High internal phase emulsions gel ink for direct-ink-writing 3D printing of liquid metal.

3D printing of liquid metal remains a big challenge due to its low viscosity and large surface tension. In this study, we use Carbopol hydrogel and liquid gallium-indium alloy to prepare a liquid metal high internal phase emulsion gel ink, which can be used for direct-ink-writing 3D printing. The high volume fraction (up to 82.5%) of the liquid metal dispersed phase gives the ink excellent elastic properties, while the Carbopol hydrogel, as the continuous phase, provides lubrication for the liquid metal droplets, ensuring smooth flow of the ink during shear extrusion. These enable high-resolution and shape-stable 3D printing of three-dimensional structures. Moreover, the liquid metal droplets exhibit an electrocapillary phenomenon in the Carbopol hydrogel, which allows for demulsification by an electric field and enables electrical connectivity between droplets. We have also achieved the printing of ink on flexible, non-planar structures, and demonstrated the potential for alternating printing with various materials.

Molecular mechanism of saturated aldehyde oxidation: A DFT insight into volatiles forming from decanal thermal oxidation.

Decanal is one of the main products of lipid oxidation. It has been shown that decanal can oxidize to form volatiles with shorter carbon chains during heating, but the mechanism is still unclear. In this study, volatile compounds formed in the decanal thermal oxidation were verified using thermal-desorption cryo-trapping combined with GC-MS. A total of 32 volatile compounds were identified. The oxidation mechanism of decanal was studied by applying density functional theory. Results revealed that the carbonyl carbon atom was the thermal oxidation site of decanal and two pathways of peroxide oxidation were determined: the ortho­carbon and the meta­carbon oxidation. The ortho­carbon oxidation pathway is superior to the occurrence of the meta­carbon oxidation pathway. The oxidative mechanism of decanal was finally summarized as the peroxide oxidation based on radical attack on the carbonyl carbon, which would provide a theoretical basis for exploring the oxidation mechanism of other saturated aldehydes.

Novel microbial fermentation for the preparation of iron-chelating scallop skirts peptides-its profile, identification, and possible binding mode.

Iron chelating peptides have been widely utilized as iron supplements due to their excellent absorption capacity, However, the high cost and cumbersome manufacturing process of these peptides significantly limit their industrial application. In this study, fermentation was used for the first time to prepare iron chelating peptides. Bacillus altitudinis 3*1-3 was selected as the most suitable strain from 50 strains. The hydrolysates of fermented scallop skirts showed excellent iron-chelating capacity (9.39 mg/g). Aspartic acid, glutamic acid, and histidine are crucial for the binding of peptides to ferrous ions. The heptapeptide (FEDPEFE) forms six binding bonds with ferrous irons. Compared with ferrous sulfate, peptide-ferrous chelate showed more stability in salt solution and simulated gastrointestinal juice (p < 0.05). Furthermore, the fermentation method could save >50% of the cost compared with the enzymatic method. The results can provide a theoretical basis for the preparation of ferrous-chelated peptides using the fermentation method.

Effects of quercetin- and Lactiplantibacillus plantarum-containing bioactive films on physicochemical properties and microbial safety of grass carp.

In this study, the electrospinning technique was used to co-encapsulate Quercetin (Qu) and Lactiplantibacillus plantarum 1-24-LJ in PVA-based nanofibers, and the effect of bioactive films on fish preservation was evaluated at the first time. The findings indicated that both Lpb. plantarum 1-24-LJ and Qu were successfully in the fibers, and co-loaded fibers considerably outperformed single-loaded fiber in terms of bacterial survival and antioxidant activity. Following fish preservation using the loaded fibers, significant reductions were observed in TVB-N, TBARS, and microbial complexity compared to the control group. Additionally, the co-loaded fibers more effectively reduced the counts of H2S-producing bacteria and Pseudomonas. In the future, fibers with both active substances and LAB hold promise as a novel approach for fish preservation.

Comparison of downsizing strategy (HANGZHOU Solution) and standard annulus sizing strategy in type 0 bicuspid aortic stenosis patients undergoing transcatheter aortic valve replacement: Rationale and design of a randomized clinical trial.

