Search Results (67)

Monascus pigments (MPs), natural food colorants produced by Monascus spp., have been traditionally used in China and Southeast Asia. Our prior work demonstrated that altered cell wall architecture in M. purpureus M9 significantly enhances pigment synthesis and secretion, although biosynthetic regulation under combined cell wall stress and acidic conditions remains unexplored. This study employed comparative transcriptomics to investigate coordinated regulation of MP production by pH stress and modified cell wall polysaccharides in wild-type (M9-WT) and UDP-galactopyranose mutase-deficient (M9-KO) strains at pH 5.0 and 3.0. At pH 5.0, MpglfA knockout enhanced MP secretion through cell wall restructuring involving differential expression total 67 genes (DEGs) of primary metabolism. Acidic stress (pH 3.0) significantly increased DEGs (168 up/643 down) in M9-KO versus M9-WT, inducing amino acid/fatty acid degradation pathways that generate MP precursors (acetyl-CoA/propionyl-CoA) and accelerating metabolic transition toward secondary metabolism. Concurrently, M9-KO adopted survival strategies featuring growth suppression and acid stress pathway activation to coordinate osmotic adaptation. Glucan synthase genes exhibited greater pH sensitivity than galactomannan-related genes, while MP biosynthetic genes were transcriptionally repressed in M9-KO under higher acidity. KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment and the series test of cluster confirmed that primary metabolic pathways, particularly nitrogen/carbon metabolism, critically regulate MP biosynthesis. Transcriptomic analysis under limited pH regimes revealed that antagonistic regulators ROX1 and SPT15 mediated pH-responsive transcriptional reprogramming, potentially regulating specific MP biosynthesis (e.g., monascus orange pigments). This work established theoretical foundations for manipulating cell wall composition to enhance MP production efficiency. Full article

Fermenting seaweed with koji fungi transforms its chemical composition, generating bioactive compounds absent in the raw material. We previously reported that the fungal fermentation of the edible red alga Pyropia yezoensis (Nori) produces betaine structural analogs (such as betaine, stachydrine, and carnitine), which are of particular interest because of their physiological roles and potential health benefits. Using metabolomic profiling, we compared non-fermented Nori with powders fermented by three industrially important fungi: Aspergillus luchuensis mut. kawachii (white koji fungus), Aspergillus oryzae (yellow koji fungus), and Monascus purpureus (red koji fungus). All fermentations enhanced the levels of betaine and carnitine, but stachydrine production was unique to the yellow koji fungus. Precursor patterns revealed distinct metabolic strategies: the yellow koji fungus exhibited an intermediate detectable choline oxidation route and strong proline methylation, the white koji fungus rapidly converted choline without intermediate accumulation, and the red koji fungus favored carnitine and proline but produced little stachydrine. Fermentation also shifted the methylation balance toward a state that supports methyl-dependent pathways. These findings reveal clear species-specific strategies for the production of betaine structural analogs, providing a mechanistic basis for understanding the metabolic divergence among koji fungi and guiding the targeted design of functional seaweed products. Full article

Monascus pigments (MPs) are the most valuable secondary metabolites of Monascus. To improve the production of MPs is of great importance to food processing. Currently, studies using rice bran as the substrate to produce MPs are rare. In this study, rice bran with different carbon sources and cellulase hydrolysis conditions were explored in Monascus purpureus M9 in this study. Through single-factor experiments and Box–Behnken response surface optimization, we demonstrated that mannitol supplementation combined with cellulase treatment of substrate significantly enhanced the yields of MPs. The optimal conditions (4.00% mannitol, cellulase hydrolysis at 60 °C for 2 h) achieved a maximum color value of 3538 U/g. Furthermore, comparative evaluation under different culture conditions, including only rice bran (RB), cellulase hydrolysis of rice bran (Cel), rice bran supplemented with mannitol (Man), mannitol supplementation combined with cellulase pretreatment of substrate (Opti), and only rice (Rice), confirmed the effectiveness of the optimized treatment. The color value of the Opti group was 27.95 times more than that of the RB group and reached 80.96% of the counterpart of the Rice group. The Opti group also significantly enhanced the yields of two orange pigments (Monascorubrin and Rubropunctatin), induced more sexual spore formation, and exhibited the maximum biomass and colony diameter among different groups. The hyphae of the Man and Opti groups were full, intact, and tubular. The citrinin content in the Opti group was under the limit standard of China. The data provides a theoretical basis reference for improving the yields of MPs with RB as the substrate. Full article

