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.

Biosynthesis and Biotechnological Synthesis of Hydroxytyrosol.

Hydroxytyrosol (HT), a plant-derived phenolic compound, is recognized for its potent antioxidant capabilities alongside a spectrum of pharmacological benefits, including anti-inflammatory, anti-cancer, anti-bacterial, and anti-viral properties. These attributes have propelled HT into the spotlight as a premier nutraceutical and food additive, heralding a new era in health and wellness applications. Traditional methods for HT production, encompassing physico-chemical techniques and plant extraction, are increasingly being supplanted by biotechnological approaches. These modern methodologies offer several advantages, notably environmental sustainability, safety, and cost-effectiveness, which align with current demands for green and efficient production processes. This review delves into the biosynthetic pathways of HT, highlighting the enzymatic steps involved and the pivotal role of genetic and metabolic engineering in enhancing HT yield. It also surveys the latest progress in the biotechnological synthesis of HT, examining innovative strategies that leverage both genetically modified and non-modified organisms. Furthermore, this review explores the burgeoning potential of HT as a nutraceutical, underscoring its diverse applications and the implications for human health. Through a detailed examination of both the biosynthesis and biotechnological advances in HT production, this review contributes valuable insights to the field, charting a course towards the sustainable and scalable production of this multifaceted compound.

Therapeutic Potential of Fucoidan in Alleviating Histamine-Induced Liver Injury: Insights from Mice Studies.

Histamine, a bioactive component in certain foods such as Huangjiu has been associated with liver injury and disrupted intestinal balance. This study explored the potential therapeutic effects of fucoidan (FCD) in mitigating histamine-induced imbalances in mice. We found that FCD mitigated liver injury, reducing transaminases, oxidative stress, and inflammation. Histological improvements included decreased cell infiltration and necrosis. FCD restored tight junction proteins and suppressed inflammation-related genes. Western blot analysis revealed FCD's impact on TGF-ß1, p-AKT, AKT, CYP2E1, Grp78, NLRP3, Cas-1, and GSDMD. Gut LPS levels decreased with FCD. Gut microbiota analysis showed FCD's modulation effect, reducing Firmicutes and increasing Bacteroides. FCD demonstrates potential in alleviating histamine-induced liver injury, regulating inflammation, and influencing gut microbiota. Further research exploring higher dosages and additional parameters is warranted.

Melanin in Auricularia auricula: biosynthesis, production, physicochemical characterization, biological functions, and applications.

Auricularia auricular (A. auricula), a nutritious fungus and traditional medicinal resource, is known for melanin. This review aims to summarize the research progress on melanin in A. auricula, specifically focusing on biosynthesis, fermentation production, extraction processes, physicochemical characterization, biological functions, and applications. The biosynthesis of melanin in A. auricula primarily involves the oxidative polymerization reaction of phenolic compounds. To enhance melanin production, strategies such as deep fermentation culture, selection of optimal fermentation materials, and optimization of the culture medium have been employed. Various extraction processes have been compared to determine their impact on the physicochemical properties and stability of melanin. Moreover, the antioxidant and antibiofilm activities of A. auricula melanin, as well as its potential beneficial effects on the human body through in vivo experiments, have been investigated. These findings provide valuable insights into the application of A. auricula melanin and serve as a reference for future research in this field.

Encapsulation of caffeic acid phenethyl ester by self-assembled sorghum peptide nanoparticles: Fabrication, storage stability and interaction mechanisms.

Caffeic acid phenethyl ester (CAPE) is a naturally occurring phenolic compound with various biological activities. However, poor water solubility and storage stability limit its application. In this context, sorghum peptides were used to encapsulate CAPE. Sorghum peptides could self-assemble into regularly spherical nanoparticles (SPNs) by hydrophobic interaction and hydrogen bonds. Solubility of encapsulated CAPE was greatly increased, with 9.44 times higher than unencapsulated CAPE in water. Moreover, the storage stability of CAPE in aqueous solution was significantly improved by SPNs encapsulation. In vitro release study indicated that SPNs were able to delay CAPE release during the process of gastrointestinal digestion. Besides, fluorescence quenching analysis showed that a static quenching existed between SPNs and CAPE. The interaction between CAPE and SPNs occurred spontaneously, mainly driven by hydrophobic interactions. The above results suggested that SPNs encapsulation was an effective approach to improve the water solubility and storage stability of CAPE.

Fabrication of Magnetic Molecularly Imprinted Polymers for Selective Extraction of Dibutyl Phthalates in Food Matrices.

