Vine tea is documented in ancient Chinese books as having the function of promoting blood circulation. However, its effects and mechanisms remain unclear. The aim of this study was to comprehensively investigate the protective potential and mechanisms of vine tea in high-fat diet rat through a combination of in vivo and in vitro experiments. The efficacy of vine tea was evaluated using a high-fat diet rat model and an oxidized low-density lipoprotein-treated cell model, with physiological and biochemical indicators measured in rat serum and cell supernatants. Transcriptomics was utilized to investigate alterations mRNA expression following the administration of dihydromyricetin in cell model. Metabolomics and 16S rRNA sequencing was employed to examine changes in metabolites in the serum and changes in gut microbiota of high-fat diet rats after administering vine tea extract. Vine tea extract and dihydromyricetin can reduce elevated levels of lipids, including total cholesterol and triglycerides, following modeling. Transcriptomic data indicate that dihydromyricetin exerts its effects by regulating ferroptosis signaling pathways. Metabolomic analysis demonstrates that the administration of vine tea extract influences the vitamin K cycle and glutathione, thereby alleviating the progression of ferroptosis. Additionally, 16S rRNA sequencing reveals that vine tea extract increases Lactobacillaceae in the gut microbiota, which subsequently affects the levels of lysophosphatidylcholine, a major phospholipid component of oxidized low-density lipoprotein in serum. Our results indicate that vine tea can regulate ferroptosis signaling pathways and increase Lactobacillaceae in the gut microbiota, thereby exhibiting cardiovascular protective effects in high-fat diet rats.

Vitrimer curing temperatures typically exceed their fully cured glass transition temperature (Tg), limiting their compatibility with heat-sensitive materials. Herein, a heat-resistant, recyclable polyimine vitrimer is synthesized below the fully cured Tg by using polyethyleneimine replacing the commonly used tris(2-aminoethyl)amine as a crosslinker. It attains a gel content of 99 % upon curing at 120 degrees C, while exhibiting a Tg of 155 degrees C, a thermal expansion coefficient comparable to thermosets (33.8 mu m m- 1 degrees C- 1), and a 5 % weight-loss temperature of 279 degrees C. Moreover, 99 % of tensile strength is retained after recycling. This mild curing behavior arises from a solvent-thermal synergistic network evolution mechanism that differs from conventional thermosets. Before solvent removal, polyethyleneimine shows higher reaction kinetics than tris(2-aminoethyl)amine, which promotes a more rapid evolution from oligomers to a crosslinked network. The solvent's plasticizing effect maintains a diffusion-unconstrained state of the network, enabling its sustained growth. After solvent removal, a continuous high-crosslinked network with dispersed low-crosslinked domains is formed, yielding a gel content of 90 %. Subsequent mild heating (120 degrees C) activates segmental mobility in low-crosslinked domains, enabling their integration into the continuous high-crosslinked network and completing curing. In contrast, tris(2-aminoethyl) amine systems require 180 degrees C to activate segmental mobility within the discontinuous high-crosslinked domains, enabling interdomain crosslinking to achieve full curing. These findings provide novel network evolution routes and strategies for mild curing of heat-resistant vitrimers.

Taxus renewable twigs produce valuable taxanes, notably anticancer drug paclitaxel and its key intermediates, including 10-deacetylbaccatin III (10DAB), baccatin III (B-III), and 10-deacetyltaxol (10DAT). However, incomplete understanding of taxane biosynthetic networks and their regulatory mechanisms across species and developmental stages limits targeted genetic improvement of these medicinal plants. Here, we integrated metabolomics and transcriptomics to analyze taxane accumulation and associated biosynthetic gene expression patterns in three high-yielding (10DAB- or paclitaxel-rich) Taxus accessions (HZDNF, HZDDB, HZDMDY) twigs across developmental stages grown under uniform environmental conditions. Our study identified 55 distinct taxanes and 140 differentially expressed genes (DEGs) related to paclitaxel biosynthesis, enabling construction of relatively comprehensive metabolic networks and gene co-expression patterns. The HZDNF variety, particularly its young twigs (NF-new), showed exceptional production of most 6/8/6/4-taxanes (including 10DAB, B-III, and 10DAT), outperforming other varieties. This correlated with elevated expression of 42 potentially biosynthetic genes, including 10 putative rate-limiting enzyme genes. Furthermore, weighted gene co-expression network analysis (WGCNA) revealed 34 core DEGs from the above-mentioned 42 candidates, along with 13 potential master transcriptional factors (TFs). These TFs might enhance core DEGs expression via direct or indirect means, thereby boosting 10DAB/B-III/10DAT accumulation and high yield. Subsequent functional verification for two representative TFs of 13 candidates through transient overexpression, confirmed that two novel TFs (bHLH-16 and zf-HD-6) significantly enhance 10DAB/10DAT production by activating key DEGs (T7βOH-1, T10βOH-2 and BAPT-2). These findings advance understanding of taxane biosynthesis (especially 10DAB, B-III and 10DAT), providing targets for metabolic engineering of taxanes and Taxus germplasm improvement.

