The serine/threonine protein kinase MpSTE1 directly governs hyphal branching in Monascus spp.

Monascus spp. are commercially important fungi due to their ability to produce beneficial secondary metabolites such as the cholesterol-lowering agent lovastatin and natural food colorants azaphilone pigments. Although hyphal branching intensively influenced the production of these secondary metabolites, the pivotal regulators of hyphal development in Monascus spp. remain unclear. To identify these important regulators, we developed an artificial intelligence (AI)-assisted image analysis tool for quantification of hyphae-branching and constructed a random T-DNA insertion library. High-throughput screening revealed that a STE kinase, MpSTE1, was considered as a key regulator of hyphal branching based on the hyphal phenotype. To further validate the role of MpSTE1, we generated an mpSTE1 gene knockout mutant, a complemented mutant, and an overexpression mutant (OE::mpSTE1). Microscopic observations revealed that overexpression of mpSTE1 led to a 63% increase in branch number while deletion of mpSTE1 reduced the hyphal branching by 68% compared to the wild-type strain. In flask cultures, the strain OE::mpSTE1 showed accelerated growth and glucose consumption. More importantly, the strain OE::mpSTE1 produced 9.2 mg/L lovastatin and 17.0 mg/L azaphilone pigments, respectively, 47.0% and 30.1% higher than those of the wild-type strain. Phosphoproteomic analysis revealed that MpSTE1 directly phosphorylated 7 downstream signal proteins involved in cell division, cytoskeletal organization, and signal transduction. To our best knowledge, MpSTE1 is reported as the first characterized regulator for tightly regulating the hyphal branching in Monascus spp. These findings significantly expanded current understanding of the signaling pathway governing the hyphal branching and development in Monascus spp. Furthermore, MpSTE1 and its analogs were demonstrated as promising targets for improving production of valuable secondary metabolites. KEY POINTS: • MpSTE1 is the first characterized regulator for tightly regulating hyphal branching • Overexpression of mpSTE1 significantly improves secondary metabolite production • A high-throughput image analysis tool was developed for counting hyphal branching.

CRISPR/Cas9 system is a suitable gene targeting editing tool to filamentous fungus Monascus pilosus.

Monascus pilosus has been used to produce lipid-lowering drugs rich in monacolin K (MK) for a long period. Genome mining reveals there are still many potential genes worth to be explored in this fungus. Thereby, efficient genetic manipulation tools will greatly accelerate this progress. In this study, we firstly developed the protocol to prepare protoplasts for recipient of CRISPR/Cas9 system. Subsequently, the vector and donor DNA were co-transformed into recipients (106 protoplasts/mL) to produce 60-80 transformants for one test. Three genes (mpclr4, mpdot1, and mplig4) related to DNA damage response (DDR) were selected to compare the gene replacement frequencies (GRFs) of Agrobacterium tumefaciens-mediated transformation (ATMT) and CRISPR/Cas9 gene editing system (CGES) in M. pilosus MS-1. The results revealed that GRF of CGES was approximately five times greater than that of ATMT, suggesting that CGES was superior to ATMT as a targeting gene editing tool in M. pilosus MS-1. The inactivation of mpclr4 promoted DDR via the non-homologous end-joining (NHEJ) and increased the tolerances to DNA damaging agents. The inactivation of mpdot1 blocked DDR and led to the reduced tolerances to DNA damaging agents. The inactivation of mplig4 mainly blocked the NHEJ pathway and led to obviously reduced tolerances to DNA damaging agents. The submerged fermentation showed that the ability to produce MK in strain Δmpclr4 was improved by 52.6% compared to the wild type. This study provides an idea for more effective exploration of gene functions in Monascus strains. KEY POINTS: • A protocol of high-quality protoplasts for CGES has been developed in M. pilosus. • The GRF of CGES was about five times that of ATMT in M. pilosus. • The yield of MK for Δmpclr4 was enhanced by 52.6% compared with the wild type.

