Monascus Purpureus Research Articles

Enhancement of bioactive compounds, antioxidant capacity, and inhibitory effects on mushroom tyrosinase, α-glucosidase, and nitric oxide production in sorghum (Sorghum bicolor L.) via solid-state fermentation with Monascus purpureus

Enhancement of bioactive compounds, antioxidant capacity, and inhibitory effects on mushroom tyrosinase, α-glucosidase, and nitric oxide production in sorghum (Sorghum bicolor L.) via solid-state fermentation with Monascus purpureus

Quality Control and Safety Assessment of Online-Purchased Food Supplements Containing Red Yeast Rice (RYR).

Dietary supplements containing red yeast rice (RYR), a fermentation product of the fungus Monascus purpureus grown on white rice, remain popular in Europe as proclaimed cholesterol-lowering aids. The cholesterol-lowering effects are due to the occurrence of monacolin K, which is often present as a mixture of monacolin K lactone (MK) and as monacolin K hydroxy acid (MKA). MK is structurally similar to the cholesterol-lowering medicine lovastatin. Recently, due to safety concerns linked to the use of statins, the European Commission prohibited RYR supplements with a maximum serving exceeding 3 mg of total monacolins per day. Moreover, the amount of the mycotoxin citrinin, potentially produced by M. purpureus, was also reduced to 100 µg/kg. Evidently, manufacturers that offer their products on the European market, including the online market, must also be compliant with these limits in order to guarantee the safety of their products. Therefore, thirty-five different RYR supplements, purchased from an EU-bound e-commerce platform or from registered online pharmacies, were screened for their compliance to the European legislation for citrinin content and the amount of total monacolin K. This was conducted by means of a newly developed LC-MS/MS methodology that was validated according to ISO 17025. Moreover, these supplements were also screened for possible adulteration and any contamination by micro-organisms and/or mycotoxins. It was found that at least four of the thirty-five RYR supplements (≈11%) might have reason for concern for the safety of the consumer either due to high total monacolin K concentrations exceeding the European predefined limits for total monacolins or severe bacterial contamination. Moreover, three samples (≈9%) were likely adulterated, and the labeling of six of the seventeen samples (≈35%) originating from an EU-based e-commerce platform was not compliant, as either the mandatory warning was missing or incomplete or the total amount of monacolins was not mentioned.

Comparative Cytotoxicity Evaluation of Heat-Assisted vs Cold Water Extractions of Six Medicinal Fungi against Breast and Lung Cancer Cells.

Preparation of medicinal fungi for experimental purposes usually involves the extraction and determination of the quality and quantity of bioactive compounds prior to the biological experiment. Water, a common polar solvent, is usually used for traditional preparations for consumption. The application of high temperatures during water extraction can affect the chemical composition and functional properties of the extracts. Therefore, the aim of this study is to compare the differences in composition between extracts obtained with heat-assisted and cold water extractions of six selected species of fungi (Lignosus rhinocerus, Ophiocordyceps sinensis, Inonotus obliquus, Antrodia camphorata, Phellinus linteus and Monascus purpureus) and their cytotoxicity against human lung and breast cancer cells. The extracts obtained with heat-assisted and cold water extraction of six species of fungi were analysed to determine their protein, carbohydrate and phenolic contents. Their cytotoxicity was tested against lung (A549) and breast (MCF-7 and MDA-MB-231) cancer cell lines. The most potent extract was further separated into its protein and non-protein fractions to determine their respective cytotoxicity. The cytotoxicity of the different extracts obtained with heat-assisted and cold water extraction varied. Comparing the two extractions, the cold water extraction resulted in a significantly higher yield of proteins (except M. purpureus) and phenolic compounds (except A. camphorata), while the extracts of I. obliquus and M. purpureus obtained with heat-assisted extraction had a significantly higher carbohydrate mass fraction. Notably, the cold water extract of I. obliquus showed cytotoxicity (IC50=(701±35) µg/mL), which was one of the highest of the extracts tested against A549 cells. The cold water extract of I. obliquus was selected for further studies. Our results showed that cold water extracts generally have higher cytotoxicity against selected human cancer cell lines, with the exception of O. sinensis and A. camphorata extracts. This study reports the advantage of cold water extracts of fungi over those obtained with heat-assisted extraction in terms of cytotoxicity against human cancer cell lines and emphasises the role of extraction conditions, particularly heat, in influencing chemical composition and cytotoxic effects.