Microbial degumming offers an eco-friendly alternative to chemical methods for ramie fiber production, but industrial application is constrained by low efficiency stemming from limited mechanistic insight. This study systematically investigates the process using Pectobacterium carotovorum HG-49. Strain HG-49 showed a lag phase of 0-4 h, a logarithmic phase of 6-10 h, and peak biomass at 12 h. Pectin (97.05%) and water-soluble substances (98.45%) were nearly fully removed, whereas hemicellulose removal was only 73.54%, rendering it the primary residual gum component. Pectinase activity peaked at 120.75 U/mL, while mannanase (35.85 U/mL) and xylanase (30.20 U/mL) reached roughly one-quarter of that level; cellulase activity remained minimal. Scanning electron microscopy (SEM) indicated that 6-12 h constituted the main gum degradation phase. Fourier transform infrared spectroscopy (FTIR) and micro-FTIR showed progressive decreases in pectin, hemicellulose, and lignin absorption peaks with degumming. X-ray diffraction (XRD) revealed increased crystallinity from 72.07% to 80.02%, and thermogravimetric analysis (TGA) showed elevated degradation temperature from 417 °C to 435 °C. Collectively, these data confirm progressive removal of gummy substances and enhanced cellulose purity. Transcriptomic profiling further revealed that low abundance and reduced expression of hemicellulases significantly limited degumming performance. Therefore, enhancing efficiency should focus on: supplementing pectin-rich substrates to accelerate bacterial proliferation and enzyme production, broadening the hemicellulase spectrum and enhancing catalytic activities and establishing effective pretreatment protocols for ramie bast. These findings provide a theoretical foundation for improving microbial degumming efficiency and advancing industrial feasibility.

Hemsleya ellipsoidea (Xuedan) is a phylogenetically distinct medicinal species within the Cucurbitaceae family, notable for its ability to accumulate cucurbitacin IIa-a bioactive triterpenoid with potent anti-inflammatory and antibacterial activities. Here, we present a chromosome-scale reference genome for H. ellipsoidea, assembled using Oxford Nanopore, Illumina, and Hi-C sequencing technologies. The 535.68 Mb genome, with a contig N50 of 15.36 Mb, encodes 25 230 protein-coding genes across 14 pseudo-chromosomes, of which 63.85% comprise repetitive elements. Comparative genomic and phylogenomic analyses reveal that H. ellipsoidea diverged early (~84.7 MYA) from other cucurbits, maintaining several ancestral chromosomal segments but exhibiting lineage-specific rearrangements, reflecting an independent evolutionary trajectory without recent whole-genome duplication. Two conserved but functionally specialized biosynthetic gene clusters related to cucurbitacins formation were identified, suggesting coordinated regulation of triterpenoid metabolism. Integration of genomic and transcriptomic data enabled the reconstruction of the cucurbitacin IIa biosynthetic pathway and the identification of key structural enzymes and transcription factors. Distinct tissue-specific expression patterns further indicate root-localized synthesis and accumulation of cucurbitacin IIa. Collectively, this work provides the first high-quality genome of a medicinal Cucurbitaceae species and offers new insights into the chromosomal evolution, metabolic specialization, and adaptive diversification of H. ellipsoidea. The genomic resource also lays a foundation for functional genomics, metabolic engineering, and molecular breeding toward high-value triterpenoid production.