BACKGROUND: There has not been a consensus on the prothesis sizing strategy in type 0 bicuspid aortic stenosis (AS) patients undergoing transcatheter aortic valve replacement (TAVR). Modifications to standard annular sizing strategies might be required due to the distinct anatomical characteristics. We have devised a downsizing strategy for TAVR using a self-expanding valve specifically for patients with type 0 bicuspid AS. The primary aim of this study is to compare the safety and efficacy of downsizing strategy with the Standard Annulus Sizing Strategy in TAVR for patients with type 0 bicuspid AS. TRIAL DESIGN: It is a prospective, multi-center, superiority, single-blinded, randomized controlled trial comparing the Down Sizing and Standard Annulus Sizing Strategy in patients with type 0 bicuspid aortic stenosis undergoing transcatheter aortic valve replacement. Eligible participants will include patients with severe type 0 bicuspid AS, as defined by criteria such as mean gradient across aortic valve ≥40 mmHg, peak aortic jet velocity ≥4.0 m/s, aortic valve area (AVA) ≤1.0 cm², or AVA index ≤0.6 cm2/m2. These patients will be randomly assigned, in a 1:1 ratio, to either the Down Sizing Strategy group or the Standard Sizing Strategy group. In the Down Sizing Strategy group, a valve one size smaller will be implanted if the "waist sign" manifests along with less than mild regurgitation during balloon pre-dilatation. The primary end point of the study is a composite of VARC-3 defined device success, absence of both permanent pacemaker implantation due to high-degree atrioventricular block and new-onset complete left bundle branch block. CONCLUSION: This study will compare the safety and efficacy of Down Sizing Strategy with the Standard Annulus Sizing Strategy and provide valuable insights into the optimal approach for sizing in TAVR patients with type 0 bicuspid AS. We hypothesize that the Down Sizing Strategy will demonstrate superiority when compared to the Standard Annulus Sizing Strategy. (Down Sizing Strategy (HANGZHOU Solution) vs Standard Sizing Strategy TAVR in Bicuspid Aortic Stenosis (Type 0) (TAILOR-TAVR), NCT05511792).

Monitoring the yeasts ecology and volatiles profile throughout the spontaneous fermentation of Taggiasca cv. table olives through culture-dependent and independent methods.

Taggiasca table olives are typical of Liguria, a Northwestern Italian region, produced with a spontaneous fermentation carried out by placing the raw drupes directly into brine with a salt concentration of 8-12 % w/v. Such concentrations limit the development of unwanted microbes and favor the growth of yeasts. This process usually lasts up to 8 months. Yeasts are found throughout the entire fermentation process and they are mainly involved in the production of volatile organic compounds, which strongly impact the quality of the final product. The aim of this study was to evaluate the dynamics of autochthonous yeasts in brines and olives in a spontaneous process with no lye pre-treatment or addition of acids in the fermenting brine with 10 % NaCl (w/v) in two batches during 2021 harvest. Three hundred seventy-three yeast colonies were isolated, characterized by rep-PCR and identified by the D1/D2 region of the 26S rRNA gene sequencing. Mycobiota was also studied by 26S rRNA gene metataxonomics, while metabolome was assessed through GC-MS analysis. Traditional culture-dependent methods showed the dominance of Candida diddensiae, Wickerhamomyces anomalus, Pichia membranifaciens and Aureobasidium pullulans, with differences in species distribution between batches, sampling time and type of sample (olives/brines). Amplicon-based sequencing confirmed the dominance of W. anomalus in batch 1 throughout the entire fermentation, while Cyteromyces nyonsensis and Aureobasidium spp. were most abundant in the fermentation in batch 2. Volatilome results were analyzed and correlated to the mycobiota data, confirming differences between fermentation stages. Given the high appreciation for this traditional food, this study helps elucidate the mycobiota associated to Taggiasca cv. table olives and its relationship with the quality of the final product.

Analysis of Fungal Diversity, Physicochemical Properties and Volatile Organic Compounds of Strong-Flavor Daqu from Seven Different Areas.