Characterization and antioxidant properties of three exopolysaccharides produced by the Cyclocarya paliurus endophytic fungus

In recent years, the considerable potential of endophytic bacteria and fungi as prolific producers of exopolysaccharides (EPSs) have attracted interest. In this study, 56 endophytes were isolated from Cyclocarya paliurus, and the secondary metabolites of EPSs were extracted from Monascus purpureus, Penicillium citrinum and Aspergillus versicolor, screened, and named MPE, PCE and AVE, respectively. In this work, the physicochemical properties and antioxidant activities of three EPSs, their cell proliferation activity on IEC-6 and RAW264.7 were investigated. The three EPSs were mainly composed of neutral sugar and differ in microstructure. However, MPE had a loose structure, and PCE exhibited a dense and sheet-like structure. In addition, the three EPSs performed ordinary antioxidant activity in vitro but showed excellent cell proliferation activity on IEC-6 and RAW264.7. The cell proliferation activity of PCE was 1.4-fold that of the controls at a concentration of 800 μg/mL on IEC-6, and MPE exhibited 1.3-fold increase on RAW264.7. This study provided scientific evidence and insights into the application of endophytes as a novel plant resource possessing huge application potential.

Unlocking fungal quorum sensing: Oxylipins and yeast interactions enhance secondary metabolism in monascus

Exploring the symbiotic potential between fungal and yeast species, this study investigates the co-cultivation dynamics of Monascus, a prolific producer of pharmacologically relevant secondary metabolites, and Wickerhamomyce anomalous. The collaborative interaction between these microorganisms catalyzed a substantial elevation in the biosynthesis of secondary metabolites, prominently Monacolin K and natural pigments. Central to our discoveries was the identification and enhanced production of oxylipins (13S-hydroxyoctadecadienoic acid，13S-HODE), putative quorum-sensing molecules, within the co-culture environment. Augmentation with exogenous oxylipins not only boosted Monacolin K production by over half but also mirrored morphological adaptations in Monascus, affecting both spores and mycelial structures. This augmentation was paralleled by a significant upregulation in the transcriptional activity of genes integral to the Monacolin K biosynthetic pathway, as well as genes implicated in pigment and spore formation. Through elucidating the interconnected roles of quorum sensing, G-protein-coupled receptors, and the G-protein-mediate signaling pathway, this study provides a comprehensive view of the molecular underpinnings facilitating these metabolic enhancements. Collectively, our findings illuminate the profound influence of Wickerhamomyces anomalous co-culture on Monascus purpureus, advocating for oxylipins as a pivotal quorum-sensing mechanism driving the observed symbiotic benefits.

Taurine-mediated gene transcription and cell membrane permeability reinforced co-production of bioethanol and Monascus azaphilone pigments for a newly isolated Monascus purpureus