Plastic waste presents an escalating environmental threat. Using cellulosic fibers and vitrimers to develop recyclable biocomposites offers a promising strategy to decrease plastic wastes. However, these biocomposites currently struggle to combine high strength with heat resistance, limiting their suitability for structural materials. This challenge arises because a heat-resistant vitrimer matrix requires curing at high temperature for hours, which damages fibers. This study employed high-functionality polyethyleneimine containing secondary amine groups as a crosslinker, replacing the conventionally used low-functionality tris(2-aminoethylamine) lacking secondary amines, both enabling complete curing of a ramie fiber-reinforced polyimine biocomposite (RY-PIPEI) under mild conditions and inducing the formation of a multiple hydrogen-bonding network. RY-PIPEI exhibited a tensile strength of 219 MPa, which exceeds that of most reported thermoplastic-, thermoset-, and vitrimer-based biocomposites used for structural applications. Compared with representative biocomposites exhibiting the highest tensile strength in each matrix category, RY-PIPEI demonstrated superior heat resistance, with a glass transition temperature of 174 degrees C and a thermal expansion coefficient of 3.97 mu m m-1 degrees C-1. Furthermore, RY-PIPEI retained over 90% of original tensile strength after lamination, self-healing, and recycling, and lost 87% of mass after one year of soil burial, features that were not achieved by these representative biocomposites. In practical demonstrations, a box fabricated from RY-PIPEI was able to support 23,200 times its own weight and withstand 100 compression cycles. A drift board made from RY-PIPEI was suitable for adult exercise. These properties rendered RY-PIPEI a lightweight structural material suitable for construction and sports-related applications, supporting progress toward zero plastic pollution.

To address the high pollution burden of chemical degumming for ramie fibers and the low efficiency of microbial methods, this study developed a novel synergistic degumming system employing pectate lyase in conjunction with potassium peroxy(mon)sulfate (PPMS). Based on enzymatic characterization, reducing sugar analysis, and immunofluorescence results, pectate lyase (PcPel1834) was identified as the crucial enzyme in degumming strain Pectobacterium carotovorum HG-49. The enzyme exhibited high catalytic efficiency (4980 U/mg, Kcat/Km = 1588.92 mL·s-1·mg-1), and its degumming performance was comparable to that of commercial pectate lyase. The 6.5 h treatment combining PcPel1834 and PPMS, achieved total gum removal rate of 88.72%, bundle breaking tenacity of 5.10 cN/dtex and whiteness of 52.7, meeting the first-class textile criteria of China. The degumming mechanism of the synergistic system was elucidated via immunofluorescence, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and gas chromatography-mass spectrometry (GC/MS) analysis. PcPel1834 efficiently degraded pectin and deconstructed the compact bundle structure of ramie bast fibers. This facilitated PPMS in generating a strong oxidative environment rich in oxygen free radicals, which degraded hemicellulose and lignin into small-molecule acids, benzoic acid and aromatic hydrocarbon fragments. This study established an efficient and eco-friendly degumming paradigm for ramie industry.

Pectate lyases are promising industrial biocatalysts, but limited thermostability restricts their practical use. Here, we developed a multidimensional consensus computational framework integrating sequence conservation, structural dynamics, and thermodynamic prediction to identify functional mutation hotspots in PcPel1834. Iterative saturation mutagenesis yielded M5 (S212E/Q225L/F241L/L260A/G296T), which showed markedly enhanced thermostability and moderately improved apparent catalytic efficiency. M5 increased the melting temperature from 52.1 to 65.0 °C and retained nearly full activity after 24 h at 50 °C. Its specific activity and kcat/Km reached 4259 U/mg and 1427 mL/s/mg, respectively, both higher than WT. Epistatic analysis and MD simulations indicated that M5 enhanced thermostability through hydrogen-bond remodeling, backbone rigidification, and strengthened long-range communication, while distal mutations allosterically preorganized the catalytic pocket to improve substrate binding and catalytic geometry. In ramie degumming, M5 showed improved pectin removal and fiber quality. This study provides a practical strategy for engineering thermostable pectate lyases with improved catalytic performance.