Screening Antibacterial Photodynamic Effect of Monascus Red Yeast Rice (Hong-Qu) and Mycelium Extracts.

The fungus Monascus is a well-known source of secondary metabolites with interesting pharmaceutical and nutraceutical applications. In particular, Monascus pigments possess a wide range of biological activities (e.g. antimicrobial, antioxidant, anti-inflammatory or antitumoral). To broaden the scope of their possible application, this study focused on testing Monascus pigment extracts as potential photosensitizing agents efficient in antimicrobial photodynamic therapy (aPDT) against bacteria. For this purpose, eight different extracts of secondary metabolites from the liquid- and solid-state fermentation of Monascus purpureus DBM 4360 and Monascus sp. DBM 4361 were tested against Gram-positive and Gram-negative model bacteria, Bacillus subtilis and Escherichia coli and further screened for ESKAPE pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. To the bacterial culture, increasing concentration of extracts was added and it was found that all extracts showed varying antimicrobial activity against Gram-positive bacteria in dark, which was further increased after irradiation. Gram-negative bacteria were tolerant to the extracts' exposure in the dark but sensitivity to almost all extracts that occurred after irradiation. The Monascus sp. DBM 4361 extracts seemed to be the best potential candidate for aPDT against Gram-positive bacteria, being efficient at low doses, i.e. the lowest total concentration of Monascus pigments exhibiting aPDT effect was 3.92 ± 1.36 mg/L for E. coli. Our results indicate that Monascus spp., forming monascuspiloin as the major yellow pigment and not-forming mycotoxin citrinin, is a promising source of antimicrobials and photoantimicrobials.

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.

Structural elucidation and complete NMR spectral assignments of Monascus monacolin analogues.

Three new monacolin analogues, 3,6-dihydroxy-monacolin P (1), 6-methoxy monacolin S (2), and 6-methoxy dehydromonacolin S (3), were isolated from a fraction that strongly inhibited 3-hydroxy-3-methylglutaryl-CoA reductase from the ethyl acetate portion of red yeast rice ethanol extract. Their structures were determined through a combination of 1D and 2D NMR experiments, mass spectrometry analysis, and known literature reports.

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.

Bidirectional fermentation of Monascus and Mulberry leaves enhances GABA and pigment contents: establishment of strategy, studies of bioactivity and mechanistic.

Bidirectional fermentation is a technology that utilizes fungi to ferment medicinal edible substrates, with synergistic and complementary advantages. In this work, a fermentation strategy was established to produce a high yield of γ-aminobutyric acid (GABA) and Monascus pigments (MPs) using Monascus and mulberry leaves (MLs). Firstly, the basic fermentation parameters were determined using single-factor experiments, followed by Plackett-Burman (PB) experimental design to identify MLs, glucose, peptone, and temperature as significant influencing factors. The fermentation parameters were optimized using an artificial neural network (ANN). Finally, the effects of bidirectional fermentation of MLs and Monascus were investigated by bioactivity analysis, microstructure observation, and RT-qPCR. The outcomes showed that the bidirectional fermentation significantly increased the bioactive content and promoted the secondary metabolism of Monascus. The established fermentation conditions were 44.2 g/L of MLs, 57 g/L of glucose, 15 g/L of peptone, 1 g/L of MgSO4, 2 g/L of KH2PO4, 8% (v/v) of inoculum, 180 rpm, initial pH 6, 32 °C and 8 days. The content of GABA reached 13.95 g/L and the color value of MPs reached 408.07 U/mL. This study demonstrated the feasibility of bidirectional fermentation of MLs and Monascus, providing a new idea for the application of MLs and Monascus.

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.

Combined volatile compounds and non-targeted metabolomics analysis reveals variation in flavour characteristics, metabolic profiles and bioactivity of mulberry leaves after Monascus purpureus fermentation.

