGA scale (27.33%, p < 0.001), number of non-inflammatory and inflammatory lesions (respectively: 31.12%, p = 0.05; 42.27%, p < 0.001), amount of sebum (89.00%, p < 0.01) and erythema (15.35%, p < 0.01), was found. Responder analysis of the IGA score showed that 61.36% of patients improved by at least one point at day 56. The product was well tolerated throughout the study. The use of the facial cream gel on skin was effective in rebalancing the microbiota, inhibiting biofilm formation and other virulence factors, reducing the number of mild-moderate acne lesions and sebum secretion, and consequently improving acne's severity.

Unraveling phytoremediation mechanisms of the common reed (Phragmites australis) suspension cells towards ciprofloxacin: Xenobiotic transformation and metabolic reprogramming

Phytoremediation is an effective solution to treat pollution with antibiotic compounds in aquatic environments; however, the underlying mechanisms for plants to cope with antibiotic pollutants are obscure. Here we used cell suspension culture to investigate the distribution and transformation of ciprofloxacin (CIP) in common reed (Phragmites australis) plants, as well as the accompanying phenotypic and metabolic responses of plants. By means of radioactive isotope labelling, we found that in total 68 % of CIP was transformed via intracellular Phase I transformation (reduction and methylation), Phase Ⅱ conjugation (glycosylation), and Phase Ⅲ compartmentalization (cell-bound residue formation mainly in cell walls, 23 %). The reduction and glycosylation products were secreted by the cells. To mitigate stress induced by CIP and its transformation products, the cells activated the defense system by up-regulating both intra- and extra-cellular antioxidant metabolites (e.g., catechin, l-cystine, and dehydroascorbic acid), anti-C/N metabolism disorder metabolites (e.g., succinic acid), secreting signaling (e.g., nicotinic acid), and anti-stress (e.g., allantoin) metabolites. Notably, the metabolic reprogramming could be involved in the CIP transformation process (e.g., glycosylation). Our findings reveal the strategy of wetland plants to cope with the stress from CIP by transforming the xenobiotic compound and reprogramming metabolism, and provide novel insights into the fate of antibiotics and plant defense mechanisms during phytoremediation.

Multifunctional biomolecular corona-inspired nanoremediation of antibiotic residues.

Facing complex and variable emerging antibiotic pollutants, the traditional development of functional materials is a "trial-and-error" process based on physicochemical principles, where laborious steps and long timescales make it difficult to accelerate technical breakthroughs. Notably, natural biomolecular coronas derived from highly tolerant organisms under significant contamination scenarios can be used in conjunction with nanotechnology to tackling emerging contaminants of concern. Here, super worms (Tubifex tubifex) with high pollutant tolerance were integrated with nano-zero valent iron (nZVI) to effectively reduce the content of 17 antibiotics in wastewater within 7 d. Inspired by the synergistic remediation, nZVI-augmented worms were constructed as biological nanocomposites. Neither nZVI (0.3 to 3 g/L) nor worms (104 to 105 per liter) alone efficiently degraded florfenicol (FF, as a representative antibiotic), while their composite removed 87% of FF (3 μmol/L). Under antibiotic exposure, biomolecules secreted by worms formed a corona on and modified the nZVI particle surface, enabling the nano-bio interface greater functionality, including responsiveness, enrichment, and reduction. Mechanistically, FF exposure activated glucose-alanine cycle pathways that synthesize organic acids and amines as major metabolites, which were assembled into vesicles and secreted, thereby interacting with nZVI in a biologically response design strategy. Lactic acid and urea formed hydrogen bonds with FF, enriched analyte presence at the heterogeneous interface. Succinic and lactic acids corroded the nZVI passivation layer and promoted electron transfer through surface conjugation. This unique strategy highlights biomolecular coronas as a complex resource to augment nano-enabled technologies and will provide shortcuts for rational manipulation of nanomaterial surfaces with coordinated multifunctionalities.