BackgroundTaurine, a semi-essential micronutrient, could be utilized as a sulfur source for some bacteria; however, little is known about its effect on the accumulation of fermentation products. Here, it investigated the effect of taurine on co-production of bioethanol and Monascus azaphilone pigments (MonAzPs) for a fungus.ResultsA newly isolated fungus of 98.92% identity with Monascus purpureus co-produced 23.43 g/L bioethanol and 66.12, 78.01 and 62.37 U/mL red, yellow and orange MonAzPs for 3 d in synthetic medium (SM). Taurine enhanced bioethanol titer, ethanol productivity and ethanol yield at the maximum by 1.56, 1.58 and 1.60 times than those of the control in corn stover hydrolysates (CSH), and red, yellow and orange MonAzPs were raised by 1.24, 1.26 and 1.29 times, respectively. Taurine was consumed extremely small quantities for M. purpureus and its promotional effect was not universal for the other two biorefinery fermenting strains. Taurine intensified the gene transcription of glycolysis (glucokinase, phosphoglycerate mutase, enolase and alcohol dehydrogenase) and MonAzPs biosynthesis (serine hydrolases, C-11-ketoreductase, FAD-dependent monooxygenase, 4-O-acyltransferase, deacetylase, NAD(P)H-dependent oxidoredutase, FAD-dependent oxidoredutase, enoyl reductase and fatty acid synthase) through de novo RNA-Seq assays. Furthermore, taurine improved cell membrane permeability through changing cell membrane structure by microscopic imaging assays.ConclusionsTaurine reinforced co-production of bioethanol and MonAzPs by increasing gene transcription level and cell membrane permeability for M. purpureus. This work would offer an innovative, efficient and taurine-based co-production system for mass accumulation of the value-added biofuels and biochemicals from lignocellulosic biomass.

Correlation of oxygen consumption with growth and red pigment production of Monascus purpureus in solid state fermentation of rice

Since aeration has a crucial role in mass and heat transfer during solid-state fermentation (SSF), the aim of the present work was to find out how it related to biomass and red pigment production of Monascus purpureus TISTR3615 during SSF. The fungal consumption of oxygen, one of the air's constituents important for fungal metabolism, was used to explain the relationship between the aeration rate, the fungal growth, and the red pigment production during the SSF of rice. Findings showed that at increased aeration rates, the fungus absorbed more oxygen, which boosted fungal growth but decreased red pigment production. Conversely, red pigment production increased when the fungus' oxygen consumption decreased. Regression equations with an acceptable R2 were used to explain the relationship between M. purpureus' red pigment production and its oxygen consumption and aeration rate. The ideal oxygen concentration for increasing M. purpureus' capacity to produce red pigment was 0.0685 mmol/day/g of dry biomass, which produced red pigment at around 2,897 AU500nm/g of dry biomass. However, the optimal oxygen consumption of the fungus for overall red pigment production (including growth impact) was 1.390 mmol/day/g of dry biomass, which produced red pigment at around 2,787 AU500nm/g of dry fermented rice. The results of the present work could potentially be utilised in developing M. purpureus' red pigment production approach.

Yellow pigment fraction from Monascus-fermented durian seed: thermal stability and bioactivities

Angkak is a functional product made by fermenting rice with Monascus purpureus. Studies have shown that agro-industrial by-products such as durian seeds are able to support Monascus growth, thus the potential of producing Monascus-fermented products with similar functional activities as angkak. Utilization of durian seeds to produce Monascus-fermented durian seed (MFDS) would improve durian production sustainability. Monascus yellow pigment (MYP) fraction was separated from MFDS and evaluated for its thermal stability by time (30 and 60 mins) and temperature treatments (40℃, 60℃, 80℃ and 100℃), antioxidant activity with 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity assay, and anti-diabetes activities by measuring α-glucosidase inhibition activity. MYP showed increasing stability when treated with increasing incubation temperature, ranging from 90.87±0.35% to 96.33±0.00% (p < 0.05). MYP reached the highest stability when incubated at 100℃ for 60 mins. The antioxidant activity of MYP was detected to be 51.84±0.17%. MYP showed anti-diabetes activity ranging from -0.72±0.27% (10 μg/mL) to 29.40±4.27% (100 μg/mL). There was an increase in α-glucosidase inhibition activity along with increasing MYP concentration. Monascus yellow pigments extracted from Monascus-fermented durian seed have the potential to be used as a functional ingredient in the food industry.