BACKGROUND: Mulberry leaves (MLs) are widely used in food because of their nutritional and functional characteristics. However, plant cell walls and natural bitterness influence nutrient release and the flavor properties of MLs. Liquid-state fermentation using Monascus purpureus (LFMP) is a common processing method used to improve food properties. The present study used headspace solid-phase micro extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and non-targeted metabolomics to examine changes in volatile and non-volatile metabolites in MLs. The transformation mechanism of LFMP was investigated by microscopic observation and dynamic analysis of enzyme activity, and changes in the biological activity of MLs were analyzed. RESULTS: LFMP significantly increased total phenolics, total flavonoids, free amino acids and soluble sugars in MLs, at the same time as decreasing phytic acid levels. In total, 92 volatile organic compounds (VOCs) were identified and quantified. VOCs such as (2R,3R)-(-)-2,3-butanediol, terpineol and eugenol showed some improvement in the flavour characteristics of MLs. By using non-targeted metabolomics, 124 unique metabolites in total were examined. LFMP altered the metabolic profile of MLs, mainly in plant secondary metabolism, lipid metabolism and amino acid metabolism. Microscopic observation and dynamic analysis of enzyme activity indicated that LFMP promoted cell wall degradation and biotransformation of MLs. In addition, LFMP significantly increased the angiotensin I-converting enzyme and α-glucosidase inhibitory activity of MLs. CONCLUSION: LFMP altered the flavour characteristics, metabolite profile and biological activity of MLs. These findings will provide ideas for the processing of MLs into functional foods. In addition, they also provide useful information for biochemical studies of fermented MLs. © 2023 Society of Chemical Industry.

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.

The response pattern of the microbial community structure and metabolic profile of jiupei to Bacillus subtilis JP1 addition during baijiu fermentation.

BACKGROUND: Baijiu brewing is a complex and multifaceted multimicrobial co-fermentation process, in which various microorganisms interact to form an interdependent micro-ecosystem, subsequently influencing metabolic activities and compound production. Among these microorganisms, Bacillus, an important bacterial genus in the liquor brewing process, remains unclear in its role in shaping the brewing microbial community and its functional metabolism. RESULTS: A baijiu fermentation system was constructed using B. subtilis JP1 isolated from native jiupei (grain mixture) combined with daqu (a saccharifying agent) and huangshui (a fermentation byproduct). Based on high-throughput amplicon sequencing analysis, it was evident that B. subtilis JP1 significantly influences bacterial microbial diversity and fungal community structure in baijiu fermentation. Of these, Aspergillus and Monascus emerge as the most markedly altered microbial genera in the jiupei community. Based on co-occurrence networks and bidirectional orthogonal partial least squares discriminant analysis models, it was demonstrated that the addition of B. subtilis JP1 intensified microbial interactions in jiupei fermentation, consequently enhancing the production of volatile flavor compounds such as heptanoic acid, butyl hexanoate and 3-methylthiopropanol in jiupei. CONCLUSION: B. subtilis JP1 significantly alters the microbial community structure of jiupei, enhancing aroma formation during fermentation. These findings will contribute to a broader application in solid-state fermentation. © 2024 Society of Chemical Industry.

Linoleic acid functions as a quorum-sensing molecule in Monascus purpureus-Saccharomyces cerevisiae co-culture.

When Monascus purpureus was co-cultured with Saccharomyces cerevisiae, we noted significant changes in the secondary metabolism and morphological development of Monascus. In yeast co-culture, although the pH was not different from that of a control, the Monascus mycelial biomass increased during fermentation, and the Monacolin K yield was significantly enhanced (up to 58.87% higher). However, pigment production did not increase. Co-culture with S. cerevisiae significantly increased the expression levels of genes related to Monacolin K production (mokA-mokI), especially mokE, mokF, and mokG. Linoleic acid, that has been implicated in playing a regulating role in the secondary metabolism and morphology of Monascus, was hypothesized to be the effector. Linoleic acid was detected in the co-culture, and its levels changed during fermentation. Addition of linoleic acid increased Monacolin K production and caused similar morphological changes in Monascus spores and mycelia. Exogenous linoleic acid also significantly upregulated the transcription levels of all nine genes involved in the biosynthesis of Monacolin K (up to 69.50% higher), consistent with the enhanced Monacolin K yield. Taken together, our results showed the effect of S. cerevisiae co-culture on M. purpureus and suggested linoleic acid as a specific quorum-sensing molecule in Saccharomyces-Monascus co-culture.