Strong-flavor Daqu, as a fermentation agent, plays a significant role in shaping the quality of strong-flavor baijius, and fungal species in Daqu are important factors affecting the quality of Daqu. Therefore, we selected strong-flavor Daqu from seven different origins to study the fungal composition and the effects of the fungal composition on the physicochemical properties and volatile organic compounds (VOCs). It was found that the fungal composition influences the physicochemical properties of Daqu. Specifically, there was a positive link between Rhizomucor, Rhizopus, Thermomyces, and liquefying activity and a positive correlation between Aspergillus and fermenting activity. Furthermore, the relationships between esterifying activity and Thermomyces, Rhizomucor, Aspergillus, Pichia, and Saccharomycopsis were found to be positive. The VOCs in Daqu were affected by Aspergillus, Issatchenkia, Pichia, and Thermoascus. Issatchenkia was significantly positively correlated with benzeneethanol as well as Aspergillus and pentadecanoic acid ethyl ester, ethyl myristate. Pichia and Thermoascus were significantly negatively correlated with benzaldehyde and 2-furaldehyde. This study deepens our understanding of the relationship between VOCs, the physicochemical properties with microbial communities, and reference significance for the production of better-quality strong-flavor Daqu.

Lactiplantibacillus plantarum A72, a Strain with Antioxidant Properties, Obtained through ARTP Mutagenesis, Affects Caenorhabditis elegans Anti-Aging.

This research endeavored to elucidate the antioxidant attributes of lactic acid bacteria, specifically their impact on anti-aging and lifespan augmentation in Caenorhabditis elegans. The study focused on Lactiplantibacillus plantarum A72, identified through ARTP mutagenesis for its potent antioxidant properties. In vitro analysis affirmed its free radical neutralizing capacity. In C. elegans, the strain not only extended the lifespan by 25.13% and amplified motility 2.52-fold, but also maintained reproductive capabilities. Remarkably, Lpb. plantarum A72 diminished reactive oxygen species (ROS) and malondialdehyde (MDA) levels in C. elegans by 34.86% and 69.52%, respectively, while concurrently enhancing its antioxidant enzyme activities. The strain also bolstered C. elegans survival rates by 46.33% and 57.78% under high temperature and H2O2 conditions, respectively. Transcriptomic scrutiny revealed that Lpb. plantarum A72 could retard C. elegans aging and extend lifespan by upregulating the sod-5 and hsp-16.1 genes and downregulating the fat-6 and lips-17 genes. These findings propose Lpb. plantarum A72 as a potential antioxidant and anti-aging lactic acid bacteria.

Production optimization of food functional factor ergothioneine in wild-type red yeast Rhodotorula mucilaginosa DL-X01.

BACKGROUND: Ergothioneine (EGT) is a high-value food functional factor that cannot be synthesized by humans and other vertebrates, and the low yield limits its application. RESULTS: In this study, the optimal fermentation temperature, fermentation time, initial pH, inoculum age, and inoculation ratio on EGT biosynthesis of Rhodotorula mucilaginosa DL-X01 were optimized. In addition, the effects of three key precursor substances - histidine, methionine, and cysteine - on fungal EGT synthesis were verified. The optimal conditions were further obtained by response surface optimization. The EGT yield of R. mucilaginosa DL-X01 under optimal fermentation conditions reached 64.48 ± 2.30 mg L-1 at shake flask fermentation level. Finally, the yield was increased to 339.08 ± 3.31 mg L-1 (intracellular) by fed-batch fermentation in a 5 L bioreactor. CONCLUSION: To the best of our knowledge, this is the highest EGT yield ever reported in non-recombinant strains. The fermentation strategy described in this study will promote the efficient biosynthesis of EGT in red yeast and its sustainable production in the food industry. © 2024 Society of Chemical Industry.

Mechanism of thermal oxidation into volatile compounds from (E)-4-decenal: A density functional theory study.

Unsaturated aliphatic aldehyde oxidation plays a significant role in the deep oxidation of fatty acids to produce volatile chemicals. Exposing the oxidation process of unsaturated aliphatic aldehydes is crucial to completely comprehend how food flavor forms. In this study, thermal desorption cryo-trapping in conjunction with gas chromatography-mass spectrometry was used to examine the volatile profile of (E)-4-decenal during heating, and 32 volatile compounds in all were detected and identified. Meanwhile, density functional theory (DFT) calculations were used, and 43 reactions were obtained in the 24 pathways, which were summarized into the peroxide reaction mechanism (ROOH), the peroxyl radical reaction mechanism (ROO·) and the alkoxy radical reaction mechanism (RO·). Moreover, the priority of these three oxidative mechanisms was the RO· mechanism > ROOH mechanism > ROO· mechanism. Furthermore, the DFT results and experimental results agreed well, and the oxidative mechanism of (E)-4-decenal was finally illuminated.

Inoculation of Yarrowia lipolytica promotes the growth of lactic acid bacteria, Debaryomyces udenii and the formation of ethyl esters in sour meat.