Purification, characterisation and immobilisation of a protease‐resistant α‐galactosidase from Monascus purpureus and its application in removal of raffinose family oligosaccharides

SummaryIn this study, an α‐galactosidase (MPG) was produced by submerged fermentation from Monascus purpureus, a food‐grade fungus used for making red yeast rice. MPG was purified from intracellular extract which showed a subunit molecular mass of 95 kDa. MPG was optimally active at pH 4.0 and 50 °C and was stable between pH 3.5–8.0 and at temperatures up to 50 °C. The enzyme retained its activity in the presence of most of the metal ions except Cu2+ and Fe2+. MPG exhibited remarkable resistance to the proteases, pepsin, trypsin and proteinase K as well as to the sugars, galactose and sucrose. Moreover, it retained complete activity under simulated gastric conditions. The enzyme displayed specificity for the substrates, melibiose, raffinose and stachyose and was able to hydrolyze these oligosaccharides. It was effective in the removal of non‐digestible raffinose family oligosaccharides (RFOs) from soybeans, chickpeas and kidney beans. MPG was immobilised onto chitosan and the immobilised enzyme (iMPG) displayed higher optimal temperature (60 °C), better thermostability and substrate specificity as compared to MPG. iMPG was also capable of hydrolyzing RFOs in chickpeas and could be efficiently reused six times. In view of their superior properties, MPG and iMPG may have great prospects in the food and feed industries for the removal of RFOs from soy and other legumes.

Monascus purpureus M-32 fermented soybean meal improves the growth, immunity parameters, intestinal morphology, disease resistance, intestinal microbiota and metabolome in Pacific white shrimp (Litopenaeus vannamei)

This study was conducted to evaluate the effects of Monascus purpureus M-32 fermented soybean meal (MFSM) on growth, immunity, intestinal morphology, intestinal microbiota, and intestinal metabolome of Pacific white shrimp (Litopenaeus vannamei). Four groups of diets were formulated, including control group (30% fish meal and 30% soybean meal [SBM] included in the basal diet) and three experimental groups which MFSM replaced 20% (MFSM20), 40% (MFSM40), and 60% (MFSM60) of SBM in control group, respectively. Results showed that the soluble proteins larger than 49 kDa in MFSM were almost completely degraded. Meanwhile, the crude protein, acid-soluble protein, and amino acid in MFSM were increased. The results of shrimp culture experiment showed that the replacement of SBM with MFSM decreased FCR (P < 0.001) and content of malondialdehyde (P = 0.007) in the experimental groups, and increased weight gain rate (P = 0.006), specific growth rate (P = 0.002), survival rate (P = 0.005), intestinal villus height (P < 0.001), myenteric thickness (P = 0.002), the activities of superoxide dismutase (P = 0.002), and lysozyme (P = 0.006) in experimental groups, as well as increased content of calcium (Ca2+) and phosphorus (PO43−) in blood and muscle, and enhanced resistance to Vibrio parahaemolyticus infection. The gut microbiota of MFSM groups was significantly different from that of the control group, and the abundance of Actinobacteria and Verrucomicrobia increased significantly in the MFSM60 group, whereas Proteobacteria and Firmicutes decreased. Compared with the control group, there were significant changes in the levels of several intestinal metabolites in the MFSM60 group, including leukotriene C5, prostaglandin A1, taurochenodeoxycholic acid, carnosine, and itaconic acid. The fermentation of SBM by the strain M. purpureus M-32 has the potential to enhance the nutritional quality of SBM, promote the growth of L. vannamei, boost immune response, improve intestinal morphology and microbiota composition, as well as influence intestinal metabolites.