BACKGROUND:Hyperuricemia (HUA) involves multi-organ dysfunction, particularly hepatic and renal abnormalities. Danggui-Niantong decoction (DGN) is a traditional formula for gout and chronic kidney disease. Clinically, DGN is often combined with drugs that regulate hepatic function to treat HUA. Anoectochilus roxburghii (AR) is recognized for its hepatoprotective properties. However, whether the AR and DGN combination (AR+DGN) exerts superior urate-lowering and organ-protective effects compared to monotherapy, and the mechanisms underlying this combined treatment, remain unclear. PURPOSE:This study aimed to evaluate the therapeutic efficacy of AR, DGN, and AR+DGN in hyperuricemic rats, and to investigate the mechanisms of this combined action via integrated gut microbiota and metabolomics analyses. METHODS:First, the active components and fingerprints of AR and DGN were characterized using UPLC-MS and HPLC. A hyperuricemic model was established in male Sprague-Dawley rats via a high-purine diet. Following a preliminary experiment to determine the optimal AR dose (n = 30), 48 rats were randomized into six groups (n = 8): Control, HUA, Benzbromarone (Ben), AR, DGN, and AR+DGN. After 4 weeks of intragastric administration, therapeutic efficacy was assessed via serum uric acid (SUA), hepatorenal function markers, and histopathology. Subsequently, 16S rRNA sequencing and untargeted metabolomics were employed to screen potential signaling pathways, which were further validated by western blot, immunofluorescence, and RT-qPCR. RESULTS:A total of 296 compounds were identified collectively across the AR and DGN extracts, and ten bioactive markers, including kinsenoside, chlorogenic acid, and isoimperatorin, were rigorously quantified for quality standardization. Compared to monotherapy, AR+DGN provided dual protection by restoring both hepatic and renal functions and demonstrated a superior urate-lowering capacity, reducing SUA levels by 58.2% and serum alanine aminotransferase levels by 59.6% compared to the HUA group (p < 0.01), while maintaining normal liver enzyme levels unlike benzbromarone. Mechanistically, AR+DGN restored gut microbiota dysbiosis in hyperuricemic rats, notably enriching seven beneficial genera (e.g., Alistipes and Bifidobacterium) while depleting four pathogenic genera (e.g., Escherichia-Shigella and Coriobacteriaceae_UCG_002). Furthermore, elevated levels of beta-nicotinamide mononucleotide, propionate, butyrate, and isobutyrate, along with reduced inosine and xanthine, were identified as key metabolites significantly associated with these microbial alterations (p < 0.05). KEGG analysis identified NAD+ metabolism and purine metabolism as key pathways co-regulated in both serum and intestinal contents. Critically, AR+DGN upregulated hepatic NAD+ biosynthetic enzymes (QPRT, NMNAT3, and NAMPT by 1.74-, 2.64-, and 1.79-fold, respectively), thereby boosting liver and serum NAD+ levels. This metabolic restoration, coupled with a 62.5% reduction in hepatic reactive oxygen species, indicated the disruption of the uric acid-oxidative stress positive feedback loop. Simultaneously, AR+DGN restored renal urate transport balance by inhibiting reabsorptive transporters (GLUT9, URAT1) while upregulating the secretory transporter (ABCG2), ultimately contributing to the significant urate-lowering efficacy. CONCLUSIONS:This study demonstrates that AR+DGN exerts superior urate-lowering efficacy and hepatorenal protection. Mechanistically, it functions by remodeling the gut microbiota-metabolic axis to regulate hepatic NAD+ metabolism and renal urate transport, supporting its potential for the safe and long-term management of HUA.

Zhangjiajie vine tea, derived from Ampelopsis grossedentata, is a characteristic product with pharmacological benefits for heat clearance, detoxification, liver calming, and blood pressure reduction. The content of dihydromyricetin (DMY), the primary active compound, directly affects product quality, yet the regulatory genes associated with high DMY contents remained to be determined. In this study, a total of 164 vine tea germplasms collected from Zhangjiajie were revealed to exhibit substantial variation in DMY contents, ranging from 13.96 to 41.56

Pyracantha fortuneana fruit is traditionally consumed as a dietary supplement in China known for its benefits in blood nourishment. Thrombocytopenia is often associated with blood deficiency. However, scientific studies on the platelet-enhancing activity of P. fortuneana fruit are lacking. This study investigates the protective effects of P. fortuneana fruit extract (PFE) against chemotherapy-induced thrombocytopenia (CIT) and elucidates molecular mechanisms underlying its platelet-enhancing effects. Results showed that PFE, particularly its ethyl acetate fraction (PFEEA), significantly increased platelet counts by 48.7 %, reduced bleeding and clotting times, and decreased bleeding volume. PFEEA also mitigated organ injuries and lowered serum alanine transaminase levels. Transcriptomic analysis revealed upregulation of genes enriched in the hematopoietic cell lineage pathway by PFEEA, along with normalization of hematopoiesis-related cytokine levels and thrombopoietin mRNA expression in the liver. This study establishes PFE's potential against CIT and provides insights into its mechanisms, supporting its application as a functional food.