In this study, a novel magnetic molecularly imprinted polymeric material (Fe3O4@MOF@MIP-160) with a metal-organic backbone (Fe3O4@MOF) carrier was prepared using dibutyl phthalate (DBP) as a template. The material can be used for the efficient, rapid, and selective extraction of trace amounts of phthalic acid esters (PAEs) in food and can detect them via gas chromatography-mass spectrometry (GC-MS). The synthesis conditions of the materials were optimized to prepare the Fe3O4@MOF@MIP160 with the highest adsorption performance. Transmission electron microscopy (TEM), Fourier Transform Infrared Spectra (FT-IR), Vibration Sample Magnetic (VSM), and the Brunauer-Emmett-Teller (BET) method were used to characterize the materials. Compared with Fe3O4@MOF and the magnetic non-imprinted polymeric material (Fe3O4@MOF@NIP), Fe3O4@MOF@MIP-160 possesses the advantages of easy and rapid manipulation of magnetic materials, the advantages of high specific surface area and the stability of metal-organic frameworks, and the advantages of high selectivity of molecularly imprinted polymers. Fe3O4@MOF@MIP-160 has good recognition and adsorption capacity for di-butyl phthalate (DBP) and diethylhexyl phthalate (DEHP): the adsorption capacity for DBP and DEHP is 260 mg·g-1 and 240.2 mg·g-1, and the adsorption rate is fast (reaching equilibrium in about 20 min). Additionally, Fe3O4@MOF@MIP160 could be recycled six times, making it cost-effective, easy to operate, and time-saving as compared to traditional solid-phase extraction materials. The phthalate ester content in drinking water, fruit juice, and white wine was analyzed, with recoveries ranging from 70.3% to 100.7%. This proved that Fe3O4@MOF@MIP160 was suitable for detecting and removing PAEs from food matrices.

Preparation of Edible Colorant Lake Using Calcium Carbonate and ß-Carotene: Structural Characterization and Formation Mechanism Study.

This study prepared a novel ß-carotene colorant lake using calcium carbonate (CaCO3) and investigated the lake formation process and its basic characteristics. Kinetic adsorption analysis confirmed that medium pH (9.3) and medium temperature (40 °C) were more suitable for lake preparation, while desorption occurred, possibly due to crystalline transformation of CaCO3. The isothermal analysis and model fitting results suggested that the ß-carotene and CaCO3 particles combined via a monolayer adsorption process driven by physical force. Electrostatic attraction likely participated in the process due to the net negative surface charges of ß-carotene dispersion and positively charged groups on the CaCO3 particle surfaces. Ethanol, ultrasonic treatment, and drying method significantly influenced the immobilization efficiency (IE) of ß-carotene in the lake and light stability of the lake, without affecting its crystal form. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curves confirmed absorption of ß-carotene onto CaCO3. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated no obvious chemical bonds between ß-carotene and CaCO3. Energy-dispersive spectroscopy (EDS) confirmed the presence of ß-carotene on surfaces but not in the interior of the CaCO3 particles. The adsorption of ß-carotene by calcium carbonate was further confirmed to be a physical adsorption on surface.

Occurrence, Risk Implications, Prevention and Control of CIT in Monascus Cheese: A Review.

Monascus is a filamentous fungus that has been used in the food and pharmaceutical industries. When used as an auxiliary fermenting agent in the manufacturing of cheese, Monascus cheese is obtained. Citrinin (CIT) is a well-known hepatorenal toxin produced by Monascus that can harm the kidneys structurally and functionally and is frequently found in foods. However, CIT contamination in Monascus cheese is exacerbated by the metabolic ability of Monascus to product CIT, which is not lost during fermentation, and by the threat of contamination by Penicillium spp. that may be introduced during production and processing. Considering the safety of consumption and subsequent industrial development, the CIT contamination of Monascus cheese products needs to be addressed. This review aimed to examine its occurrence in Monascus cheese, risk implications, traditional control strategies, and new research advances in prevention and control to guide the application of biotechnology in the control of CIT contamination, providing more possibilities for the application of Monascus in the cheese industry.

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.

Dealuminated Beta zeolite reverses Ostwald ripening for durable copper nanoparticle catalysts.

Copper nanoparticle-based catalysts have been extensively applied in industry, but the nanoparticles tend to sinter into larger ones in the chemical atmospheres, which is detrimental to catalyst performance. In this work, we used dealuminated Beta zeolite to support copper nanoparticles (Cu/Beta-deAl) and showed that these particles become smaller in methanol vapor at 200°C, decreasing from ~5.6 to ~2.4 nanometers in diameter, which is opposite to the general sintering phenomenon. A reverse ripening process was discovered, whereby migratable copper sites activated by methanol were trapped by silanol nests and the copper species in the nests acted as new nucleation sites for the formation of small nanoparticles. This feature reversed the general sintering channel, resulting in robust catalysts for dimethyl oxalate hydrogenation performed with supported copper nanoparticles for use in industry.

Enhancing Monascus Pellet Formation for Improved Secondary Metabolite Production.