Monascus purpureus is a filamentous fungus known for producing pharmaceutically valuable secondary metabolites, including azaphilone pigments and lovastatin. Lovastatin is an HMG-CoA reductase inhibitor widely used to manage hypercholesterolaemia, while Monascus pigments serve as natural colourants with antioxidant and antimicrobial properties. This study evaluated the impact of quorum-sensing molecules (QSMs)—tyrosol (0.3 mM), farnesol (0.2 mM) and linoleic acid (0.4 mM)—on pigment and lovastatin yields in shake flasks and 2.5 L stirred-tank bioreactors. QSMs were introduced 48 h post-inoculation in shake flasks and 24 h in bioreactors. All QSMs increased yellow (OD₄₀₀), orange (OD₄₇₀), and red (OD₅₁₀) pigments and lovastatin concentration relative to the control, with scale-up further enhancing yields. Farnesol produced the most pronounced effect: in flasks, OD₄₀₀ 7.10 (1.86-fold), OD₄₇₀ 8.00 (2.12-fold), OD₅₁₀ 7.80 (2.08-fold), and 74.6 mg/L lovastatin (2.05-fold); in bioreactors, OD₄₀₀ 11.9 (2.06-fold), OD₄₇₀ 15.1 (2.71-fold), OD₅₁₀ 13.7 (2.47-fold), and 97.2 mg/L lovastatin (2.48-fold). This was followed by tyrosol treatment and then linoleic acid. These findings demonstrate that QSMs—particularly farnesol—significantly (p < 0.01) stimulate pigment and lovastatin biosynthesis in M. purpureus. Quorum sensing modulation represents a promising, scalable strategy to optimise fungal fermentation for industrial metabolite production. Full article

Monascus purpureus is a filamentous fungus renowned for producing bioactive secondary metabolites, including lovastatin and azaphilone pigments. Lovastatin is valued for its cholesterol-lowering properties and cardiovascular benefits, while Monascus pigments exhibit anti-cancer, anti-inflammatory, and antimicrobial activities, underscoring their pharmaceutical and biotechnological relevance. This study evaluated the impact of carbohydrate-derived elicitors—mannan oligosaccharides, oligoguluronate, and oligomannuronate—on the enhancement of pigment and lovastatin production in M. purpureus C322 under submerged fermentation. Elicitors were added at 48 h in shake flasks and 24 h in 2.5 L stirred-tank fermenters. All treatments increased the production of yellow, orange, and red pigments and lovastatin compared to the control, with higher titres upon scale-up. OG led to the highest orange pigment yield (1.2 AU/g CDW in flasks; 1.67 AU/g CDW in fermenters), representing 2.3- and 3.0-fold increases. OM yielded the highest yellow and red pigments (1.24 and 1.35 AU/g CDW in flasks; 1.58 and 1.80 AU/g CDW in fermenters) and the highest lovastatin levels (10.46 and 12.6 mg/g CDW), corresponding to 2.03–3.03-fold improvements. These results highlight the potential of carbohydrate elicitors to stimulate metabolite biosynthesis and facilitate scalable optimisation of fungal fermentation. Full article

Most wheat bran in China is used as animal feed due to its coarse taste. However, fermentation can degrade cellulose in wheat bran, improving its taste and flavor. The effects of co-fermentation with Lactiplantibacillus plantarum and Monascus purpureus on wheat bran remain unclear. In this study, we evaluated soluble pentosan, total phenol content, and antioxidant activity in co-fermented wheat bran. Following treatment, the soluble pentosan content was 6.03-fold higher than in raw bran. The total phenol content increased by 5.74-fold, and antioxidant activity was enhanced as well. The flavor profile of wheat bran co-fermented with L. plantarum and M. purpureus changed significantly, with alcohols and pyrazines increasing by 3- to 20-fold and aldehydes decreasing by 52.76%, resulting in a fruity, sweet, and nutty aroma. This study supports the comprehensive utilization of wheat bran and provides novel insights into improving its functionality and quality. Full article