A practical green methodology for metal extraction from electric arc furnace dust through Yarrowia lipolytica biolixiviant

The study addresses the management of electric arc furnace dust (EAFD) generated by steel manufacturers and the challenge of metal leaching from this waste. Recognizing the scarcity of rare earth elements (REEs) and the industrial importance of manganese, the study emphasizes the urgent need for their recovery from waste. The current study presents a green approach using a biolixiviant from Yarrowia lipolytica IBRC-M30168, with crude sunflower oil as a hydrophobic carbon source with buffering properties. LC-MS analysis reveals significant citric, malic, and succinic acids production, with the highest concentrations reaching 53.3, 17.4, and 1.0 g/l. Bioleaching experiments show biolixiviants with an initial pH of 7 and 80 g/l carbon source and 5.5 and 100 g/l outperform others, resulting in 92.4 %, 23.2 %, 19.6 %, and 84.8 %, 24.2 %, and 20.6 % of manganese, dysprosium, and erbium within 9 days, with a pulp density of 10 g/l at 60 °C and 140 rpm. The study also explores the potential for industrial adaptation, testing a higher pulp density of 50 g/l, which resulted in leaching of 65.7 %, 10.7 %, and 7.3 % for manganese, dysprosium, and erbium after 6 days. Ultimately, the study concludes that structural analyses of the residues provide added evidence for the bioleaching process’s effectiveness.

Inhibitors derived from wheat straw hydrolysate can affect the production of succinic acid by Actinobacillus succinogenes

Lignocellulosic biomasses are promising source of fermentative sugars for the production of succinic acid. The lignocellulosic matrix must be pretreated to make the sugars available for the fermentation, but the most tested operative conditions can generate inhibitors as acetic acid, furans, phenolic compounds. Inhibitors remained an obstacle for the implementation of succinic acid production starting from recalcitrant biomasses as wheat straw. Batch tests were performed at two starting concentrations of strain, sugars (glucose, glucose and xylose) and inhibitors (acetic acid and furfural) by comparing the fermentation in standard broth medium and hydrolysate. Notwithstanding the presence of acetic acid (52.5 mg/L) and furfural (15 mg/L), succinic acid was obtained at 9*10−2 ± 7*10−3 g/L by starting from wheat straw hydrolysate that contained glucose (1.1 g/L), xylose (0.4 g/L) and without additional nitrogen source. Therefore, the study highlighted that a more concentrated inoculum was able to reduce the synergistic effect of inhibitors at their highest concentrations. The results obtained may contribute to improve succinic acid production from the biomasses that have been under-exploited but abundantly available, as wheat straw, for which solutions must be found to solve the problem of inhibitors production or to mitigate its effect on the fermentation process.

Novel biomass-derived corrosion inhibitor based on maleic and succinic acid for mild steel in HCl solution

Developing a sustainable and environmentally friendly inhibitor remains an essential and challenging goal for corrosion control. Here, aminoamide molecules were synthesized from maleic and succinic acids and applied as a novel biomass-derived corrosion inhibitor for mild steel in an HCl solution. The modification process of these molecules can increase their anticorrosive capacity, a fact verified in gravimetric tests, where inhibitors (1) and (2) achieved inhibition efficiency of ∼90 % (2 h immersion and 1 × 10–3 mol L–1). XPS spectra, apparent activation energy increase with inhibitor addition, adsorption Gibbs free energy of the inhibitors, and theoretical calculations show that the adsorption of the inhibitors on the metal surface is physical. This work provides a viable alternative to using a novel biomass-derived corrosion inhibitor.