Filamentous fungi are well-known for their ability to form mycelial pellets during submerged cultures, a characteristic that has been extensively studied and applied. However, Monascus, a filamentous saprophytic fungus with a rich history of medicinal and culinary applications, has not been widely documented for pellet formation. This study aimed to investigate the factors influencing pellet formation in Monascus and their impact on citrinin production, a key secondary metabolite. Through systematic exploration, we identified pH and inoculum size as critical factors governing pellet formation. Monascus exhibited optimal pellet growth within the acidic pH range from 5 to 6, resulting in smaller, more homogeneous pellets with lower citrinin content. Additionally, we found that inoculum size played a vital role, with lower spore concentrations favoring the formation of small, uniformly distributed pellets. The choice of carbon and nitrogen sources also influenced pellet stability, with glucose, peptone, and fishmeal supporting stable pellet formation. Notably, citrinin content was closely linked to pellet diameter, with larger pellets exhibiting higher citrinin levels. Our findings shed light on optimizing Monascus pellet formation for enhanced citrinin production and provide valuable insights into the cultivation of this fungus for various industrial applications. Further research is warranted to elucidate the molecular mechanisms underlying these observations.

Characterization and Molecular Dynamics Simulation of a Lipase Capable of Improving the Functional Characteristics of an Egg-Yolk-Contaminated Liquid Egg White.

Lipase has great application potential in hydrolyzing residual yolk lipid in egg white liquid to restore its functional properties. In this study, a lipase gene from Bacillus subtilis was expressed in E. coli BL21 (DE3) and named Lip-IM. Results showed that although Lip-IM has stronger specificity for medium- and short-chain substrates than long-chain substrates (C16, C18), due to its excellent enzyme activity, it also has strong hydrolysis activity for long-chain substrates and maintained over 80% activity at 4-20 °C, but significantly reduced when the temperature exceeds 40 °C. The addition of 0.5% Lip-IM enhanced foaming ability by 26% (from 475 to 501%) and reduced liquid precipitation rate by 9% (from 57 to 48%). Furthermore, molecular dynamics (MD) simulations were run to investigate the conformational stability of Lip-IM at different temperatures. Results showed that Lip-IM maintained a stable conformation within the temperature range of 277-303 K. Fluctuations in the flexible area and backbone movement of proteins were identified as the main reasons for its poor thermal stability.

Study of a bioinspired rigid-flexible coupling structure based on dragonfly wing by optical/electron microscopy and finite element analysis.

In this work, mechanical properties of veins and membrane of dragonfly wing were studied by means of optical/electron microscopy, tensile test and nano-indentation. It indicates that veins exhibit significantly higher strength and elastic modulus, as compared with membrane. Furthermore, finite element analysis (FEA) demonstrates that the fluctuation of Von Mises stress and displacement between varying models is undermined, due to presence of the membrane, indicating higher stability. Consequently, according to FEA of varying models involving presence of membrane, the membrane in dragonfly wing not only provides the capability to fly, but also improves obviously the strength and stability of wing structure, despite of its significantly low strength and elastic modulus. It is found that based on proper biomimetic design, bioinspired rigid-flexible coupling structure exhibits superior strength and stability, as compared with conventional rigid structure, which will provide great potential to make novel, smart, and functional structures.

Effect of Exogenous and Endogenous Ectoine on Monascus Development, Metabolism, and Pigment Stability.

Monascus, a key player in fermented food production, is known for generating Monascus pigments (MPs) and monacolin K (MK), possessing bioactive properties. However, the limited stability of MPs and mycotoxin citrinin (CTN) constrain the Monascus industry. Extremolytes like ectoine, derived from bacteria, exhibit cytoprotective potential. Here, we investigated the impact of ectoine on Monascus purpureus ATCC 16365, emphasizing development and secondary metabolism. Exogenous 5 mM ectoine supplementation substantially increased the yields of MPs and MK (105%-150%) and reduced CTN production. Ectoine influenced mycelial growth, spore development, and gene expression in Monascus. Remarkably, ectoine biosynthesis was achieved in Monascus, showing comparable effects to exogenous addition. Notably, endogenous ectoine effectively enhanced the stability of MPs under diverse stress conditions. Our findings propose an innovative strategy for augmenting the production and stability of bioactive compounds while reducing CTN levels, advancing the Monascus industry.

The regulatory functions of oxylipins in fungi: A review.

Quorum sensing (QS) is a communication mechanism between microorganisms originally found in bacteria. In recent years, an important QS mechanism has been discovered in the field of fungi, namely, the lipoxygenase compound oxylipin of arachidonic acid acts as a QS molecule in life cycle control, particularly in the sexual and asexual development of fungi. However, the role of oxylipins in mediating eukaryotic communication has not been previously described. In this paper, we review the regulatory role of oxylipins and the underlying mechanisms and discuss the potential for application in major fungi. The role of oxylipin as a fungal quorum-sensing molecule is the main focus of the review. Besides, the quorum regulation of fungal morphological transformation, biofilm formation, virulence factors, secondary metabolism, infection, symbiosis, and other physiological behaviors are discussed. Moreover, future prospectives and applications are elaborated as well.