Yarrowia lipolytica N12 and A13 with high lipase activity obtained by mutagenesis were inoculated into sour meat, and their effects on physicochemical properties, microbial community succession, free amino acids, and volatile compounds of sour meat were investigated. Inoculation fermentation increased the contents of free amino acids observably, rapidly reduced pH, promoted the accumulation of total acids, decreased 2-thiobarbituric acid reactive substances (TBARS) values. In addition, the addition of Y. lipolytica might contribute to the growth of lactic acid bacteria, Candida spp., and Debaryomyces udenii, which play an important role in production of volatile compounds. It was shown that inoculation promoted the production of esters, aldehydes, and alcohols, especially ethyl esters, giving sour meat a better meat flavor. Besides, it was found that Y. lipolytica A13 had better fermenting property. Sample of A13 group had higher contents of ethyl esters, free amino acids and dominant microorganisms. The results may help to provide new strains for sour meat fermentation.

Daily Physical Activity Measured by Wearable Smartwatch for Patients Undergoing Transcatheter Aortic Valve Replacement: Insights From the SMART TAVR Study.

BACKGROUND: This study aims to evaluate limited data about daily physical activity patterns, influential factors, and their association with 1-year mortality or rehospitalization after transcatheter aortic valve replacement (TAVR) through smartwatches. METHODS: Consecutive severe aortic stenosis patients undergoing elective transfemoral TAVR in a Chinese tertiary hospital were enrolled from July 2021 to May 2022 and received a Huawei smartwatch at least 1 day before TAVR. The primary outcome was a composite of all-cause mortality or hospital readmission within 1 year. Linear mixed-effects models were applied to determine influential factors of daily step counts, and Cox proportional hazard regression models were to estimate the association between baseline step counts within 1 month since discharge and composite outcome from months 2 to 12. The dose-response association was assessed using restricted cubic spline curves. RESULTS: A total of 222 participants and 59 469 valid monitoring person-day records were included (mean age, 72.7 years; 61% women). Step counts increased rapidly within the first 2 months (P<0.001), followed by a slower increase for those without composite outcomes (P=0.029) and a gradual decrease for those who developed composite outcomes (P<0.001). In multivariate linear mixed models, a 1-m increase in baseline 6-minute walk test and a 1-month delay after discharge were associated with 4 (95% CI, 1-7) and 170 (95% CI, 145-194) additional step counts, respectively. In restricted cubic spline analysis, the hazard ratio declined progressively until ≈5000 steps per day, after which they leveled. Below 5000 steps, the adjusted hazard ratio of composite outcome associated with each 1000-step count increase was 0.67 (0.50-0.89; P=0.007). However, above 5000 steps, step counts were not significantly associated with the composite outcome (P=0.645), with a hazard ratio of 1.12 (0.70-1.79). CONCLUSIONS: Daily step counts rapidly increased within the first 2 months post-TAVR. Increased physical activity was associated with a lower risk of 1-year mortality or rehospitalization after TAVR for patients with daily step counts below 5000. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04454177.

Coupling the measures of pollution source control and water replenishment to improve water quality in the catchment scale of Qianshan River Basin.

With the development of the economy, the problem of urban black odorous water bodies has become increasingly significant, having a serious impact on the environment. As important means of remediating aquatic environments, pollution source control and water replenishment are of great significance in improving water quality. This study takes the Qianshan River Basin in Zhuhai City as its study area to simulate their effects on the improvement of water quality. A coupled model of water quantity and quality in Qianshan River Basin was constructed using MIKE11to analyze the water quality compliance rate, with sewage interception rates of 85%, 90%, and 95%, and to investigate the effect of pollution source control on the improvement of the aquatic environment. Using different sewage interception rates, the amount of water replenishment was calculated in order to meet water quality standards, the water replenishment scheme was determined via river-specific and time-specific methods, and the model was used to analyze the replenishment effect of the scheme. The results show that increasing the sewage interception rate can significantly improve the COD compliance rate, and improve the NH3-N and TP compliance rate; however, the enhancement effect is not sufficiently significant. When a sewage interception rate of 95% is implemented, there are still five rivers with a low NH3-N compliance rate, and six rivers with low a TP compliance rate. Comparing the water replenishment effect under different sewage interception rates of 85% and 95%, the water replenishment program alongside a sewage interception rate of 95% can effectively improve the aquatic environment and the water quality essentially meets the standard under different rainfall conditions; this demonstrates that the program presented herein can be used as the aquatic environment remediation program of choice for the Qianshan River Basin.