Improving the Quality and Flavor of Monascus Rice Wine Brewed by Pure Culture Using the Addition of Trichosanthis Fructus

Trichosanthis Fructus (TrF) is an edible medicinal fruit with a sweet taste and pleasant flavor. In this study, different concentrations of TrF were added into the media to brew Monascus rice wine using a pure culture method, and the physicochemical properties, volatile compounds, antioxidant activity, and sensory quality of the brewed samples were characterized. In addition, the effect of TrF on the growth and metabolism of Monascus purpureus and Saccharomyces cerevisiae was investigated. The results show that addition of TrF reduces the growth and metabolism of M. purpureus and S. cerevisiae in a dose-dependent manner, but also enriches the flavor components, in addition to increasing the total phenolic and flavonoid contents, and antioxidant activity of rice wine. Combined with the results of sensory evaluation, we find that 15% TrF is optimal for improving the flavor of Monascus rice wine. The results from this study can serve as a basis for improving the quality and flavor of rice wine brewed using pure strain culture.

An Exopolysaccharide from Genistein-Stimulated Monascus Purpureus: Structural Characterization and Protective Effects against DSS-Induced Intestinal Barrier Injury Associated with the Gut Microbiota-Modulated Short-Chain Fatty Acid-TLR4/MAPK/NF-κB Cascade Response.

Inflammatory bowel disease is a major health problem that can lead to prolonged damage to the digestive system. This study investigated the effects of an exopolysaccharide from genistein-stimulated Monascus purpureus (G-EMP) in a mouse model of colitis to clarify its molecular mechanisms and identified its structures. G-EMP (Mw = 56.4 kDa) was primarily consisted of → 4)-α-D-Galp-(1 →, → 2,6)-α-D-Glcp-(1→ and →2)-β-D-Manp-(1 → , with one of the branches being α-D-Manp-(1 →. G-EMP intervention reduced the loss of body weight, degree of colonic damage and shortening, disease activity index scores, and histopathology scores, while restoring goblet cell production and oxidative homeostasis, repairing colonic functions, and regulating inflammatory cytokines. RNA sequencing and Western blot analysis indicated that G-EMP exerts anti-inflammatory properties by suppressing the TLR4/MAPK/NF-κB inflammatory signaling pathway. G-EMP modulated the gut microbiota by improving its diversities, elevating the relative abundances of beneficial bacteria, declining the Firmicutes/Bacteroidota value, and regulating the level of short-chain fatty acids (SCFAs). Correlation analysis demonstrated strong links between SCFAs, gut microbiota, and the inflammatory response, indicating the potential of G-EMP to prevent colitis.

Optimization of medium compositions and X-ray irradiation to enhance monacolin K production by Monascus purpureus in submerged fermentation

The secondary metabolite Monacolin K (MK), derived from Monascus, exhibits potential lipid-lowering and anti-tumor effects. In this study, a mutant strain M. purpureus M400–6 was generated through X-ray treatment, resulting in an average MK production of 181.97 mg/L (a 54.20% increase compared to the parent strain M. purpureus M1) over five successive generations. Furthermore, optimization of medium compositions using response surface methodology led to a further enhancement in MK production by the mutant strain to 266.63 mg/L. Moreover, based on the outcomes of single-factor experiments, the addition of L-citrulline demonstrated a significantly higher level of enhancement in MK production. Therefore, a comparative transcriptome analysis was conducted to unveil the impact of L-citrulline on MK biosynthesis in M. purpureus. The data revealed a significant upregulation of glycolysis pathways, while oxidative phosphorylation including the TCA cycle and the electron transport chain, exhibited significant downregulation. Furthermore, the metabolisms of serine, glycine, threonine, alanine, aspartic acid and glutamate were found to be significantly disturbed. Additionally, the expressions of MPs and MK biosynthetic gene cluster showed a significant downregulation and upregulation respectively. Overall, these findings provide insights into enhancing MK production in submerged fermentation and elucidate the impact of L-citrulline on secondary metabolism.