Regulation of the pigment production by changing Cell morphology and gene expression of Monascus ruber in high-sugar synergistic high-salt stress fermentation.

AIMS: Extreme environment of microbial fermentation is the focus of research, which provides new thinking for the production and application of Monascus pigments (MPs). In this work, the high-sugar synergistic high-salt stress fermentation (HSSF) of MPs was investigated. METHODS AND RESULTS: The Monascus fungus grew well under HSSF conditions with 35 g L-1 NaCl and 150 g L-1 glucose, and the extracellular yellow pigment and intracellular orange pigment yield in HSSF was 98% and 43% higher than that in conventional fermentation, respectively. Moreover, the mycelial morphology was maintained in a better status with more branches and complete surface structure, indicating good biocatalytic activity for pigment synthesis. Four extracellular yellow pigments (Y1, Y2, Y3, and Y4) were transformed into each other, and ratio of the relative content of intracellular orange pigments to yellow pigments (O/Y) significantly (P < 0.05) changed. Moreover, the ratio of unsaturated fatty acids to saturated fatty acids (unsaturated/saturated) was significantly (P < 0.05) increased, indicating that the metabolism and secretion of intracellular and extracellular pigment might be regulated in HSSF. The pigment biosynthesis genes mppB, mppC, mppD, MpPKS5, and MpFasB2 were up-regulated, whereas the genes mppR1, mppR2, and mppE were down-regulated, suggesting that the gene expression to regulate pigment biosynthesis might be a dynamic change process in HSSF. CONCLUSIONS: The HSSF system of MPs is successfully performed to improve the pigment yields. Mycelial morphology is varied to enhanced pigment secretion, and gene expression is dynamically regulated to promote pigment accumulation in HSSF.

Mrhst4 gene, coding for NAD+-dependent deacetylase is involved in citrinin production of Monascus ruber.

AIMS: In this study, Mrhst4, encoding a member of NAD+-dependent histone deacetylase (HDAC), was deleted to evaluate its regulation on the production of Monascus azaphilone pigments (MonAzPs) and mycotoxin, as well as the developmental process in Monascusruber. METHODS AND RESULTS: Agrobacterium tumefaciens-mediated transformation was applied in this study to generate the Mrhst4 null strain. Mrhst4-deleted strain did not display obvious differences in the sexual and asexual reproduction, colonial morphology, and micro-morphology. UV-Vis scan and UPLC detection showed that disruption of Mrhst4 significantly increased the MonAzPs yields, and citrinin content was dramatically enhanced during the tested period. RT-qPCR results showed that the absence of Mrhst4 significantly increased the relative expression of citrinin biosynthetic pathway genes including pksCT, mrl1, mrl2, mrl4, mrl6, and mrl7. The Western blot assay suggested that deletion of Mrhst4 could significantly elevate the acetylation levels of H3K4, H3K9, H3K18, H3K56, and H4K12, but attenuated the lysine acetylation modification of H4Pan, H4K8, and H4K16. CONCLUSION: MrHst4 is an important regulator involved in secondary metabolism in Monascus ruber. In particular, MrHst4 plays a pivotal role in regulation of citrinin production.

Genetic responses to adding nitrates to improve hydrophilic yellow pigment in Monascus fermentation.