Background: This study investigates the cytotoxicity of microbial polyketides biosynthesized by Monascus species through both in silico and in vitro approaches. Methods: Six main know Monascus-derived polyketides were analysed in silico an an vitro. Results: In silico tests reveal that the main derived compounds exhibit lipophilic properties, indicating their potential suitability as active ingredients in dermato-cosmetic formulations. In silico tests revealed significant flexibility and high degrees of unsaturation for some Monascus-derived polyketides, suggesting a broad interaction potential and a propensity for chemical instability. In silico permeability tests indicated low epidermal penetration. Cytotoxicity assays conducted in vitro on a HaCaT cell line revealed varying levels of cytotoxicity among the three classes of fungal polyketides. Yellow polyketides derived from Monascus purpureus and Monascus ruber exhibited moderate cytotoxicity, while orange polyketides derived from the same strains showed low cytotoxicity. Red, orange, and yellow polyketides derived from a high-productive Monascus sp. genus showed low or negligible cytotoxicity. After 48 h of exposure, the cytotoxic profiles of all Monascus polyketides remained relatively stable. The IC₅₀ values obtained through linear or nonlinear models supplied by EXCEL MS Office or for the Systat programme indicated moderate-to-low cytotoxicity for polyketides derived from Monascus ruber and Monascus purpureus. The bioproducts derived from high-productive Monascus sp. exhibited weak or negligible cytotoxicity. Conclusions: The results obtained suggest that the Monascus-derived polyketides possess promising properties for therapeutic and cosmetic applications, but their chemical stability must be considered in the case of dermatological formulations. Full article

Persimmon waste, accounting for up to 30% of annual harvests, presents economic and environmental challenges due to limited processing options. This study introduces a staged fermentation process to transform persimmon into high-quality wine using a Saccharomyces cerevisiae consortium (EC/Aq/F33 = 4/4/7) followed by Monascus purpureus. The process decouples ethanol production and esterification to avoid nutrient competition: an 8-day yeast phase (21.11 °Brix, 0.29 g kg⁻¹ yeast, 19.90 °C, pH 3.8) yields 12.12% (v/v) ethanol, followed by M. purpureus (1.56% inoculation, 22.6 °C, pH 4.0) on day 8 for 10 days, producing 3.56 g L⁻¹ esters. This results in 32 volatile compounds (e.g., phenethyl acetate), achieving a sensory score of 90.9/100–43% higher in aromatic diversity than single-strain fermentation. By shortening fermentation time by 40% compared with traditional methods (>25 days) and enhancing flavor complexity, this scalable approach offers a sustainable solution for upcycling persimmon and other tannin-rich perishables, supporting eco-friendly food production. Full article

With increasing research, the nutritional value of oats is gaining recognition. Fermentation is an emerging biotransformation pattern that changes the nutritional structure of whole grains. Currently, research on whole-grain fermentation is relatively focused on phenolic compounds and their antioxidants, but less attention has been given to avenanthramides (Avns) and the glycemic index (GI) in fermented oats. In this study, oats were subjected to solid-state fermentation (SSF) by Monascus purpureus for 21 days, and samples were taken at different time points. Changes in the contents of nutrients, phytochemicals, and antinutritional factors were analyzed using one-way ANOVA. Additionally, a simulated in vitro digestion experiment was conducted to assess the estimated glycemic index (eGI) of SSF oats. The results revealed that the nutritional structure of oats was changed by SSF, and the Avns content significantly increased, with 3.2 times more Avns in SSF oats than in unfermented oats, including 3.05, 3.09, 3.09, and 3.7 times more Avn A, Avn B, Avn C, and Avn D, respectively, and the eGI was reduced from 40.22 to 39.97 with increasing fermentation time. In general, SSF with Monascus purpureus has improved nutritional value, significantly increased the content of active ingredients, and reduced the level of eGI and two antinutritional factors (phytate and oxalate), which provides an effective way to improve the nutritional and digestive characteristics of oats. Full article

Glycine betaine (GB) serves as both a methyl donor and osmoprotectant in microorganisms, facilitating growth and enhancing metabolic product yields. While the polyketide metabolites from Monascus purpureus, such as Monascus pigments (MPs) and monacolin K (MK), have been extensively studied, the effects of GB on their production and the underlying molecular mechanisms remain insufficiently explored. In this study, various concentrations of GB were added to Monascus purpureus M1 cultures, followed by RNA sequencing, RT-qPCR, differential gene expression analysis, and functional enrichment to investigate the regulatory impact of GB on polyketide metabolism. Protein–protein interaction network analysis identified key upregulated genes, including RPS15, RPS14, RPS5, NDK1, EGD2, and ATP9, particularly during the later growth phases. GB significantly upregulated genes involved in stress response, secondary metabolism, and polyketide biosynthesis. Scanning electron microscopy, HPLC, and UV-Vis spectrophotometry further confirmed that GB promoted both strain growth and polyketide production, with red pigment and MK production increasing by 120.08% and 93.4%, respectively. These results indicate that GB enhances growth and polyketide metabolism in Monascus purpureus by functioning as both a methyl donor and osmoprotectant, offering new insights into optimizing microbial polyketide production and revealing gene regulatory mechanisms by GB in Monascus purpureus. Full article