Histone Acetyltransferase Rtt109 Regulates Development, Morphogenesis, and Citrinin Biosynthesis in Monascus purpureus.

Histone acetyltransferase (HAT) has been reported to be pivotal for various physiological processes in many fungi. However, the functions that HAT Rtt109 perform in edible fungi Monascus and the underlying mechanism remains unclear. Here, we identified the rtt109 gene in Monascus, constructed the rtt109 knockout strain (Δrtt109) and its complementary strain (Δrtt109:com) by CRISPR/Cas9 methods, and functionally characterized the roles that Rtt109 play in Monascus. Deletion of rtt109 significantly reduced conidia formation and colony growth, whereas, it increased the yield of Monascus pigments (MPs) and citrinin (CTN). Further real-time quantitative PCR (RT-qPCR) analysis indicated that Rtt109 remarkably affected the transcriptional expression of key genes related to development, morphogenesis, and secondary metabolism of Monascus. Together, our results revealed the critical roles of HAT Rtt109 in Monascus, and enriched our current knowledge of the development and regulation of secondary metabolism in fungi, throwing light on restraining or eliminating citrinin in the development and industrial applications of Monascus.

Syringic Acid Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice by Modulating Gut Microbiota.

Inflammatory bowel disease is known to be associated with alterations in gut microbiota. The bioactive compound syringic acid has been shown to alleviate inflammatory bowel disease, but its interaction with gut microbiota and mechanism of action remain unclear. To address this, we conducted a study in which we investigated the potential benefits of syringic acid in a mouse model of dextran sulfate sodium-induced colitis through gut microbiota modulation. Our results show that oral administration of syringic acid effectively reduced symptoms of colitis, as indicated by reduced disease activity index, and histopathology scores. Moreover, syringic acid administration enriched the abundance of Alistipes and norank_f__norank_o__Gastranaerophilales in mice, suggesting a restoration of impaired gut microbiota. Notably, we found that the effects of syringic acid were similar to those of fecal microbiota transplantation in dextran sulfate sodium-induced mice. Further analysis revealed that syringic acid inhibited the NLRP3-Cas-1-GSDMD-IL-1ß inflammatory vesicle signaling pathway, leading to amelioration of colonic inflammation in a gut microbiota-dependent manner. Our findings demonstrate the potential of syringic acid as a preventive and therapeutic agent for inflammatory bowel disease.

Rhodium nanoparticles supported on silanol-rich zeolites beyond the homogeneous Wilkinson's catalyst for hydroformylation of olefins.

Hydroformylation is one of the largest industrially homogeneous processes that strongly relies on catalysts with phosphine ligands such as the Wilkinson's catalyst (triphenylphosphine coordinated Rh). Heterogeneous catalysts for olefin hydroformylation are highly desired but suffer from poor activity compared with homogeneous catalysts. Herein, we demonstrate that rhodium nanoparticles supported on siliceous MFI zeolite with abundant silanol nests are very active for hydroformylation, giving a turnover frequency as high as ~50,000 h-1 that even outperforms the classical Wilkinson's catalyst. Mechanism study reveals that the siliceous zeolite with silanol nests could efficiently enrich olefin molecules to adjacent rhodium nanoparticles, enhancing the hydroformylation reaction.

A Novel Microbial Consortia Catalysis Strategy for the Production of Hydroxytyrosol from Tyrosine.

Hydroxytyrosol, a valuable plant-derived phenolic compound, is increasingly produced from microbial fermentation. However, the promiscuity of the key enzyme HpaBC, the two-component flavin-dependent monooxygenase from Escherichia coli, often leads to low yields. To address this limitation, we developed a novel strategy utilizing microbial consortia catalysis for hydroxytyrosol production. We designed a biosynthetic pathway using tyrosine as the substrate and selected enzymes and overexpressing glutamate dehydrogenase GdhA to realize the cofactor cycling by coupling reactions catalyzed by the transaminase and the reductase. Additionally, the biosynthetic pathway was divided into two parts and performed by separate E. coli strains. Furthermore, we optimized the inoculation time, strain ratio, and pH to maximize the hydroxytyrosol yield. Glycerol and ascorbic acid were added to the co-culture, resulting in a 92% increase in hydroxytyrosol yield. Using this approach, the production of 9.2 mM hydroxytyrosol was achieved from 10 mM tyrosine. This study presents a practical approach for the microbial production of hydroxytyrosol that can be promoted to produce other value-added compounds.