Nitrates can stimulate the biosynthesis of hydrophilic yellow pigments (HYPs) in Monascus ruber CGMCC 10910. To explore the molecular mechanisms whereby nitrates (NaNO3 and NH4NO3) regulate HYP production, an integrated transcriptomic and proteomic analysis was conducted in this study. Nitrate addition led to an approximately 75% higher HYP production compared with the untreated group, especially compounds Y3 and Y4. Comparative transcriptomic analysis found that mpigsA, H, K, L, and P genes involved in yellow pigment biosynthesis were significantly upregulated. In addition, pigment biosynthesis-related (carbon catabolism, amino acid metabolism, polyketide synthesis, and fatty acid metabolism) genes were upregulated to provide precursors and energy for HYP biosynthesis and cell growth. Secretion-related (cytomembrane ergosterol biosynthetic, and transport) pathways were also noticeably regulated to accelerate transmembrane transport of HYPs. Meanwhile, proteomic analysis showed that nitrates improved the protein expression of hybrid polyketide synthase-nonribosomal peptide synthetase, oxidoreductase, glucoamylase, endo-1,4-beta-xylanase, O-acetylhomoserine, and isocitrate lyase to enhance HYP production. These findings demonstrated the regulatory mechanism of nitrates for enhancing HYP production in Monascus. KEY POINTS: • Nitrates stimulated the biosynthesis of Monascus hydrophilic yellow pigments (HYPs) • Nitrates affected transcriptional level of pigment biosynthesis- and transport genes • Increased expression of hybrid PKS-NRPS and transporters promoted production of HYPs.

Regulation mechanism of lipids for extracellular yellow pigments production by Monascus purpureus BWY-5.

The biosynthesis and secretion of Monascus pigments are closely related to the integrity of the cell membrane, which determines the composition of lipids and its content in cell membrane. The present study aimed to thoroughly describe the changes of lipid profiling in Monascus purpureus BWY-5, which was screened by carbon ion beam irradiation (12C6+) to almost single yield extracellular Monascus yellow pigments (extra-MYPs), by absolute quantitative lipidomics and tandem mass tags (TMT) based quantitative proteomic. 12C6+ irradiation caused non-lipid oxidation damage to Monascus cell membrane, leading to an imbalance in cell membrane lipid homeostasis. This imbalance was attributed to significant changes not only in the composition but also in the content of lipids in Monascus, especially the inhibition of glycerophospholipid biosynthesis. Integrity of plasma membrane was maintained by the increased production of ergosterol, monogalactosylmonoacylglycerol (MGMG) and sulfoquinovosylmonoacylglycerol (SQMG), while mitochondrial membrane homeostasis was maintained by the increase of cardiolipin production. The growth and extra-MYPs production of Monascus BWY-5 have been regulated by the promotion of sphingolipids (ceramide and sulfatide) biosynthesis. Simultaneous, energy homeostasis may be achieved by increase of TG synthesis and Ca2+/Mg2+-ATPase activity. These finding suggest ergosterol, cardiolipin, sphingolipids, MGMG and SQMG play a key facilitating role in cytomembrane lipid homeostasis maintaining for Monascus purpureus BWY-5, and then it is closely related to cell growth and extra-MYPs production. KEY POINTS: 1. Energy homeostasis in Monascus purpureus BWY-5 was achieved by increase of TG synthesis and Ca2+/Mg2+-ATPase activity. 2. Integrity of plasma membrane in Monascus purpureus BWY-5 was maintained by the increased production of ergosterol. 3. Mitochondrial membrane homeostasis in Monascus purpureus BWY-5 was maintaed by the increase of cardiolipin synthesis.

Optimization of the hongqu starter preparation process for the manufacturing of red mold rice with high gamma-aminobutyric acid production by solid-state fermentation.

Red mold rice (RMR) generally contains gamma-aminobutyric acid (GABA), which has several physiological functions. Monascus purpureus M162, with a high GABA production of 15.10 mg/g was generated by atmospheric and room temperature plasma mutation. Furthermore, we conducted a response surface methodology to produce a premium hongqu starter. The results revealed that under optimal conditions, that is, a substrate containing brown rice and bran in a brown rice: bran ratio of 9:1 (wt/wt), an inoculation size of 21.50 mL/100 g, a mixing frequency of one time/9 h, and a cultivation time of 7.20 days, the number of active spores, α-amylase activity, and saccharification power activity was 4.15 × 107 spores/g, 155 U/g, and 3260 U/g in the high-quality starter, respectively. These values were 224.32-fold, 139.64%, and 141.74% higher than those obtained with M. purpureus M162 inoculated into steamed indica rice, respectively, and 153.70-fold, 267.24%, and 151.63% higher than those obtained with the parent strain M. purpureus M1, respectively. The premium hongqu starter of M. purpureus M162 was inoculated into steamed indica rice to produce RMR with 15.93 mg/g of GABA. In conclusion, we proposed a novel strategy for functional RMR production with high GABA concentrations by solid-state fermentation with Monascus spp.