Red yeast rice is a nutraceutical fermented product used worldwide for the symptomatic relief of dyslipidemia and cardiovascular disease. However, the fermentation-induced lipid transformation from rice to red yeast rice remains unclear. Herein, an ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry method was developed for the comprehensive lipid analysis during fermentation. A total of 246 lipids fall in 21 subclasses were annotated in rice and red yeast rice, including 37 lysophospholipids, 14 phospholipids, 29 diglycerides, 114 triglycerides and fatty acid (15 species), ceramide (12 species), hexosylceramide (3 species), sitosterol ester (2 species), monogalactosyldiacylglycerol (2 species), digalactosyldiacylglycerol (2 species), monogalactosylmonoacylglycerol (8 species), digalactosylmonoacylglycerol (5 species), coenzyme Q (1 species), acyl hexosyl campesterol ester (1 species), and acylcarnitine (1 species). Results showed that lipid profiles changed, and new lipid species emerged. Notably, 18 medium- and long-chain triacylglycerols and triacylglycerols with short-chains were tentatively identified. These triacylglycerols also show the effects of body fat accumulation reduction, and hypolipidemic and hypoglycemic activities. Furthermore, lipid species that were profoundly changed were quantified, and the dynamic changes were investigated. This study clarified the molecular species and compositional changes in fermented rice from lipid aspect. Full article

Antimicrobial resistance (AMR) poses a critical global health threat, driving the search for alternative treatments to conventional antibiotics. In this study, the antibacterial properties of honeybee venom (BV) and fungal Monascus purpureus red dye (RD) were evaluated against three multidrug-resistant bacterial pathogens. Extracts of BV and RD exhibited dose-dependent antibacterial activity against the three tested bacteria, with their strongest effectiveness against S. aureus (minimum inhibitory concentrations [MIC] = 3.18 and 6.315 μg·mL⁻¹, respectively). Although the three bacterial strains were resistant to the antibiotic ampicillin-sulbactam (10/10 µg), both extracts exhibited superior antibacterial activity against the three bacterial strains compared to five standard antibiotics, especially RD extract, which produced the largest inhibition zone (20 ± 0.20 mm) against S. aureus. The larger inhibition zones against S. aureus suggest its high sensitivity, whereas E. coli and E. faecalis exhibited smaller inhibition zones, indicating less sensitivity to BV and RD extracts. Differences in the inhibition zones suggest the variations in antimicrobial activity between the two extracts and their strain-specific effectiveness. Scanning electron microscopy (SEM) revealed that BV and RD extracts disrupted the bacterial plasma membrane, suggesting that the bioactive compounds penetrate the bacterial cell wall and alter its integrity. Furthermore, GC–MS-based analysis revealed that the chemical composition of BV and RD extracts exhibited highly diverse structures, including complex polycyclic systems, porphyrins, steroids, and esters. For instance, 42 metabolites were identified in the BV extract, which mainly were organic and metal–organic compounds; however, only 23 molecules were identified in RD extract, which mainly were fatty acids and their derivatives. The diversity in the chemical compositions of both extracts highlights their potential applications in pharmaceuticals, materials, and biochemistry fields. Collectively, these findings indicate that honeybee venom and the red dye from M. purpureus have promising antibacterial properties and warrant further investigation as potential alternatives to conventional antibiotics. Further multi-ligand docking-based virtual screening studies are required to identify the most promising detected metabolite(s) within both BV and RD extracts. Full article