Functional components and antioxidant activity were improved in ginger fermented by Bifidobacterium adolescentis and Monascus purpureus

Microbial fermentation, a widely used food processing technology, enhanced the biological activity and nutritional profile of raw materials. The impact of fermentation by Bifidobacterium adolescentis and Monascus purpureus on the functional components and antioxidant activity of ginger was investigated. The results showed that ginger fermented by the two strains notably increased the content of gingerol, total flavonoids, and total polyphenols, and enhanced its antioxidant capacity as measured by various assays such as DPPH, ABTS, and FRAP. The active components and antioxidant capacity were superior in ginger fermented by M. purpureus compared to B. adolescentis. The comparison of organic acid components demonstrated that the content of lactic acid and succinic acid was increased in ginger fermentation by B. adolescentis, while that of acetic acid, fumaric acid and citric acid was increased in ginger fermentation by M. purpureus. The Pearson correlation analysis showed a positive relation between the content of gingerol, total flavonoids, and total polyphenols, Monascus pigments, Monacolin K, and antioxidant capacity. Therefore, fermentation has the potential to enhance the functional components and antioxidant activity of ginger. This study might have implications for the development of ginger-based products and the theoretical basis for the deep processing of ginger.

Exploring the contribution of temperature-adapted microbiota to enzyme profile of saccharification in Daqu using metagenomics and metaproteomics

Temperature is a critical factor that influences the microbiota in Daqu, which provides essential enzymes for the saccharification process in Baijiu (Chinese liquor) production. However, the relationship between temperature-adapted microbiota and saccharification properties of Daqu remains unclear. In this study, a profile of 23 major saccharifying enzymes and 40 responsible genera was obtained from the metagenomic data of medium- and high-temperature Daqu (MT- and HT-Daqu). The high-temperature pattern (65 °C) primarily affected the saccharification potential of Daqu by promoting Bacillales (fold-change: 0.25–0.75), whereas inhibiting Lactobacillales (fold-change: 3.80–5.60) and Mucorales (fold-change: 5.65–7.09). Eurotiales only exhibited a slight increase (fold-change: 1.01–1.24) to low-temperature pattern (56 °C). Metaproteomic analysis further revealed a notable contribution of Eurotiales in facilitating saccharification. Amylolytic enzymes were primarily derived from Eurotiales species (Byssochlamys spectabilis, Monascus purpureus, Rasamsonia emersonii, and Thermomyces lanuginosus) and one Mucorales species, Lichtheimia romasa. Cellulolytic enzymes were produced by Thermoascus aurantiacus and Paecilomyces sp. Among them, L. romasa was the principal contributor under the low-temperature pattern. Whereas, in HT-Daqu, B. spectabilis, M. purpureus, and T. lanuginosus were the major contributors, as L. romasa is susceptible to higher temperatures. This study offers valuable guidance for targeted optimization of industrial production.

Enhancing extracellular monascus pigment production in submerged fermentation with engineered microbial consortia

In this study, we investigated the impact of microbial interactions on Monascus pigment (MP) production. We established diverse microbial consortia involving Monascus purpureus and Lactobacillus fermentum. The addition of Lactobacillus fermentum (4% at 48 h) to the submerged fermentation of M. purpureus resulted in a significantly higher MP production compared to that achieved using the single-fermentation system. Co-cultivation with immobilized L. fermentum led to a remarkable increase of 59.18% in extracellular MP production, while mixed fermentation with free L. fermentum caused a significant decrease of 66.93% in intracellular MPs, contrasting with a marginal increase of 4.52% observed during co-cultivation with immobilized L. fermentum and the control group respectively. The findings indicate an evident enhancement in cell membrane permeability of M. purpureus when co-cultivated with immobilized L. fementum. Moreover, integrated transcriptomic and metabolomic analyses were conducted to elucidate the regulatory mechanisms underlying MP biosynthesis and secretion following inoculation with immobilized L. fementum, with specific emphasis on glycolysis, steroid biosynthesis, fatty acid biosynthesis, and energy metabolism.

COMPASS core subunits MpSet1 and MpSwd3 regulate Monascus pigments synthesis in Monascus purpureus.