Bio-degumming is an eco-friendly and energy-efficient method for removing non-cellulosic matrices to extract ramie fiber, while it still requires prolonged processing and remains partial gums with complex side chains. This study demonstrated that, following pectin depolymerization, partial xylan and mannan in the middle lamella and phloem parenchyma could be removed in their non-depolymerized forms. Thus, the bio-degumming process followed by mechanical beating was improved by an alternating approach. Ramie bast was first beaten to loosen the middle lamella and phloem parenchyma, aiding pectinase, xylanase, and mannanase binding to internal gums. These enzymes then partially degraded the gum, weakening gum-fiber connections. Additional beating removed these loosened tissues, accelerating primary wall exposure. This approach reduced the blocking effect of gum laminated junctions, shortening degumming time. Afterward, carbohydrate binding domains further weakened the hindering effect of side chains and enhanced endoxylanase and endomannanase to remove residual hemicellulose on the primary wall. Furthermore, the engineered Pectobacterium carotovorum HG-49 capable of constitutively expressing and secreting the fusion proteins of endoxylanase, endomannanase, and carbohydrate binding domains was built. The alternating treatment with the engineered HG-49 and mechanical beating reduced degumming time from 16 to 12 h, decreased residual gum content from 6.34 to 4.48

ABSTRACTBranched polyethyleneimines (B‐PEIs) have been widely used in industries and researches, such as the papermaking, water treatment, and enzyme immobilization. However, they exhibit a complex composition, leading to ambiguity in understanding the B‐PEIs' synthetic process and relevant influencing factors. Additionally, no representative molecule of B‐PEIs has been identified, leading to subjective selections when studying structure–performance relationships. This study focused on three commercially low‐molecular‐weight B‐PEIs: 300, 600, and 1800. It identified that they primarily consisted of C, H, and N elements in the form of methylene and primary, secondary, and tertiary amine groups. The ratios of amine groups were also revealed, offering guidance for application. Moreover, the types of polymerization degrees and their proportions were determined, with the free ends identified as primary amino groups. Based on these, this study proposed synthetic processes and potential influencing factors. This provided valuable insights into the synthesis of B‐PEIs with varying compositions and properties. Furthermore, the stability of over 527 potential molecular structures was calculated. By weighing above features, the representative model molecules used to analyze B‐PEIs' structure–performance relationships was identified. These results had significant implications for the synthesis, application, and functional analysis of B‐PEIs.

C21 steroids represent essential precursors for the industrial synthesis of corticosteroids, yet their conventional manufacturing processes are hampered by suboptimal efficiency and substantial environmental burdens. In this study, we established a biocatalytic route to synthesize the pivotal C21 steroid precursor 16-dehydroprogesterone (16-DPG) from diosgenin, employing an engineered strain, Mycolicibacterium sp. HK-90. Key metabolic engineering strategies included (i) targeted knockout of kstD and kshA genes to disrupt the steroid core degradation pathway, generating the chassis strain mHust-Delta kstD-Delta kshA. This modification prevented diosgenin degradation while enabling its conversion to C19 steroid 4-androstenedione (4-AD) via C21 steroid intermediates. (ii) Identification and characterization of a Baeyer-Villiger monooxygenase (BV-2539) as the key enzyme mediating C21-to-C19 steroid conversion during diosgenin catabolism. Subsequent inactivation of BV-2539 in mHust-Delta kstD-Delta kshA completely abolished 4-AD, thereby redirecting diosgenin catabolism toward the accumulation of 16-DPG. (iii) Discovery and knockout of a transcriptional repressor (IclR-2535) significantly constrained the production yield. The resulting engineered strain, mHust-C21, efficiently synthesized 33.80 g/L 16-DPG (89.7% molar yield) from 50 g/L diosgenin under optimized cultivation conditions. The synthesis pathway achieves a yield far exceeding those of conventional processes while eliminating toxic Cr(VI) oxidants and streamlining production steps. This work offers a novel strategy for the sustainable manufacturing of 16-DPG.