Density functional theory studies on the oleic acid thermal oxidation into volatile compounds.

Oleic acid oxidation is one of the main sources of food flavor compounds. Volatile profiling was investigated using thermal desorption cryo-trapping combined with gas chromatography-mass spectrometry to analyze the volatile composition of oleic acid oxidation. A total of 43 volatile compounds, including aldehydes (11), ketones (2), alcohols (5), furans (2), acids (8), ester (12) and alkane (3) were identified from oleic acid during heating. Then, density functional theory (DFT) was applied to analyze the oxidative mechanism of oleic acid during heating. A total of 30 reactions were obtained and grouped into the peroxide (ROOH), alkoxy radical (RO•), and peroxide radical (ROO•) pathways. The structures of intermediates, transition states (TS), and products in each reaction were also determined. Results show that the branch chemical reactions were the key reactions in different reaction pathway. Moreover, the reaction priority of the thermal oxidation reaction of oleic acid was the peroxide radical mechanism > the peroxide mechanism > the alkoxy radical mechanism.

Chemical Composition and Flavor Characteristics of Cider Fermented with Saccharomyces cerevisiae and Non-Saccharomyces cerevisiae.

Cider flavor has a very important impact on the quality. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) combined with gas chromatography-ion mobility spectrometry (GC-IMS) tested different kinds of non-Saccharomyces yeasts and Saccharomyces cerevisiae (S. cerevisiae) co-inoculated for the fermentation of cider to determine differences in aroma material, and the determination of odor activity value (OAV) is applied less frequently in research. Through Rhodotorula mucilaginosa, Debaryomyces hansenii, Zygosaccharomyces bailii, and Kluyveromyces Marxianus, four different strains of non-Saccharomyces yeast fermented cider, and it was found that, in both the chemical composition and flavor of material things, compared with monoculture-fermented cider using S. cerevisiae, all differences were significant. Co-inoculated fermentation significantly improved the flavor and taste of cider. As in the volatile compounds of OVA > 1, octanoic acid (Sc 633.88 µg/L, co-inoculation fermented group 955.49 µg/L) provides vegetable cheese fragrance and decanoic acid, ethyl ester (Sc 683.19 µg/L, co-inoculation fermented group 694.98 µg/L) a creamy fruity fragrance, etc., and the average content increased after co-inoculated fermentation. Phenylethyl alcohol, which can produce a rose scent, was relatively abundant in cider samples and varied greatly among the groups. Moreover, the contents of ethyl lactate and 1-butanol in the Sc+Rm (ciders fermented by S. cerevisiae and R. mucilaginosa) were the highest of all of the cider samples. Different types of non-Saccharomyces yeast produced cider with different flavor characteristics. This study demonstrates that different species of non-Saccharomyces yeast do have an important impact on the characteristics of cider and that co-inoculation with non-Saccharomyces yeast and S. cerevisiae for cider fermentation may be a strategy to improve the flavor of cider.

Inhibition Mechanism of Lactiplantibacillus plantarum on the Growth and Biogenic Amine Production in Morganella morganii.

Morganella morganii, a spoilage bacterium in fermented foods, produces harmful biogenic amines (BAs). Although Lactiplantibacillus plantarum is widely used to inhibit spoilage bacteria, the inhibition pattern and inhibition mechanism of M. morganii by Lpb. plantarum are not well studied. In this study, we analysed the effects of the addition of Lpb. plantarum cell-free supernatant (CFS) on the growth and BA accumulation of M. morganii and revealed the mechanisms of changes in different BAs by using RNA sequencing transcriptome analysis. The results showed that Lpb. plantarum CFS could significantly inhibit M. morganii BAs in a weak acid environment (pH 6), and the main changes were related to metabolism. Carbohydrate and energy metabolism were significantly down-regulated, indicating that Lpb. plantarum CFS inhibited the growth activity and decreased the BA content of M. morganii. In addition, the change in histamine content is also related to the metabolism of its precursor amino acids, the change in putrescine content may also be related to the decrease in precursor amino acid synthesis and amino acid transporter, and the decrease in cadaverine content may also be related to the decrease in the cadaverine transporter. The results of this study help to inhibit the accumulation of harmful metabolites in fermented foods.