Monascin and ankaflavin-Biosynthesis from Monascus purpureus, production methods, pharmacological properties: A review.

Monascus purpureus copiously yields beneficial secondary metabolites , including Monascus pigments, which are broadly used as food additives, as a nitrite substitute in meat products, and as a colorant in the food industry. Monascus yellow pigments (monascin and ankaflavin) have shown potential antidiabetic, antibacterial, anti-inflammatory, antidepressant, antibiotic, anticancer, and antiobesity activities. Cosmetic and textile industries are other areas where it has established its potential as a dye. This paper reviews the production methods of Monascus yellow pigments, biosynthesis of Monascus pigments from M. purpureus, factors affecting yellow pigment production during fermentation, and the pharmacological properties of monascin and ankaflavin.

Secondary Metabolites with Antifungal Activities from Mangrove Derived Fungus Monascus purpureus WMD2424.

The mold Monascus, also called red yeast rice, anka, or koji, has been used as the natural food coloring agent and food additives for more than 1000 years in Asian countries. It has also been used in Chinese herbology and traditional Chinese medicine due to its easing digestion and antiseptic effects. However, under different culture conditions, the ingredients in Monascus-fermented products may be changed. Therefore, an in-depth understanding of the ingredients, as well as the bioactivities of Monascus-derived natural products, is important. Here, through the thorough investigation into the chemical constituents of M. purpureus wmd2424, five previously undescribed compounds, monascuspurins A-E (1-5), were isolated from the EtOAc extract of mangrove-derived fungus Monascus purpureus wmd2424 cultured in RGY medium. All the constituents were confirmed via HRESIMS and 1D- and 2D-NMR spectroscopy. Their antifungal activity was also evaluated. Our results showed that four constituents (compounds 3-5) possessed mild antifungal activity against Aspergillus niger, Penicillium italicum, Candida albicans, and Saccharomyces cerevisiae. It is worth mentioning that the chemical composition of the type strain Monascus purpureus wmd2424 has never been studied.

Performance and mechanism of co-culture of Monascus purpureus, Lacticaseibacillus casei, and Saccharomyces cerevisiae to enhance lovastatin production and lipid-lowering effects.

To facilitate lipid-lowering effects, a lovastatin-producing microbial co-culture system (LPMCS) was constituted with a novel strain Monascus purpureus R5 in combination with Lacticaseibacillus casei S5 and Saccharomyces cerevisiae J7, which increased lovastatin production by 54.21% compared with the single strain R5. Response Surface Methodology (RSM) optimization indicated lovastatin yield peaked at 7.43 mg/g with a fermentation time of 13.88 d, water content of 50.5%, and inoculum ratio of 10.27%. Meanwhile, lovastatin in LPMCS co-fermentation extracts (LFE) was qualitatively and quantitatively analyzed by Thin-Layer Chromatography (TLC) and High-Performance Liquid Chromatography (HPLC). Cellular experiments demonstrated that LFE exhibited no obvious cytotoxicity to L-02 cells and exhibited excellent biosafety. Most notably, high-dose LFE (100 mg/L) exhibited the highest reduction of lipid accumulation, total cholesterol, and triglycerides simultaneously in oleic acid-induced L-02 cells, which decreased by 71.59%, 38.64%, and 58.85% than untreated cells, respectively. Overall, LPMCS provides a potential approach to upgrade the lipid-lowering activity of Monascus-fermented products with higher health-beneficial effects.