Tea aroma critically influences consumer preference. Pantoea camelliae Z09, isolated from Yunnan sun-dried green tea, enhances the rose-honey aroma of fermented tea infusion. This study investigated aroma formation during liquid-state fermentation using GC-MS, GC-IMS, and molecular docking. GC-MS and GC-IMS identified 223 and 74 volatile organic compounds (VOCs), respectively, including alcohols, ketones, and esters. Six key aroma-active compounds were identified via relative odor activity value (ROAV), while orthogonal partial least squares discriminant analysis (OPLS-DA) revealed 49 differential VOCs driving aroma evolution. By integrating ROAV, OPLS-DA, abundance analysis, and molecular docking, 29 major VOCs were linked to the rose-honey profile, with phenylethyl alcohol as the dominant contributor. Their binding to olfactory receptors involved noncovalent interaction. A flavor wheel was constructed to visualize the aroma profile. This study is the first to elucidate how bacteria influence the aroma of tea infusion through liquid-state fermentation, offering insights for the development of specialty tea products.

Diosgenin is a key precursor for steroidal pharmaceuticals; however, traditional acid hydrolysis produces significant environmental pollution, whereas enzymatic conversion presents a more environmentally sustainable alternative. Herein, four saponinases were identified from Aspergillus tubingensis HG57: the β-glucosidases ATGH I and ATGH II, which hydrolyzed residual β-d-glucosyl moieties, and the rhamnosidases ATRH I and ATRH II, which cleaved terminal α-L-(1 → 2) rhamnosyl linkages in steroidal saponins. ATGH I (7.46 U mg-1) and ATRH I (285.31 U mg-1) demonstrated some of the highest catalytic efficiencies documented to date. Both enzymes displayed broad pH tolerance and thermostability (≤50 °C), with ATRH I maintaining over 90 % activity in 2 M rhamnose. Structure-guided engineering of ATGH I led to the development of an improved variant, ATGH M, which displayed a two-fold improvement in catalytic efficacy (14.99 U mg-1). High-density fermentation produced enzyme-rich supernatants (ATGH M: 98.52 U mL-1; ATRH I: 2564.36 U mL-1) that facilitated gram-scale, one-pot enzymatic hydrolysis to produce diosgenin. This bioprocess achieved 138 % of the diosgenin yield obtained by traditional acid hydrolysis while markedly reducing wastewater pollutants, lowering chemical oxygen demand by 76 %, sulfate by 99 %, and acidity by nearly 100 %. The integration of efficient saponinase discovery, protein engineering, and high-density fermentation established a green and scalable enzymatic platform for diosgenin production, offering a sustainable alternative to conventional acid hydrolysis.

Microbial degumming for producing ramie fiber has emerged as mainstream method owing to its eco-friendliness and low energy-consumption, however, its efficiency requires further improvement. This study proposed a synergistic approach to improve degumming efficiency by enhancing xylanase activity in Pectobacterium carotovorum HG-49 and optimizing pretreatment through ammonium oxalate soaking combined with microwave heating for ramie bast fibers. The pretreatment separated and dissolved most pectin, loosened the fiber structure, and provided ammonium oxalate as nitrogen source, thereby promoting HG-49 growth and enhancing its production of degradation enzymes. Therefore, the degumming time shortened by 2 h, the removal ratio of hemicellulose and total gum increased by 10.78% and 5.93%, respectively. The achieved gum removal rate of 87.33% within 14 h represents one of the highest values reported to date. This study demonstrated that synergistic action of enhanced xylanase activity and optimized pretreatment greatly improved the microbial degumming efficiency for ramie bast fibers.