The Screening and Isolation of Ethyl-Carbamate-Degrading Strains from Fermented Grains and Their Application in the Degradation of Ethyl Carbamate in Chinese Baijiu.

Ethyl carbamate (EC), a 2A carcinogen produced during the fermentation of foods and beverages, primarily occurs in distilled spirits. Currently, most studies focus on strategies for EC mitigation. In the present research, we aimed to screen strains that can degrade EC directly. Here, we report two Candida ethanolica strains (J1 and J116), isolated from fermented grains, which can reduce EC concentrations directly. These two yeasts were grown using EC as the sole carbon source, and they grew well on different carbon sources. Notably, after immobilization with chitosan, the two strains degraded EC in Chinese Baijiu by 42.27% and 27.91% in 24 h (from 253.03 ± 9.89 to 146.07 ± 1.67 and 182.42 ± 5.05 µg/L, respectively), which was better than the performance of the non-immobilized strains. Furthermore, the volatile organic compound content, investigated using gas chromatography-mass spectrometry, did not affect the main flavor substances in Chinese Baijiu. Thus, the yeasts J1 and J116 may be potentially used for the treatment and commercialization of Chinese Baijiu.

Construction and Optimization of Nonclassical Isoprenoid Biosynthetic Pathways in Yeast Peroxisomes for (+)-Valencene Production.

Isoprenoids are a kind of natural product with various activities, but their plant extraction suffers low concentration. The rapid development of synthetic biology offers a sustainable route for supply of high-value-added natural products by engineering microorganisms. However, the complexity of cellular metabolism makes engineering endogenous isoprenoid biosynthetic pathways with metabolic interaction difficult. Here, for the first time, we constructed and optimized three types of isoprenoid pathways (the Haloarchaea-type, Thermoplasma-type, and isoprenoid alcohol pathway) in yeast peroxisomes for the synthesis of sesquiterpene (+)-valencene. In yeast, the Haloarchaea-type MVA pathway is more effective than the classical MVA pathway. MVK and IPK were determined to be the rate-limiting steps of the Haloarchaea-type MVA pathway, and the production of 869 mg/L (+)-valencene under fed-batch fermentation in shake flasks was realized. This work expands isoprenoid synthesis in eukaryotes and provides a more efficient pathway for isoprenoid synthesis.

Deep exploration of lipid oxidation into flavor compounds: A density functional theory study on (E)-2-decenal thermal oxidative reaction.

Unsaturated fatty aldehydes are the main products of fatty acid oxidation, and could be further oxidized to form volatile compounds with shorter carbon chains. Therefore, studying the oxidation of unsaturated fatty aldehydes is an important way to reveal the mechanism of food flavor formation during heating. In this study, volatile profiling of (E)-2-decenal during heating was firstly investigated by using thermal-desorption cryo-trapping combined with gas chromatography-mass spectrometry (GC-MS). A total of 38 volatile compounds were detected. Then, twenty-one reactions in the heating process of (E)-2-decenal were obtained by using density functional theory (DFT) calculations, and grouped into three oxidation pathways, namely, peroxide pathway, peroxyl radical pathway and alkoxy radical pathway. Meanwhile, the priority of these three pathways was the alkoxy radical reaction pathway > peroxide pathway > peroxyl radical reaction pathway. Moreover, the calculated results agreed well with the experimental results.

Multi-omics analysis reveals the mechanism of torularhodin accumulation in the mutant Rhodosporidium toruloides A1-15 under nitrogen-limited conditions.

A carotenoid production strain Rhodosporidium toruloides NP11 and its mutant strain R. toruloides A1-15 were studied under chemostat nitrogen-limited cultivation. Multi-omics analysis (metabolomics, lipidomics and transcriptomics) was used to investigate the different mechanisms of torularhodin accumulation between NP11 and A1-15. The results showed that the carotenoid synthesis pathway was significantly enhanced in A1-15 compared to NP11 under nitrogen limitation, due to the significant increase of torularhodin. Under nitrogen-limited conditions, higher levels of ß-oxidation were present in A1-15 compared to those in NP11, which provided sufficient precursors for carotenoid synthesis. In addition, ROS stress accelerated the intracellular transport of iron ions, promoted the expression of CRTI and CRTY genes, and reduced the transcript levels of FNTB1 and FNTB2 in the bypass pathway, and these factors may be responsible for the regulation of high torularhodin production in A1-15. This study provided insights into the selective production of torularhodin.