Jiuqu (starter) makes an important contribution to the formation of the flavor characteristics of Hongqu rice wine (HQW). Gutian Qu (GTQ) and Wuyi Qu (WYQ) are two kinds of Jiuqu commonly used in HQW brewing, but the comparison of the two kinds of HQW is still insufficient at present. The objective of this study was to compare the dynamic changes of amino acids (AAs), higher alcohols (HAs), bioamines (BAs), volatile flavor compounds (VFCs), and microbial communities in HQW fermentation, with GTQ and WYQ as starter. This study used an automatic amino acid analyzer, GC, HPLC, and GC-MS to detect AAs, HAs, Bas, and VFCs during fermentation; metagenomic sequencing technology was used to elucidate the microbial community and its functional characteristics. The results showed that the contents of AAs and HAs in HQW brewed with WYQ (WYW) were significantly higher than those in HQW brewed with GTQ (GTW). On the contrary, the majority of BAs in GTW were significantly higher than those in WYW. The composition of VFCs in WYW and GTW were obviously different, as most of the VFCs were notably enriched in WYW, while ethyl caproate, isoamyl acetate, ethyl heptanoate, ethyl nonanoate, 1-decanol, citronellol, phenethyl acetate, and hexanoic acid were more abundant in GTW. Burkholderia gladioli, Pantoea dispersa, Weissella cibaria, Monascus purpureus, and Saccharomyces cerevisiae were the predominant microbial populations in GTW brewing at the species level, while Sphingomonas sp., Kosakonia cowanii, Enterobacter asburiae, Leuconostoc lactis, Aspergillus niger, and Saccharomyces cerevisiae were the dominant microbial species in WYW brewing. The abundance of functional genes involved in BAs biosynthesis were much higher in GTW brewing, while the abundance of functional genes related to the metabolism of characteristic VFCs were much higher in WYW brewing. Collectively, these findings provided evidence for elucidating the effects of Jiuqu and microbial communities on HQW flavor quality, and laid a solid foundation for the improvement of HQW flavor quality. Full article

The risk of cardiovascular disease (CVD) is approximately doubled in subjects with hypercholesterolemia compared to those with normal blood cholesterol levels. Monacolin K (MK), the main active substance in rice fermented by the Monascus purpureus, acts on cholesterol metabolism. Rice also contains other bioactive compounds such as γ-oryzanol (OZ) and γ-aminobutyric acid (GABA). In a randomized, placebo-controlled, double-blind trial, the efficacy and tolerability of a food supplement (FS) based on an ingredient standardized to contain monacolins (4.5%), OZ, and GABA were evaluated in subjects with mild dyslipidemia. For the duration of the trial, enrolled subjects (n = 44, each group) received the FS or placebo and were instructed to use an isocaloric diet. Compared to the placebo group, after a 3 months of the FS, the mean low-density lipoprotein cholesterol and mean TC values were reduced by 19.3 and 8.3%, respectively, while the mean high-density lipoprotein cholesterol value increased by 29.3%. On average, the subjects shifted from very high to moderate CVD risk. Glucose metabolism and hepatic and renal parameters did not change after the treatment and no adverse events were reported. Guidelines to handle hypercholesterolemia with food supplements in specific clinical settings are needed to better manage mild dyslipidemia. Full article

Beta-glucan (β-glucan), a naturally occurring complex polysaccharide, has drawn attention for its diverse health benefits, including immune system modulation. β-glucan was extracted from two fungi, Monascus purpureus (Mp) and Monascus kaoliang (Mk), cultured in Saccharina japonica via submerged fermentation. The yield, solubility, total sugar, reducing sugar, protein content, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM), in vitro free radical scavenging activity, and cytotoxicity were analyzed. A significant yield of β-glucans, with the contents of 51.30 ± 1.54% in Mp and 44.24 ± 1.18% in Mk was observed on a dry weight basis. Water solubility slightly varied, measuring 36.25 ± 1.14% in Mp and 31.25 ± 0.94% in Mk. Total sugar and reducing sugar content in Mp and Mk derived β-glucans were 114.75 ± 2.54 mg/g and 100.25 ± 1.86 mg/g, 7.38 ± 0.78 mg/g, and 8.39 ± 0.46 mg/g, respectively. FTIR spectra resembled the standard, and TGA confirmed heat stability. XRD patterns indicated that the extracted β-glucans, including the standard one, showed the most prominent diffraction peaks in the lower 2θ range, suggesting similar crystalline phases; however, they differed in crystallinity and degree of amorphous content. SEM images displayed characteristic rough and fibrous shapes and surfaces for extracted β-glucans but it was uniform and of a regular shape in the standard sample. The isolated β-glucans exhibited in vitro free radical scavenging and no cytotoxicity was observed in the MTS assay. Therefore, utilizing S. japonica as a substrate in the fermentation process by Monascus spp. presents a unique opportunity in the production and utilization of β-glucans. Full article