Commercially ripened Pu-erh teas (CRPTs) exhibit a complex flavor profile that poses challenges to standardized production. This study combines traditional sensory evaluation with electronic tongue technology to assess the overall flavor and taste attributes of CRPTs both qualitatively and quantitatively. Multivariate statistical techniques, including Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Partial Least Squares Discriminant Analysis (PLS-DA), were used to classify the samples into four categories: Heavy and Thick (HT_CRPT), Heavy and Mellow (HM_CRPT), Mellow and Thick (MT_CRPT), and Mellow and Light (ML_CRPT). HT_CRPT exhibits the highest richness, HM_CRPT demonstrates the greatest astringency and aftertaste-A with the least sweetness (p < 0.05), MT_CRPT presents the most umami and the least richness, while ML_CRPT has the lowest levels of astringency, umami, and bitterness (p < 0.05). CRPTs vary in liquid color from brownish-red to reddish-brown, with HM_CRPT exhibiting the darkest hue, characterized by L* and a* values of 56.15 ± 2.56 and 30.93 ± 1.85, respectively. The principal chemical components of CRPTs encompass theabrownins, phenylpropanoids, polyketides, lipids, and lipid-like molecules. A total of 282 metabolites, including (-)-Epigallocatechin 3,4'-di-gallate, flavonol 3-O-D-glucoside, and isorhamnetin 4'-O-glucuronide significantly influence the flavor of CRPTs (VIP > 1 and p < 0.05). 24 and 35 components underlie liquid color and taste, respectively, with taste compounds interacting with taste receptors primarily through van der Waals forces and hydrogen bonding. A flavor wheel was developed to illustrate in detail the classification criteria and flavor compounds of various CRPTs. The findings establish a scientific foundation for the development of a standardized evaluation system for CRPTs and the creation of a diverse range of products.

Ripened Pu-erh tea (RPT) is renowned for its distinctive flavor and health benefits. However, its complex fermentation process poses challenges in ensuring consistency in production. This study investigated RPT flavor formation through sensory evaluation, multi-omics analysis, and multivariate statistical approaches. By day 24, the tea exhibited a reddish-brown infusion and a mellow, thick taste (MT_RPT), achieving the highest sensory score (94.0, P < 0.05). Sixteen flavor-related chemical components exhibited significant changes (P < 0.05). The contents of free amino acids, L-theanine, tea polyphenols, flavonoids, catechins, and thearubigins decreased. In contrast, the contents of total soluble sugars, caffeine, theobromine, epicatechin, and theabrownins (TBs) increased, reaching 74.1 mg/g, 65.38 mg/g, 3.13 mg/g, 3.33 mg/g, and 134.84 mg/g, respectively. Additionally, 33 nonvolatile metabolites (e.g., pelargonidin 3-O-glucoside, dihydroisorhamnetin, and puerarin) were significantly correlated with MT_RPT flavor (VIP > 1, |r| ≥ 0.8, P < 0.05) and influenced by key functional microbes, including Pantoea, Aspergillus, Brachybacterium, and Staphylococcus. By day 30, the infusion darkened, and sensory scores declined (81.4, P < 0.05), attributed to the dominance of Brevibacterium. This microbial shift reduced water-soluble pectin, free amino acids, and 11 metabolites while increasing TBs and theophylline (219.33 mg/g and 0.09 mg/g, respectively). Therefore, TBs were identified as a crucial indicator of optimal fermentation. Moreover, redundancy analysis indicated that the tea pile's central temperature, moisture content, and pH were essential fermentation parameters (P < 0.05). These findings deepen our understanding of MT_RPT flavor development mechanisms and provide valuable insights into precise fermentation control.

Global sustainable development necessitates transitioning to a renewable bioeconomy with a reduced carbon footprint. Xylose is the second most abundant component of second-generation biomass, but it has a low atomic economy for producing C3 chemicals, resulting in an abundance of unused xylose from lignocellulose. This limitation can be addressed by coupling it with C1 compounds from third-generation biomass. Although native metabolic pathways like the RuMP and XuMP cycles are efficient in vivo, their industrial application can present challenges due to issues such as formaldehyde toxicity and the complexity of metabolic regulation. Here, we present an innovative in vitro coupling pathway: the xylose and methanol integrated L-lactate production pathway (XMLP). The XMLP efficiently couples glycolaldehyde, produced from xylose via the Dahms pathway, with C1 formaldehyde, achieving a theoretical carbon yield of 100 %. After pathway design and systematic screening of enzymatic components, we optimize the rate-limiting formolase (FLS-M3), resulting in a 3.4-fold improvement in kcat/Km. Further optimization of reaction conditions leads to an 88.75 % carbon atom conversion efficiency and an L-lactate concentration of 6 g/L from an input of 25 mM xylose. Additionally, using methanol directly in a cascade reaction, we achieve an L-lactate concentration of 5.85 g/L from the same xylose input. This study not only provides an efficient strategy for L-lactate synthesis but also demonstrates the scalability and versatility of the XMLP-a robust platform for the co-production of valuable C3 chemicals from CO2 and lignocellulosic biomass that provides a new approach for carbon-neutral manufacturing.