Toxicity, degradation and metabolic pathway of 4-chlorinephenol in Chlorella vulgaris

Environmental contamination by 4-chlorinephenol (4-CP) has received widespread attention due to its frequent detection and adverse environmental effects. The traditional water treatment approaches and equipment are relatively mature, making them easier to operate and maintain. However, 4-CP is particularly difficult to degrade using the technologies, often resulting in incomplete removal, secondary pollution, or high energy consumption. The present study explored the toxicity of 4-CP to Chlorella vulgaris and its removal mechanism in microalgae. The results revealed that the photosynthetic activity and the growth of C. vulgaris were inhibited at high-level 4-CP (≥ 60 mg/L) during the whole exposure period. The dry weight and Chlorophyll-a content of C. vulgaris in the 4-CP treatment at 90 mg/L were only 72.3 % and 72.1 % of the control group, respectively. The structure and function of C. vulgaris was dramatically impacted under 4-CP stress. Malondialdehyde content, superoxide dismutase and catalase activities were significantly increased under multiple 4-CP concentrations, rising by 217 %, 299 %, and 78 % at 90 mg/L 4-CP compared to the control. Additionally, the removal of 4-CP by C. vulgaris aligned more closely with the pseudo-first-order model than with the pseudo-second-order model. As 4-CP concentration rose from 10 to 90 mg/L, the 4-CP removal rate decreased from 86.0 % to 56.7 % and the half-life was increased from 5.419 to 7.673 d based on the pseudo-first-order kinetics of 4-CP removal by C. vulgaris. Biodegradation is the major pathway for 4-CP removal by C. vulgaris, accounting for 72.54 % of the total removal rate at 30 mg/L on the 6th day. A total of 5 metabolites were detected for 6-day cultivation, including 4-chlorocatechol, hydroquinone, pyrogallol, 1,4-benzoquinone and succinic acid. This work provided an insight into the removal mechanism and biodegradation pathway of 4-CP in C. vulgaris.

Advances in synthesis of succinic acid using yeast cell factories

Succinic acid is an important C4 platform compound that serves as a raw material for the production of 1,4-butanediol, tetrahydrofuran, and biodegradable plastics such as polybutylene succinate (PBS). Compared to the traditional petrochemical-based route that uses maleic anhydride as a raw material, the microbial fermentation method for producing succinic acid offers more sustainable economic value and environmental friendliness. Yeasts with good acid tolerance can achieve low-pH fermentation of succinic acid, significantly reducing the cost of product extraction. Therefore, constructing high-yield succinic acid yeast strains through metabolic engineering has garnered increasing attention. This paper systematically introduced the application value and market size of succinic acid, summarized the pathways and key enzymes involved in succinic acid synthesis in microorganisms, and elaborated on the latest research progress in the synthesis of succinic acid using yeast cell factories. It also presented the current status of succinic acid synthesis using non-food raw materials such as glycerol, acetic acid, lignocellulosic hydrolysate, and others as substrates by engineered yeast strains. Finally, the paper provided a prospect for low-pH succinic acid biomanufacturing based on yeast cell factories.

A mechanistic study on the alleged cellulose cross-linking system: Maleic acid/sodium hypophosphite

A combination of maleic acid and sodium hypophosphite as a durable press finishing agent has been reported as a safer but equally effective alternative to conventional formaldehyde-based cross-linking agents for applications in cellulose-based fiber and textile finishing. However, the mechanistic details of this system have not yet been fully elucidated to allow optimization of the conditions. Effective cross-linking treatment requires high curing temperatures of ≥160 °C, which enhances oxidative and thermal degradation of cellulose. In this work, the sequential steps of the cross-linking mechanism were investigated both with model compounds and cellulosic substrates. Extensive NMR studies on model compounds revealed several side reactions alongside the synthesis of the targeted cross-linkable moiety. As an alternative, to circumvent side reactions, a two-step procedure was used by synthesizing the cross-linker sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid in a well-defined pre-condensation reaction before application onto the cellulosic substrate. Further, the effect of the cross-linking treatment on the molecular weight distribution of cellulose was studied by gel permeation chromatography, which showed degradation due to maleic acid/sodium hypophosphite treatment. By using sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid and sodium hypophosphite, this degradation could be significantly limited.