In eukaryotes, methylation of histone H3 at lysine 4 (H3K4me) catalyzed by the complex of proteins associated with Set1 (COMPASS) is crucial for the transcriptional regulation of genes and the development of organisms. In Monascus, the functions of COMPASS in establishing H3K4me remain unclear. This study first identified the conserved COMPASS core subunits MpSet1 and MpSwd3 in Monascus purpureus and confirmed their roles in establishing H3K4me2/3. Loss of MpSet1 and MpSwd3 resulted in slower growth and development and inhibited the formation of cleistothecia, ascospores, and conidia. The loss of these core subunits also decreased the production of extracellular and intracellular Monascus pigments (MPs) by 94.2%, 93.5%, 82.7%, and 82.5%, respectively. In addition, RNA high-throughput sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) showed that the loss of MpSet1 and MpSwd3 altered the expression of 2646 and 2659 genes, respectively, and repressed the transcription of MPs synthesis-related genes. In addition, the ΔMpset1 and ΔMpswd3 strains demonstrated increased sensitivity to cell wall stress with the downregulation of chitin synthase-coding genes. These results indicated that the COMPASS core subunits MpSet1 and MpSwd3 help establish H3K4me2/3 for growth and development, spore formation, and pigment synthesis in Monascus. These core subunits also assist in maintaining cell wall integrity.

Production and Characterization of Sorghum Sourdough Bread Sequentially Fermented with Monascus purpureus and Lactiplantibacillus plantarum

Production and Characterization of Sorghum Sourdough Bread Sequentially Fermented with Monascus purpureus and Lactiplantibacillus plantarum

Unveiling the potential of red koji polysaccharides: biosynthesis, extraction, and multifaceted biological activities.

Red koji polysaccharides, derived from the fermentation of Monascus, have been recognized for their health-enhancing properties. This article reviews their structural characteristics, biosynthesis pathways, and biological activities. It emphasizes the need for sustainable practices in fermentation and the optimization of extraction methods for scalable production. The significance of exploring the molecular mechanisms involved in their biosynthesis is also highlighted to enhance yield and efficiency. Research indicates that red koji polysaccharides possess diverse biological functions, beneficial for pharmaceutical applications due to their health benefits and minimal toxicity. The review points out the necessity for more detailed studies on key enzymes and genes in biosynthesis to improve production methods. It also identifies the current challenges in production scalability and extraction efficiency. Furthermore, while these polysaccharides show potential in pharmaceuticals, their clinical efficacy and mechanism of action in human subjects require further investigation. The review briefly explores potential structural modifications to improve their biological activities. The review concludes that red koji polysaccharides hold significant untapped potential, particularly in drug formulation. Future research should focus on overcoming current production and application challenges, including conducting clinical trials to validate their efficacy and exploring structural modifications for enhanced therapeutic benefits. This comprehensive understanding of red koji polysaccharides paves the way for their expanded application in the pharmaceutical industry. © 2024 Society of Chemical Industry.

Disruption of UDP-galactopyranose mutase expression: A novel strategy for regulation of galactomannan biosynthesis and monascus pigments secretion in Monascus purpureus M9

The impact of the cell wall structure of Monascus purpureus M9 on the secretion of extracellular monascus pigments (exMPs) was investigated. To modify the cell wall structure, UDP-galactopyranose mutase (GlfA) was knocked out using Agrobacterium-mediated transformation method, leading to a significant reduction in the Galf-based polysaccharide within the cell wall. Changes in mycelium morphology, sporogenesis, and the expression of relevant genes in M9 were also observed following the mutation. Regarding MPs secretion, a notable increase was observed in six types of exMPs (R1, R2, Y1, Y2, O1 and O2). Specifically, these exMPs exhibited enhancement of 1.33, 1.59, 0.8, 2.45, 2.89 and 4.03 times, respectively, compared to the wild-type strain. These findings suggest that the alteration of the cell wall structure could selectively influence the secretion of MPs in M9. The underlying mechanisms were also discussed. This research contributes new insights into the regulation of the synthesis and secretion of MPs in Monascus spp..